Buddhist philosophy facts for kids

Buddhism
Basic terms
Three Jewels Four Noble Truths Dukkha Samudaya Nirodha Marga Noble Eightfold Path Buddhahood Enlightenment Nirvana
People
Gautama Buddha Dalai Lama Bodhisattva Sangha
Schools
Theravada Mahayana Zen Vajrayana Nyingma Kagyu Sakya Gelug
Practices
study Dharma Meditation Metta

Buddhist philosophy is a way of thinking that grew from the Buddhist religion in Ancient India. It includes all the deep questions and logical ways of thinking that different schools of Buddhism developed. This started after Gautama Buddha passed away (around 5th century BCE). It continued as Buddhism spread across Asia.

Buddhist thinking mixes deep thought with meditation practice. The Buddhist religion offers many ways to find freedom. As Buddhism grew from India to Sri Lanka, East Asia, and Southeast Asia, Buddhist thinkers explored many topics. These include how the universe works (cosmology), how we should live (ethics), how we know things (epistemology), and the nature of reality. They also thought about the mind, time, and how to reach spiritual freedom (soteriology).

Early Buddhism was based on what people could learn through their senses and mind. The Buddha often avoided answering some big questions about the universe. He felt these questions did not help people find freedom. Instead, they just led to more thinking. However, he did teach ideas like dependent arising, karma, and rebirth. These ideas have deep meanings about reality.

Different Buddhist schools often debated specific points of Buddhist philosophy. They also argued with Hindu and Jaina thinkers. These discussions led to many different schools like Abhidharma and Mahāyāna traditions. Some of these include Prajñāpāramitā, Mādhyamaka, and Yogācāra. A common goal in Buddhist philosophy is to find a Middle Way between extreme ideas.

Buddhist Philosophy Through Time

The way Buddhist philosophy developed in India can be split into three main parts:

• The first part includes the very early Buddhist teachings. These came from the oral traditions during the life of Gautama Buddha. All later Buddhist schools share these ideas.
• The second part is about "scholarly" Buddhism, not Mahayana. This is seen in the Abhidharma texts from around the 3rd century BCE. These texts organized and classified the ideas from the early Buddhist texts. The Theravada Abhidhamma school's philosophy is part of this time.
• The third part is about Mahāyāna Buddhism, starting around the 1st century CE. This movement focuses on the path of a bodhisattva. A bodhisattva is someone who delays their own freedom to help others. This phase includes schools like Prajñāpāramitā, Mādhyamaka, and Yogācāra.

Ideas from all three of these phases are used and developed further in the many Buddhist groups that exist today.

Why Study Buddhist Philosophy?

In ancient India, philosophy was mostly about finding spiritual freedom. It aimed to help people reach a state of peace. Peter Deller Santina, who studied Buddhist philosophy, explains:

"Philosophical systems in India were rarely just about ideas. Almost all great Indian philosophies, like Sāṃkhya and Mādhyamaka, focused on showing a way to freedom. It was understood that if you truly understood these philosophies, you could reach a state free from suffering. If we forget this, we miss the real meaning of Indian and Buddhist philosophy."

For Indian Buddhist thinkers, the teachings of Gautama Buddha were not just to be believed. They were to be checked through logical thinking and investigation. Early Buddhist texts say that a person follows the Buddha's teachings after thinking about them wisely. Disciples are also told to "investigate" and "check" the teachings. The Buddha even expected his students to question him, as shown in the Vīmaṃsaka Sutta.

The Buddha and Early Teachings

The Buddha's Wisdom

Scholars debate if Gautama Buddha himself was a philosopher. Siddartha Gautama (around 5th century BCE) was a wandering holy man from northern India. His teachings are found in texts like the Pāli Nikayas. It is hard to know exactly when these texts were written. There is also disagreement on how much of this material came from the Buddha himself. The Buddha's main goal was to help people reach nirvāṇa, a state of perfect peace. But his teachings also explain the cause of human suffering, what a person's identity is, and how to gain wisdom.

The Middle Way

The Buddha called his teaching "the Middle Way". In the Dharmacakrapravartana Sūtra, this means his teachings avoid extremes. It is a path between harsh asceticism (denying the body) and seeking too much pleasure. Many holy people in the Buddha's time focused on denying the body through practices like fasting. They believed this would free the mind. But Gautama Buddha realized that the mind depends on the body. A weak body would not allow the mind to be trained. So, Buddhism is not about being rich or poor. It is about how people react to life's situations.

Another idea from the Buddha is "teaching through the middle." This is a middle path between believing things last forever (eternalism) and believing they completely disappear (annihilationism). It also avoids the extremes of existence and non-existence. This idea became very important in later Buddhist thought. All Buddhist philosophies claim to follow a middle path.

Core Teachings

Besides the Middle Way, some basic teachings appear often in early Buddhist texts. Scholars believe the Buddha taught these key ideas:

• The Four Noble Truths: These explain the cause of suffering (duḥkha).
• The Noble Eightfold Path: This shows the way to spiritual freedom (mokṣa).
• The four dhyānas: These are types of deep meditation.
• The three marks of existence: These are three qualities of all things: suffering (duḥkha), impermanence (anicca), and non-self (anattā).
• The five aggregates of clinging (skandhā): These explain what makes up a person and physical existence.
• Dependent origination (pratītya-samutpāda): This complex teaching explains how living beings come to be. It shows how they are shaped by different mind and body processes.
• Karma and rebirth: Actions that lead to a new life after death. This is part of an endless cycle of birth, death, and rebirth (saṃsāra).
• Nirvāṇa: The final goal, which ends all suffering.

These teachings are found in the Pāli Canon of Theravāda Buddhism and the Śālistamba Sūtra. Studies show that the Theravādin Majjhima Nikāya and the Sarvāstivādin Madhyama Āgama share most of these main Buddhist ideas. Early manuscripts also confirm these teachings are consistent with non-Mahayana Buddhism.

However, some scholars argue there are differences among these teachings. They question if certain ideas were taught in earliest Buddhism. For example, some think the idea of karma was not central to the Buddha's first teachings. Others disagree. There is also debate about whether insight alone led to freedom in early Buddhism. Some scholars believe dhyāna (meditation) was the original "freeing practice." They think insight as a separate path came later.

Some scholars believe early Buddhism focused on what ideas to reject rather than what to accept. Only knowledge that helps achieve freedom was valued. The many schools and groups of Buddhism started when people tried to explain the Buddha's hidden philosophy.

The Four Noble Truths and How Things Connect

The Four Noble Truths are a key part of the Buddha's teachings. They are explained in the Dharmacakrapravartana Sūtra.

The first truth is duḥkha, often called "suffering." This means life is always a bit unsatisfying. This feeling is not just physical pain or sadness. It is also a deep unease from knowing we will die and that everything changes (impermanence). Suffering also comes from bad events and not getting what we want.

The second truth is that this unease comes from certain conditions. The main ones are craving (taṇhā) and ignorance (avidyā).

The third truth is that when beings let go of craving and remove ignorance through wisdom, suffering stops (nirodhā).

The fourth truth is the Noble Eightfold Path. This path has eight practices that end suffering. They are: right view, right intention, right speech, right action, right livelihood, right effort, right mindfulness, and right samādhi (concentration). The highest goal is nirvāṇa. This means "extinguishing" greed, hatred, and delusion. These are the forces that power the cycle of birth and death (saṃsāra).

Nirvāṇa also means that after an enlightened being dies, there is no more rebirth. In earliest Buddhism, the idea of dependent origination (pratītya-samutpāda) likely only applied to mental processes. The Buddha saw the world as a flow of events, not fixed things. His theory says events happen because of certain conditions. They are all connected and depend on each other. Nothing is ever static or separate. For example, craving (taṇhā) always depends on sensations from the sense organs. Sensations depend on contact with our surroundings. The Buddha's idea of cause and effect is simple: "When this exists, that exists; when this arises, that arises; when this does not exist, that does not exist; when this stops, that stops." This shows how suffering arises and how it can be stopped.

To remove suffering caused by ignorance (avidyā), we need a deep understanding of reality (prajña). Thinking about ideas is important for this. But it is not enough to get rid of bad mental habits. That needs meditation combined with understanding. The Buddha's teachings say we need to train the mind in meditation. This helps us truly understand reality. Reality has the Three marks of existence: suffering, impermanence, and non-self (anātman). Understanding and meditation work together to clearly see (vipassanā) human experience. This leads to freedom.

No Permanent Self

The Five Aggregates (pañca khandha) according to the Pali Canon.
	form (rūpa)   4 elements (mahābhūta)         ↓     contact (phassa)     ↓ ↑   consciousness (viññāna)	→ ←       ←	mental factors (cetasika)     feeling (vedanā)       perception (sañña)       formation (saṅkhāra)
Form is derived from the Four Great Elements. Consciousness arises from other aggregates. Mental Factors arise from the Contact of Consciousness and other aggregates.
Source: MN 109 (Thanissaro, 2001)  |  diagram details

Gautama Buddha taught that things made of parts and living beings have no fixed essence. This means the self has no unchanging core (anātman). There is no part of a person that stays the same forever. There is no single "part of the person that explains who they are over time." This idea is different from the Upanishadic idea of an unchanging ultimate self (ātman) or an eternal soul. The Buddha believed that holding onto the idea of a permanent self in a changing world is the cause of suffering (duḥkha). It is the main block to reaching spiritual freedom (mokṣa).

The Buddha often used an argument based on observation against the idea of an unchanging self. He pointed out that the five aggregates of existence (skandhā) that make up a living being are always changing. This argument can be put simply:

• All mind and body processes (skandhā) are temporary.
• If there were a self, it would be permanent.
• There is nothing more to a person than these five aggregates.
• Therefore, there is no self.

This argument needs the idea that the five aggregates are all that make up a person. Otherwise, a self could exist outside these aggregates. Other Buddhist texts support this. For example, Saṃyutta Nikāya 22.47 says: "whatever holy people think of as self, they all think of the five grasping aggregates, or one of them."

This argument is well-known from the Anātmalakṣaṇa Sūtra. This text says that the seemingly fixed self is just what happens when we identify with the temporary aggregates of existence (skandhā). These are the changing processes that make up a person. In this view, a 'person' is just a name we give to a group of processes. An 'individual' is a concept we put on a stream of experiences. It is like how a chariot is just a name for its parts put together. This argument is based on what we observe: everything we see changes, especially when we look inward during meditation.

Another argument for non-self is the "argument from lack of control." This is based on the fact that we often want to change parts of ourselves. The "executive function" of the mind is what finds things unsatisfying and tries to change them. Also, in Indian philosophy, something cannot act on or control itself. A knife cuts other things, not itself. This means the self could never want to change itself. Also, in orthodox Hindu philosophy, the unchanging ultimate self (ātman) is perfectly happy and does not suffer. The Buddha used this idea to challenge the concept of self. This argument can be structured like this:

• If the self existed, it would be the part of the person that controls things.
• The self could never want to be changed (because it cannot control itself).
• Each of the five kinds of mind and body processes (skandhā) can be something one desires to change.
• There is nothing more to a person than these five aggregates.
• Therefore, there is no self.

This argument denies there is one permanent "controller" in a person. Instead, it sees a person as a set of constantly changing processes. These include actions that seek change and an awareness of that desire. Mark Siderits explains: "The Buddhist means that sometimes one part of the person controls, and sometimes another. This allows every part to be controlled without any one part always being the controller (and thus the self)."

The Buddha also extended his non-self idea to the Brahmanical belief that the unchanging ultimate self (ātman) was the whole world. He showed that an individual cannot experience the suffering of the whole world. He used the example of someone burning grass from a grove. A monk would not feel harmed because it is not "their self." In this example, the Buddha argues we do not directly experience the whole world. So, the self cannot be the whole world. In Buddhist texts, the Buddha lists six wrong views about the self:

"There are six wrong views: An unwise person might think of their body, feelings, perceptions, thoughts, or what they have seen, heard, or thought, as 'mine, me, my self.' The sixth is to believe: 'After death, I will become permanent, eternal, unchanging, and stay the same forever; and that is mine, that is me, that is my self.' A wise person sees all these ideas are wrong. So, they are not worried about something that does not exist."

The Buddha also argued that the world causes suffering. Since we cannot control the world as we wish, the world cannot be the self. The idea that "this universe is the self" is one of the six wrong views the Buddha rejected. He also rejected the monistic Hindu idea that "everything is one." The Buddha taught that understanding non-self leads to not being attached. This stops suffering. But ignorance (avidyā) about the true nature of personality (prajña) leads to more suffering.

How We Know Things

All schools of Indian philosophy recognize different ways to gain knowledge (pramāṇa). Many see the Vedas as a source of truth. But the Buddha rejected the authority of the Vedas. However, like others at his time, he agreed that having the right view (a correct understanding of reality) was important for spiritual freedom. This understanding was not mainly about the universe. It was about how suffering starts and stops in human experience. So, the Buddha's way of knowing is different from modern philosophy. It is mostly a solution to the basic human problem of suffering.

Gautama Buddha's way of thinking about knowledge is like empiricism. This means it is based on experiencing the world through the senses. The Buddha taught that observing through the six sense fields (āyatanā) was the right way to check any claims of knowledge. Some Buddhist texts say that "the All," or everything that exists, are these six sense fields. They say anyone trying to describe another "All" cannot, because "it is beyond reach." This suggests that for the Buddha, things in themselves are beyond what we can know.

Also, in the Kālāma Sutta, the Buddha tells villagers that the only good reason for beliefs is checking them in one's own experience. He also says to check with the experience of wise people. He rejects beliefs based on personal authority, sacred tradition, or any rationalism that builds complex theories. In the Tevijja Sutta (DN 13), the Buddha rejects the authority of Brahmins. He says none of them can prove they have experienced Brahman or that it exists. The Buddha also stressed that experience is the only way to check truth. In the Majjhima Nikāya (MN.I.265), he says:

"Monks, do you only speak that which is known by yourselves, seen by yourselves, found by yourselves?" "Yes, we do, sir." "Good, monks, That is how you have been instructed by me in this timeless teaching which can be realized and verified, that leads to the goal and can be understood by those who are intelligent."

The Buddha's standard for checking truth was also practical and aimed at saving people. For the Buddha, a belief is true only if it helps with Buddhist practice. This means it must lead to stopping craving. In the "Discourse to Prince Abhaya" (MN.I.392–4), the Buddha says a belief should only be accepted if it leads to good results. This idea of the Buddha, that what is true is what is useful, has been called a form of pragmatism by Western scholars. However, K. N. Jayatilleke argues that the Buddha's way of knowing can also be seen as a form of correspondence theory. This means truth matches reality. He also says that for the Buddha, something false cannot lead to the end of suffering.

Gautama Buddha told his followers not to argue just for the sake of arguing. This is useless and takes away from the main goals of awakening (bodhi) and freedom (mokṣa). Only philosophy and discussion that helps with freedom from suffering is important.

According to the Pāli Canon, the Buddha stayed silent when asked certain deep questions about the universe. He called these "unanswered questions" (avyākṛta). They included questions like whether the universe is eternal or not, if the body and self are one or separate, or if a person completely stops existing after death. In the Aggi-Vacchagotta Sutta, the Buddha said thinking about these questions led to "a thicket of views, a wilderness of views."

One reason for this silence is that such questions do not help with practical ways to achieve awakening. They also risk replacing real experience with just an idea of the teaching. The Buddha said the Dharma (his teaching) is not an end in itself. It is a practical tool. The Buddha used two stories to explain this: the 'Parable of the raft' and the Parable of the Poisoned Arrow. The Dharma is like a raft. It is only for crossing over to nirvana, not for holding onto (MN 22). Once you cross, you can leave the raft behind. It is also like medicine. The details of how you were shot by a poisoned arrow (like metaphysics) do not matter. What matters is removing the arrow and healing the wound (removing suffering). The Buddha was often called "the great physician" because his main goal was to cure human suffering.

However, sometimes arguing against a wrong idea can help someone escape error. The Buddha himself argued against some teachings. This shows that using logic and argument can be good.

After the Buddha's death, some Buddhists, like Dharmakirti, used the Buddha's sayings as strong proof, just like direct observation.

Beyond Words

Another reason the Buddha might have avoided deep questions about reality is that he saw ultimate reality and nirvana as beyond senses and ideas. So, language itself is not good enough to explain it. The Buddha's silence does not mean he disliked philosophy. It means he thought the answers to these questions could not be understood by those who were not enlightened. Dependent arising offers a way to understand reality. It does not rely on ideas about existence or non-existence. Instead, it is based on directly knowing things as they appear in the mind during meditation.

The Buddha in the earliest texts describes Dharma (truth) as "beyond reasoning." This means reasoning is a human way of seeing things. It is not how things truly are. Going "beyond reasoning" means understanding how reasoning works from the inside. It means removing the causes of future stress from it.

Right and Wrong Actions

The Buddha's ethics are based on the need to end suffering. They are also based on the law of karma. Buddhist ethics aim for well-being. They are also compared to virtue ethics. Damien Keown says that Buddhist Nirvana is like the Greek idea of Eudaimonia (human flourishing). Buddhist good actions and virtues get their value from how they lead us to or are part of the nirvanic life.

The Buddha taught five precepts for his followers, both lay people and monks. These include not drinking alcohol, not lying, not stealing, and not killing. The Buddha gave several reasons why someone should be ethical.

First, the universe is set up so that if you intentionally do something wrong, bad karma will result. So, it is best to avoid these actions. But the key word is intentionally. For the Buddha, karma is about intention. Unintentionally harming someone does not create bad karma. Unlike the Jains, who thought karma was a physical thing, for the Buddha, karma was a mental act of will.

Second, doing bad things on purpose strengthens bad mental habits. These habits keep people stuck in the cycle of rebirth. They also stop the process of freedom. Doing good actions on purpose helps purify the mind. This leads to nirvana, the highest happiness. From this view, bad acts are "unskillful" in our search for happiness. So, it is practical to do good.

Third, the idea of "no self" and our natural wish to end suffering leads to a final point. Since there is no fixed self, there is no reason to put our own well-being above others'. There is no ultimate reason to separate "my" suffering from someone else's. An enlightened person would work to end suffering for everyone, without thinking about separate people. So, anyone who is selfish does so out of ignorance about what a person truly is.

Buddhist Schools and Abhidharma

The main Indian Buddhist schools used a type of analysis called Abhidharma. This aimed to organize the teachings from the early Buddhist talks (sutras). Abhidharma analysis broke down human experience into tiny, momentary events called "dharmas." Dharmas are temporary and depend on other causes. They arise and pass away as part of a network of connected dharmas. They are never found alone.

The Abhidharma schools believed that the Buddha's teachings in the sutras were just conventional truths. But the Abhidharma analysis was the ultimate truth (paramattha sacca). It showed how things really are when seen by an enlightened being. The Abhidharma project is like a form of phenomenology (studying how things appear to us) or process philosophy (seeing reality as processes, not fixed things).

Abhidharma thinkers listed what they believed were all the dharmas. These are the ultimate phenomena, events, or processes (including physical and mental ones). They also explained how these dharmas relate to each other. In Abhidharma, the only thing truly real is the interaction of dharmas in a flow. Everything else is just a concept (paññatti) or a name.

This view is called "mereological reductionism." It means only the smallest parts are real, not the whole things. Abhidharmikas like Vasubandhu said that everyday things (tables, people) "disappear when analyzed." This analysis shows only a flow of events and their connections. Mainstream Abhidharmikas defended this against their Hindu rivals, the Nyaya school. The Nyaya school believed in fixed substances and universals (general ideas). Some Abhidharmikas, like the Prajñaptivāda, were also strict nominalists. They believed all things, even dharmas, were just concepts.

The Abhidharma Schools

An important Abhidhamma book from the Theravāda school is the Kathāvatthu ("Points of Controversy"). It is thought to be written by the scholar-monk Moggaliputta-Tissa. This text tries to disprove several ideas that appeared after the Buddha's death. Especially, it argues against the idea that 'all exists' (sarvāstivāda), the idea of momentariness (khāṇavāda), and the personalist view (pudgalavada). These were the main ideas that divided the Buddhist Abhidharma schools in India.

After being brought to Sri Lanka in the first century BCE, the Pali language Theravada Abhidhamma tradition was greatly shaped by Buddhaghosa (4th-5th century AD). He was the most important philosopher and writer for the Theravada school. Theravada philosophy was mostly written in Atthakatha (commentaries) and sub-commentaries on the classic Pali Abhidhamma texts. Abhidhamma study also included shorter summaries, like the Abhidhammattha-saṅgaha.

The Sarvāstivāda-Vaibhāṣika school was a major Buddhist philosophy in India. They were called this because they believed dharmas exist in all three times: past, present, and future. Their Abhidharma system started as a way to categorize mental events. But philosophers like Dharmatrata and Katyāyāniputra (who compiled the Mahāvibhāṣa) made it into a strong realism. This included a type of essentialism or substance theory. This realism was based on the nature of dharmas, called svabhava ("self-nature" or "intrinsic existence"). Svabhava is a kind of essence, but not fully independent, as all dharmas were said to depend on causes. The Sarvāstivāda system extended this realism across time. This meant they believed in a type of eternalism regarding time. So, their school name means "the view that everything exists." Vaibhāṣika remained important in North India during the medieval period.

Other Buddhist schools, like the Prajñaptivāda ("the nominalists") and the Caitika Mahāsāṃghikas, did not accept the idea of svabhava. So, not all Abhidharma texts support svabhava. For example, the Tattvasiddhi Śāstra by Harivarman (3rd-4th century CE) focuses on the emptiness (shunyata) of dharmas. This anti-essentialist nominalism was common among the Mahāsāṃghika groups. Another key idea of the Mahāsāṃghika tradition was its unique theory of consciousness. Many Mahāsāṃghika sub-schools believed in self-awareness (svasaṃvedana). This meant consciousness could be aware of itself and its object at the same time. Some also thought the mind's nature (cittasvabhāva) is pure, but it can be affected by outside problems.

The Theravādins and other schools, like the Sautrāntikas ("those who follow the sutras"), often criticized the Sarvāstivādins' ideas, especially their view of time. A major figure in this debate was the scholar Vasubandhu. He was a Sarvāstivādin monk but was also influenced by the Sautrantika school. He criticized the "all exists" theory and argued for philosophical presentism (only the present exists) in his book, the Abhidharmakośa. This book is the main Abhidharma text used in Tibetan and East Asian Buddhism today. The Theravāda also believes that dharmas only exist in the present.

The Theravāda way of presenting Abhidharma is less about what truly exists (ontology) than the Sarvāstivāda view. It is more about how things appear to us (phenomenology). So, for Theravādins, the concept of svabhava (Pali: sabhava) is more about a certain quality of a dharma, rather than a fixed essence. As scholar Y. Karunadasa writes, the Pali tradition uses sabhava "for definition and description." But ultimately, each dhamma (particular event) is not a single, separate existence. Karunadasa says Theravada Abhidhamma does not believe in many separate existing things (ontological pluralism). But it is also not monism (one underlying reality). Instead, dharmas are just processes that happen "because of many conditions working together." Karunadasa also calls the Theravada system "critical realism." This means it sees the basic existing things as many simple dhammas. It also accepts that an outside world truly exists independently of our minds.

Another important idea held by some Sarvāstivādins, Theravādins, and Sautrāntikas was "momentariness" (Skt., kṣāṇavāda). This idea said that dhammas only last for a tiny moment (ksana) after they appear. The Sarvāstivādins saw these 'moments' like tiny atoms, the smallest possible length of time. They also developed a theory of material atoms. It was a big challenge for the Sarvāstivāda to fit this idea with their belief that things exist in all three times. The Theravādins first rejected this idea. But later, Sri Lankan Theravādins adopted momentariness for mental dhammas (but not physical ones). It might have been introduced by Buddhagosa.

All Abhidharma schools also developed complex ideas about how things cause and condition each other. Another major project was explaining perception. Some schools, like the Sarvastivadins, explained perception as a type of realism. Others, like the Sautrantikas, preferred representationalism. They believed we only see objects indirectly. The Sautrāntikas used the "time-lag argument" for this view. Mark Siderits explains: "The idea is that there is a tiny gap between when a sense touches an object and when we become aware of it. So, what we are aware of cannot be the external object, because it no longer exists." This is linked to the idea of extreme momentariness.

One major idea rejected by all the schools above was the view of the Pudgalavadin or 'personalist' schools. They seemed to believe there was a kind of 'personhood' that was truly real and could not be broken down into the five aggregates. This was a controversial claim. Other Buddhists at the time believed that a personality was just a concept (prajñapti) and only real in a conventional way.

Indian Mahāyāna Philosophy

Around the 1st century BCE, a new set of texts appeared in Indian Buddhist thought called Mahāyāna (Great Vehicle). This would slowly become the main type of Indian Buddhist philosophy. During the medieval period, Buddhist philosophy grew in large monastery-universities like Nalanda and Vikramasila. These places became major centers for learning and debate. Mahāyāna philosophers continued the work of Abhidharma. But they also criticized it and brought in many new ideas. Since Mahāyāna believed in a practical idea of truth (teachings are "true" if they are spiritually helpful), these new ideas were seen as 'skillful means' (upaya).

Mahayana also promoted the bodhisattva ideal. This includes having compassion for all living beings. A Bodhisattva chooses to stay in samsara (the cycle of birth and death) to help all other suffering beings.

Major Mahayana philosophical schools include Prajñaparamita, Madhyamaka, Yogācāra, and Tathagatagarbha.

Prajñāpāramitā and Madhyamaka

The earliest Prajñāpāramitā-sutras ("perfection of insight" sutras) (around 1st century BCE) stress the shunyata (emptiness) of all things. This is a strong idea that nothing has a true, fixed essence. It sees all things as like illusions or dreams, without any basic nature. Prajñāpāramitā is said to be a special spiritual knowledge of ultimate reality. This reality is empty of any essence or foundation, like a mirage.

So, the Diamond Sutra (Vajracchedikā Prajñāpāramitā Sūtra) says: "All conditioned phenomena Are like a dream, an illusion, a bubble, a shadow, Like dew or a flash of lightning; Thus we shall perceive them."

The Heart Sutra famously states the emptiness (shunyata) of all things: "Oh, Sariputra, form does not differ from emptiness, and emptiness does not differ from form. Form is emptiness and emptiness is form; the same is true for feelings, perceptions, volitions and consciousness."

The Prajñāpāramitā texts also say this applies to everything, even Buddhahood. The goal for a Buddhist in these texts is to awaken to the perfection of wisdom ("prajñāpāramitā"). This is a wisdom that does not use concepts. It knows the emptiness of all things but is not attached to anything, not even the idea of emptiness itself.

The Prajñāpāramitā teachings are linked to the philosopher Nāgārjuna (around 150 – 250 CE) and the Madhyamaka (Middle Way) school. Nāgārjuna was one of the most important Indian Mahayana thinkers. He gave the classic arguments for why all dharmas are empty. He attacked the idea of essentialism found in Abhidharma schools and Hindu philosophy. He did this in his main work, The Root Verses on the Middle Way (Mūlamadhyamakakārikā). In this book, Nagarjuna uses reductio ad absurdum arguments. This means he shows that if you assume something is true, it leads to a ridiculous conclusion. He uses this to disprove ideas that assume a fixed essence (svabhava), dravya (substances), or any theory of fixed existence. He covers topics like causation, movement, and the senses.

Nāgārjuna said there is a direct link between, and even identity of, dependent origination, non-self (anatta), and emptiness (śūnyatā). He pointed out that the early Buddhist idea of dependent origination means there is no fixed self underlying things. So, things have no independent existence. This state is called śūnyatā (emptiness of a nature or essence).

Later Madhyamaka philosophers built on Nāgārjuna's ideas. They defended Madhyamaka against their opponents. These included Āryadeva (3rd century CE), Nāgārjuna's student; Candrakīrti (600–650), who wrote an important commentary; and Shantideva (8th century), a key Mahayana ethicist.

The writer Buddhapālita (around 470–550) is seen as the start of the 'prāsaṅgika' approach. This approach criticizes essentialism only through showing it leads to absurd conclusions. He was criticized by Bhāvaviveka (around 500 – 578). Bhāvaviveka argued for using logical arguments to positively prove emptiness. These two approaches were later called the prāsaṅgika and the svātantrika by Tibetan philosophers.

In China, the Madhyamaka school (known as Sānlùn) was started by Kumārajīva (344–413 CE). He translated Nagarjuna's works into Chinese.

Yogācāra

The Yogācāra school (meaning 'Yoga practice') was a Buddhist philosophy that appeared between the 2nd and 4th centuries CE. It is linked to the philosophers and brothers Asanga and Vasubandhu. It is also linked to sutras like the Sandhinirmocana Sutra and the Lankavatara Sutra. The main idea of Yogācāra is vijñapti-mātra, often translated as "impressions only" or "appearance only." This has been seen as a type of Idealism (reality is mind-based) or Phenomenology (study of experience). Other names for Yogācāra are 'vijñanavada' (the doctrine of consciousness) and 'cittamatra' (mind-only).

Yogācāra thinkers like Vasubandhu argued against the existence of outside objects. They pointed out that we only ever have access to our own mental impressions. So, our idea that outside objects exist is based on wrong logic. Vasubandhu's Triṃśikā-vijñaptimātratā (The Proof that There Are Only Impressions in Thirty Verses), starts like this: "I. This [world] is nothing but impressions, since it manifests itself as an unreal object, Just like the case of those with cataracts seeing unreal hairs in the moon and the like."

According to Vasubandhu, all our experiences are like seeing hairs on the moon when we have cataracts. We project our mental images onto something "out there," but those things are not really there. Vasubandhu then uses the dream argument to show that mental impressions do not need outside objects to (1) seem to be in a place and time, (2) seem to be shared by others, and (3) seem to follow cause-and-effect rules. The fact that purely mental events can have effects and be shared is shown by shared hallucinations created by the karma of certain beings. After arguing that "impressions-only" can explain our daily experience, Vasubandhu then uses parsimony. This means that since we do not need the idea of outside objects to explain reality, we can get rid of those extra ideas. They are likely just mental additions to our ideas of reality. Yogācārins like Vasubandhu also attacked the realist ideas of Buddhist atomism and the Abhidharma idea of svabhava. He argued that atoms, as atomists saw them (undividable), could not come together to form bigger things. So, they were illogical ideas.

For Vasubandhu, shared reality is the way different mental streams and their karma interact. It does not include any outside physical objects. The spiritual importance of this idea is that by removing the idea of an outside world, it also weakens the 'inner' sense of self as an observer separate from the outside world. To remove the idea of inner and outer is also to remove the sense of self and other.

Besides its defense of an idealistic view of reality and its attacks on realism, Yogācāra also developed a new theory of mind. This was based on the Eight Consciousnesses. It included the new idea of the subliminal storehouse consciousness (Skt: ālayavijñāna).

Yogācāra thinkers also explained ultimate reality using three basic modes or "natures" (svabhāva). This idea is central to their view of the ultimate and their understanding of emptiness (śūnyatā).

The Dignāga-Dharmakīrti Tradition

Dignāga (around 480–540) and Dharmakīrti (around 6th-7th century) were Buddhist philosophers. They developed a system of how we know things (epistemology) and logic. They did this in their debates with Brahmin philosophers to defend Buddhist teachings. This tradition is called "those who follow reasoning." They were linked to the Yogacara and Sautrantika schools. They defended ideas from both.

Dignāga had a huge impact. After him, all Buddhist and Sanskrit philosophers in India focused more on defending their ideas with clear theories of knowledge.

The "School of Dignāga" includes later philosophers like Santabhadra and Dharmottara (8th century). The epistemology they developed says there are only two ways to gain knowledge (pramana): "perception" (pratyaksa) and "inference" (anumāṇa). Perception is a direct, non-conceptual awareness of specific things. Inference is based on reason, language, and concepts.

These Buddhist philosophers supported the idea of momentariness. They also supported the Yogācāra "awareness only" view, the reality of specific things, atomism, nominalism, and the self-aware nature of consciousness. They attacked Hindu ideas of God, universals, the authority of the Vedas, and the idea of a permanent soul.

Later Yogācāra Ideas

After Asanga and Vasubandhu, the Yogācāra school went in different directions. One branch focused on how we know things (epistemology), which became the school of Dignaga. Another branch focused on expanding Yogācāra's ideas about reality and philosophy. This tradition includes figures like Dharmapala of Nalanda and Śīlabhadra (a top scholar at Nalanda). Yogācārins like Paramartha brought the school to China. There, it is known as Wéishí-zōng. An important Chinese Yogācāra text is Xuanzang's Cheng Weishi Lun, or "Discourse on the Establishment of Consciousness Only."

A later development was a mix of Yogācāra and tathāgatagarbha thought. This group adopted the idea of tathāgatagarbha (the buddha-womb or "buddha-within") from various tathāgatagarbha sutras. This mixed school eventually said that tathāgatagarbha was the pure part of the storehouse consciousness. Key texts for this school include the Laṅkāvatāra Sūtra and the Mahayana Awakening of Faith. One key figure was Paramārtha, an Indian monk who was an important translator in China. He taught a new idea of a "stainless consciousness" (amala-vijñāna), a pure wisdom in all beings. He said this was the same as buddha-nature. This combined tradition also became important in later Indian Buddhism.

Another later development was combining Yogācāra with Madhyamaka. Jñānagarbha (8th century) and his student Śāntarakṣita (725–788) brought together Yogacara, Madhyamaka, and the Dignaga school of epistemology. This mix is called Yogācāra-Svatantrika-Mādhyamika. Śāntarakṣita also helped bring Buddhism to Tibet. His students included Haribhadra and Kamalaśīla. This philosophical tradition is important in Tibetan Buddhist thought.

A big debate among later Yogācāra philosophers was between those who thought mental appearances were false (alikākāravāda) and those who thought they were true (Satyākāravāda). The main question was whether mental images or "aspects" (ākāra) are real or not. The Satyākāravāda group, like Jñānaśrīmitra, believed images in consciousness are real because they come from real consciousness. But Alikākāravāda defenders, like Ratnākaraśānti, argued that mental appearances do not really exist and are false or illusory. For them, the only real thing is a pure, self-aware consciousness that has no images.

Buddha-Nature Thought

The tathāgathagarbha sutras say that a real potential for awakening is in every living being. This was a change from the usual negative way of describing things in Buddhism. These texts tried to explain Buddhist teachings using positive language. This was to stop people from thinking Buddhism was about nothingness. These sutras say that the perfect wisdom of "not-self" is the true self (atman). The word "self" is used in a special way in these sutras. The "true self" is described as the perfection of the wisdom of not-self. The final goal is described with positive words that were used by other philosophers. But here, they describe the positive realities of Buddhahood.

Perhaps the most important Indian text for this teaching is the Ratnagotravibhāga (5th century CE). This book brought together all the main ideas of tathāgatagarbha. The Ratnagotravibhāga sees tathāgatagarbha as a natural quality in all things. It is everywhere, without concepts, free of suffering, and naturally joyful. It also describes buddha nature as “the naturally pure nature of the mind.” In many later Indian texts, tathāgathagarbha is also linked to the idea of the luminous mind (prabhasvara-citta). This old idea says the mind is naturally pure, and problems are just temporary. The Ratnagotravibhāga describes this pure nature as: unconditioned, unborn, eternal, unchanging, and permanent.

Some scholars say tathāgatagarbha does not mean a real self. Instead, it is a positive way to talk about emptiness. It shows the potential to become a Buddha through Buddhist practices. In this view, the purpose of tathāgatagarbha is to help people achieve freedom, not to describe what truly exists.

Vajrayāna Buddhism

Vajrayāna (also called Mantrayāna or Esoteric Buddhism) is a Mahayana Buddhist tradition. It is linked to texts called Buddhist Tantras, which became very important in India by the 8th century. By this time, Indian Tantric scholars were writing philosophical defenses and explanations of Buddhist tantric systems. They wrote commentaries on key tantras like the Guhyasamāja Tantra.

Vajrayāna's view was based on earlier Madhyamaka, Yogacara, and Buddha-nature ideas. But it saw itself as a faster way to freedom. It had many skillful methods (upaya) of tantric ritual. The need to explain and defend the Tantras came from the unusual nature of their rituals. These included secret mantras, complex visualizations of mandalas with wrathful deities, and other practices that were new or different from traditional Buddhist practice.

The defense of these tantric practices is based on the idea of transformation. This means negative mental factors and physical actions can be changed in a ritual setting.

Another way of explaining Buddhist Tantric texts, like the Vimalaprabha, is to see taboo or unethical statements as metaphors for tantric practice. For example, in the Vimalaprabha, "killing living beings" means stopping the breath at the top of the head.

Douglas Duckworth notes that Vajrayāna philosophy sees the body and the universe as already containing wisdom and divinity. Freedom (nirvana) and Buddhahood are not seen as something outside the body or in the future. They are present now and can be reached through tantric practices like deity yoga. So, Vajrayāna is also called the "resultant vehicle." It relies on the idea that the goal (freedom) is already present in all beings. Duckworth calls Vajrayāna's view a form of pantheism. This means the belief that every existing thing is divine and that all things show some kind of unity.

Major Indian Tantric Buddhist philosophers like Buddhaguhya and Ratnākaraśānti wrote tantric texts and commentaries. Others like Vajrabodhi brought tantra to Tang China. Tantric philosophy continued to grow in China and Japan.

In Tibet, philosophers like Sakya Pandita and Tsongkhapa continued the tradition of Buddhist Tantric philosophy.

Tibetan Buddhist Philosophy

Tibetan Buddhist philosophy mostly continues and refines the Indian Mahayana philosophical traditions. The first efforts of Śāntarakṣita and Kamalaśīla brought their scholarly tradition to Tibet.

Early Tibetan Buddhist philosophers focused on translating Indian philosophical books and writing commentaries. This was from the 8th to the 10th century. Early Tibetan thinkers were greatly influenced by Dharmakirti.

The 12th and 13th centuries saw the translation of Chandrakirti's works. His ideas spread in Tibet through scholars like Patsab Nyima Drakpa. This led to the Tibetan debate between the prasangika and svatantrika views, which continues today. The main disagreement is about using reasoned argument. For Śāntarakṣita's school, reason helps understand emptiness. Then, through meditation, one can reach a wisdom that does not need reason. But Chandrakirti rejects this. He says meditation on emptiness cannot involve any object. For him, reason's role is only to deny. Reason is used to deny any idea of fixed essence. Then, reason itself must also be denied.

Another important figure from this early period is Mabja Jangchub Tsöndrü (died 1185). He wrote an important commentary on Nagarjuna's Mūlamadhyamakakārikā. Mabja tried to find a middle ground between different views. His work influenced later Tibetan Madhyamikas.

There are different Tibetan Buddhist schools. According to Georges B.J. Dreyfus, the Sakya school mostly holds an anti-realist view. This means they see conventional truth as an illusion. The Gelug school tends to defend a form of realism. They accept that conventional truth is real in some way, but it depends on other things. The Kagyu and Nyingma schools also tend to follow Sakya anti-realism.

Shentong and Buddha Nature

The 14th century saw more interest in the Buddha nature texts. This is seen in the work of the third Kagyu Karmapa Rangjung Dorje (1284–1339). His book "Profound Inner Meaning" describes ultimate nature as Buddha nature. This is the basis for nirvana and samsara. It is bright and empty in its essence, beyond thought.

One of the most important thinkers on buddha-nature in Tibet was Dölpopa Shérap Gyeltsen (around 1292–1361). From the Jonang school, Dölpopa developed a view called shentong ('other emptiness'). This was based on earlier Yogacara and Buddha-nature ideas from India. The shentong view says that Buddhahood is already present in all living beings. It is an eternal, everywhere, non-dual wisdom. This view says that all temporary things are empty of fixed existence. But the ultimate reality, the buddha-wisdom, is not empty of its own fixed existence.

According to Dölpopa, all beings have the Buddha nature. This non-dual wisdom is real, unchanging, permanent, unconditioned, eternal, joyful, and compassionate. This ultimate buddha wisdom is "uncreated and indestructible, unconditioned and beyond the chain of dependent origination." It is the basis for both samsara and nirvana. Dolpopa's shentong view also taught that ultimate reality was truly a "Great Self" or "Supreme Self."

The shentong view influenced philosophers from other schools, like Nyingma and Kagyu thinkers. But it was also criticized by some as being too similar to the Hindu idea of Atman. The Shentong philosophy was also taught in Tibet and Mongolia by later Jonang scholars. In the late 17th century, the Jonang order was attacked by the 5th Dalai Lama. Most of their monasteries were converted to the Gelug order.

Gelug School

Je Tsongkhapa (1357–1419) founded the Gelug school of Tibetan Buddhism. This school became very powerful in Tibet through the Dalai Lama. It is the main supporter of the Prasaṅgika Madhyamaka view. Tsongkhapa's work is influenced by Candrakirti and Dharmakirti. Gelug philosophy is based on studying Madhyamaka texts and Tsongkhapa's works, as well as formal debate.

Tsongkhapa defended Prasangika Madhyamaka as the highest view. He criticized the svatantrika position. Tsongkhapa argued that because svatantrika establishes things by their own qualities, they do not fully understand the emptiness of things. So, they do not reach the same understanding. Following Chandrakirti, Tsongkhapa rejected the Yogacara teachings, even as a temporary step. Tsongkhapa also criticized Dolpopa's Shengtong view. He saw it as dangerously absolute and not following the middle way. Tsongkhapa found two main problems in how Madhyamika was understood: under-negation (of fixed essence), which could lead to absolutism, and over-negation, which could lead to nihilism.

Tsongkhapa's solution was to use logical reasoning only within the conventional world of the two truths. This allowed for using reason for ethics, monastic rules, and a conventional realism about knowledge. But he held that from the view of ultimate truth, all things (including Buddha nature and Nirvana) are empty of fixed existence. True freedom is this understanding of emptiness.

Sakya scholars like Rongtön and Gorampa disagreed with Tsongkhapa. They argued that the prasangika-svatantrika difference was just for teaching. Gorampa also criticized Tsongkhapa's realism. He argued that the structures that make an empty object seem conventionally real disappear under analysis. Tsongkhapa's students defended a realism about knowledge against the Sakya scholars' anti-realism.

Sakya School

Sakya Pandita (1182–1251) was a 13th-century leader of the Sakya school and ruler of Tibet. He was also one of the most important Buddhist philosophers in Tibet. He wrote about logic and how we know things. He promoted Dharmakirti's Pramanavarttika as central to scholarly study. Sakya Pandita's 'Treasury of Logic on Valid Cognition' explained the classic Sakya anti-realist view of knowledge. He argued that concepts like universals are not known through valid knowledge. So, they are not real objects of knowledge. Sakya Pandita also criticized ideas of sudden awakening.

Later Sakya scholars like Gorampa (1429–1489) and Sakya Chokden (1428–1507) developed and defended Sakya anti-realism. They are seen as the main interpreters and critics of Sakya Pandita's philosophy. Sakya Chokden also criticized Tsongkhapa's understanding of Madhyamaka and Dolpopa's Shentong. In his Definite ascertainment of the middle way, Chokden said Tsongkhapa's view was too focused on logic. He felt it was still caught up in thinking about ultimate reality, which is beyond language. Sakya Chokden's philosophy tried to bring together the views of Yogacara and Madhyamaka. He saw them both as valid and working together. Madhyamaka removes the mistake of seeing what is unreal as real. Yogacara removes the mistake of denying Reality.

Similarly, the Shentong and Rangtong views are seen as complementary by Sakya Chokden. Rangtong negation helps cut through all clinging to wrong views. Shentong is better for describing and improving meditation experience. So, for Sakya Chokden, the same understanding of ultimate reality can be reached and described in two different but compatible ways.

Nyingma School

The Nyingma school is greatly influenced by the view of Dzogchen (Great Perfection) and its Tantric texts. Longchenpa (1308–1364) was a major philosopher of the Nyingma school. He wrote many books on the Tibetan practice of Dzogchen and on Buddhist Tantra. These include the Seven Treasures. Longchenpa's works explain Dzogchen philosophically. They defend Dzogchen in light of the sutras and give practical instructions. For Longchenpa, the basis of reality is luminous emptiness, rigpa ("knowledge"), or buddha nature. This basis is also the link between sutra and tantra. Longchenpa's philosophy aimed to show the positive sides of Buddha nature thought. He wanted to do this without falling into the extreme ideas of Dolpopa. For Longchenpa, the basis for Dzogchen and Tantric practice is the "Ground" or "Basis" (gzhi). This is the natural Buddha nature, "the pure reality that is unconditioned and naturally present." It is "free from all extremes."

Rimé Movement

The 19th century saw the rise of the Rimé movement (non-sectarian). This movement aimed to push back against the powerful Gelug school's criticisms of other schools. It sought to develop a more open system of study. Jamyang Khyentse Wangpo (1820–1892) and Jamgön Kongtrül (1813–1899) started Rimé. The Rimé movement became important when the religious climate in Tibet was very divided. The goal of the movement was "a push towards a middle ground where the various views and styles of the different traditions were appreciated for their individual contributions rather than being refuted, marginalized, or banned."

Philosophically, Jamgön Kongtrül said Shentong was compatible with Madhyamaka. Another Rimé scholar, Jamgon Ju Mipham Gyatso (1846–1912), criticized Tsongkhapa from a Nyingma perspective. Mipham argued that the middle way is Unity. This means that from the ultimate view, the difference between living beings and Buddhas also disappears. Mipham also supported the view of rangtong (self emptiness).

The later Nyingma scholar Botrul (1894–1959) classified the main Tibetan Madhyamaka positions. These were shentong (other emptiness), Nyingma rangtong (self emptiness), and Gelug bdentong (emptiness of true existence). The main difference between them is what they "negate." Shengtong says that unreal experience is empty. Rangtong negates any conceptual reference. Bdentong negates any true existence.

The 14th Dalai Lama was also influenced by this non-sectarian approach. He studied under teachers from all major Tibetan Buddhist schools. His philosophical position is that the different views on emptiness work together:

"There is a tradition of making a distinction between two different perspectives on the nature of emptiness: one is when emptiness is presented within a philosophical analysis of the ultimate reality of things, in which case it ought to be understood in terms of a non-affirming negative phenomena. On the other hand, when it is discussed from the point of view of experience, it should be understood more in terms of an affirming negation – 14th Dalai Lama"

East Asian Buddhism

Tiantai School

The Buddhist schools in China before Tiantai were mostly direct copies from India. They had few changes to their basic ideas. The Tiantai school, founded by Zhiyi (538–597), was the first truly unique Chinese Buddhist philosophy. Tiantai aimed to bring all Buddhist teachings into one complete system. This was based on the ekayana ("one vehicle") teaching in the Lotus Sutra .

Tiantai's view of reality is a complete holism. It sees every event (dharma) as shaped by and part of the whole of reality. Every moment of experience reflects every other. So, suffering and nirvana, good and bad, Buddhahood and evil, are all "inherently included" in each other.

Tiantai's view of reality is in its teaching of the "three truths." This is an expansion of the Mādhyamaka two truths idea. The three truths are: the conventional truth of how things appear, the truth of emptiness, and the third truth of 'the exclusive Center' or middle way. This third truth is the Absolute. It says that nothing is "Neither-Same-Nor-Different" than anything else. Instead, each 'thing' is the absolute whole of all things appearing as a part. Everything contains everything else. Everything reflects "The Ultimate Reality of All Appearances." Each thought "contains three thousand worlds." This view allows Tiantai to say things that seem strange, like "evil is always part of the highest good, Buddhahood." Also, in Tiantai, nirvana and samsara are ultimately the same. Zhiyi writes, "a single, pure reality is all there is – no entities whatever exist outside of it."

While Zhiyi wrote "one thought contains three thousand worlds," this does not mean idealism (reality is only in the mind). According to Zhiyi, "the objects of the [true] aspects of reality are not something produced by Buddhas, gods, or men. They exist inherently on their own and have no beginning." This is a type of realism. It sees the mind as real as the world, connected to it and inseparable from it. In Tiantai thought, ultimate reality is simply the world of connected events or dharmas.

Other key figures of Tiantai thought are Zhanran (711–782) and Siming Zhili (960–1028). Zhanran developed the idea that non-living things have buddha nature. This is because they also reflect the Absolute. In Japan, this school was known as Tendai. It was brought to Japan by Saicho. Tendai thought is more mixed. It draws on Huayan and East Asian Esoteric Buddhism.

Huayan School

The Huayan school is another native Chinese system of thought. Huayan is known for the idea of "interpenetration." This is based on the Avataṃsaka Sūtra (Flower Garland Sutra). Huayan believes that all events (Sanskrit: dharmas) are deeply connected. They arise together, and every event contains all other events. Many metaphors are used to explain this. The first is Indra's net. This net has jewels that reflect all other jewels. And those reflections also contain every other reflection, endlessly. The second image is the world text. This sees the world as a huge text, as big as the universe. The words of the text are the events that make up the world. But every tiny part of the world contains the whole text within it. A Buddha's job is to reveal this text so beings can be free from suffering.

Fazang (643–712), a key Huayan thinker, wrote 'Essay on the Golden Lion'. This book has other metaphors for how reality interpenetrates. He also used the metaphor of a house of mirrors. Fazang introduced the difference between "the Realm of Principle" and "the Realm of Things." This idea was further developed by Cheng-guan (738–839) into the main Huayan idea of "the fourfold Dharmadhatu" (dharma realm). These are: the Realm of Principle, the Realm of Things, the Realm of the Noninterference between Principle and Things, and the Realm of the Noninterference of All Things. The first two are the universal and the particular. The third is how the universal and particular mix. The fourth is how all particulars mix. The third truth was explained with the metaphor of a golden lion: the gold is the universal, and the lion's shape is the particular.

Both Tiantai and Huayan believe all things interpenetrate and are connected. But their ideas about reality have some differences. Huayan's view of reality is influenced by Yogacara thought. It is closer to idealism. The Avatamsaka sutra compares the world of appearances to a dream, an illusion, or a magician's trick. The sutra says nothing has true reality, location, beginning, end, or fixed nature. The Avatamsaka also says that "The triple world is illusory – it is only made by one mind." Fazang agrees, writing, "outside of mind there is not a single thing that can be apprehended." Also, in Huayan thought, each mind creates its own world "according to their mental patterns." These worlds are "infinite in kind" and always appearing and disappearing. However, in Huayan, the mind is not real either; it is also empty. The true reality in Huayan, the "Principle," is like a mirror, and appearances are like reflections in the mirror. It is also compared to the ocean, and appearances to waves.

In Korea, this school was known as Hwaeom. It is seen in the work of Wonhyo (617–686). In Japan, Huayan is known as Kegon.

Chan and Japanese Buddhism

The philosophy of Chinese Chan Buddhism and Japanese Zen comes from various sources. These include Chinese Madhyamaka, Yogacara, the Laṅkāvatāra Sūtra, and the Buddha nature texts. An important idea in Chan is "sudden awakening." This is the idea that insight happens all at once. This view was promoted by Shenhui and is a main topic in the Platform Sutra, a key Chan scripture.

Huayan philosophy also influenced Chan. The idea of the Fourfold Dharmadhatu influenced the Five Ranks of Dongshan Liangjie (806–869), who founded a Chan lineage. Guifeng Zongmi, who was also a Huayan leader, wrote much about Chan philosophy and the Avatamsaka sutra.

Japanese Buddhism saw many new schools and ideas appear during the 6th and 7th centuries. This time is known as the six schools of Nara. The Kamakura period (1185–1333) also saw a lot of new thinking. During this time, Nichiren (1222–1282) made the teachings of the Lotus Sutra more available to people. He is very important because his teachings became a separate Buddhist group, one of the few major ones to start in Japan.

Also during the Kamakura period, the founder of Soto Zen, Dogen (1200–1253), wrote many books on Zen philosophy. The Shobogenzo is his main work. In Korea, Chinul was an important teacher of Seon Buddhism around the same time.

Esoteric Buddhism

Tantric Buddhism came to China in the 7th century. In China, this is called Mìzōng (密宗), or "Esoteric School." Kūkai (774–835) is a major Japanese Buddhist philosopher. He founded the Tantric Shingon school in Japan. He wrote about many topics like public policy, language, and religion. After studying in China, Kūkai brought different ideas together into a complete Shingon philosophy.

Kūkai's philosophy is based on the Mahavairocana Tantra and the Vajrasekhara Sutra. His Benkenmitsu nikkyôron explains the difference between common, mainstream Mahayana Buddhism and esoteric Tantric Buddhism. Kūkai provided the ideas for Tantric Buddhist practices. He connected the teachings of the sutras with tantric practices. At the heart of Kūkai's thought is the Trikaya doctrine, which says there are three "bodies of the Buddha."

According to Kūkai, esoteric Buddhism comes from the Dharmakaya (Japanese: hosshin, body of truth). This is linked to Vairocana Buddha. Hosshin is the absolute reality and truth made real. Hosshin cannot be fully put into words. But it can be experienced through esoteric practices like mudras and mantras. Mainstream Mahayana is taught by the historical Buddha. But it does not have ultimate reality as its source or the practices to experience the esoteric truth. For Shingon, from an enlightened view, the whole world itself is the teaching of Vairocana. The body of the world, its sounds and movements, is the body of truth. And it is also the same as the personal body of the cosmic Buddha. For Kūkai, the world, actions, people, and Buddhas are all part of Vairocana's cosmic talk. They are the truth being taught to its own forms. This is hosshin seppô ("the dharmakâya's teaching the Dharma"). It can be reached through mantra, which is Vairocana's cosmic language. It comes through cosmic vibration focused in sound. In a broad sense, the universe itself is a huge text expressing ultimate truth that must be "read."

Dainichi means "Great Sun." Kūkai uses this as a metaphor for the great original Buddha. His teaching and presence light up and fill everything, like the sun's light. This presence also means that every being already has access to the free state and Buddha nature. Because of this, it is possible to "become Buddha in this very body" (sokushinjôbutsu). This happens because of the non-dual relationship between the big picture of Hosshin and the small picture of the Shingon practitioner.

Kūkai's explanation of Shingon's "metaphysics" is based on three aspects of the cosmic truth or Hosshin: body, appearance, and function. The body is the physical and mental elements. These are the body and mind of the cosmic Buddha, and they are also empty (Shunyata). For Shingon, the physical universe contains connected mental and physical events. The appearance aspect is the form of the world. It appears as mandalas of connected realms. This is shown in mandala art like the Womb Realm mandala. The function is the movement and change in the world. This includes changes in forms, sounds, and thoughts. These forms, sounds, and thoughts are expressed by the Shingon practitioner in rituals. These rituals allow them to connect with Dainichi and reach freedom right now.

Modern Buddhist Philosophy

In Sri Lanka, Buddhist modernists like Anagarika Dharmapala (1864–1933) and Henry Steel Olcott tried to show that Buddhism was logical. They said it was compatible with modern scientific ideas like evolution. Dharmapala also argued that Buddhism had a strong social side. He saw it as liberal, caring, and democratic.

A later Sri Lankan philosopher, K. N. Jayatilleke (1920–1970), wrote an important modern book on Buddhist epistemology (how we know things). His student David Kalupahana wrote about the history of Buddhist thought.

In 20th-century China, the modernist Taixu (1890–1947) wanted to reform and revive Buddhism. He promoted the idea of a Buddhist Pure Land. He saw it not as a place in the sky, but as something that could be created here on Earth. This could be done through a "Buddhism for Human Life" that was free of supernatural beliefs. Taixu also wrote about the links between modern science and Buddhism. He believed that "scientific methods can only prove Buddhist teachings, they can never go beyond it." Like Taixu, Yin Shun (1906–2005) promoted a Humanistic Buddhism. This focused on helping people. His students have been important in spreading Humanistic Buddhism in Taiwan.

One of Tibetan Buddhism's most important modernist thinkers is Gendün Chöphel (1903–1951). He traveled in India and wrote many things. He promoted modern science to his Tibetan people. He also wrote Buddhist philosophical texts. Another very influential Tibetan Buddhist modernist was Chögyam Trungpa. His Shambhala Training aimed to fit modern Western ideas by offering a "secular enlightenment."

In Southeast Asia, thinkers like Buddhadasa and Thích Nhất Hạnh have promoted a philosophy of socially Engaged Buddhism. They have written about how Buddhism applies to society and politics. Also, Buddhist ideas about economic ethics have been explored. The study of the Pali Abhidhamma tradition continued to be important in Myanmar.

Japanese philosophy was greatly influenced by the Kyoto School. This group included Kitaro Nishida and Keiji Nishitani. These thinkers brought Buddhist ideas into conversation with Western philosophy, especially European phenomenologists and existentialists. The most important trend in Japanese Buddhist thought after the Kyoto school is Critical Buddhism. This argues against some Mahayana ideas like Buddha nature. In Nichiren Buddhism, the work of Daisaku Ikeda has also been popular.

The Japanese Zen Buddhist D.T. Suzuki (1870–1966) helped bring Zen Buddhism to the West. His Buddhist modernist works were very influential in the United States. Suzuki's view was a Zen Buddhism influenced by Romanticism. It promoted spiritual freedom as "a natural, freeing consciousness that goes beyond logical thought and social convention." This idea of Buddhism influenced the Beat writers.

Western Buddhist monks and priests have written texts on Buddhist philosophy. A key feature of Buddhist thought in the West has been a desire to talk with and combine with modern science and psychology. Many modern Buddhists like B. Alan Wallace and the 14th Dalai Lama have worked on this.

Another area of connection has been Buddhism and environmentalism. This is explored in the work of Joanna Macy. Another Western Buddhist philosophical trend has been to make Buddhism more secular, as seen in the works of Stephen Batchelor.

In the West, comparing Buddhist and Western thought started with Charles A. Moore. He founded the journal Philosophy East and West. Today, Western academics like Mark Siderits and Jay Garfield have written works that explain Buddhist ideas using Western philosophy.

Buddhism Compared to Other Philosophies

Scholars have found connections between ancient Buddhism and the ancient Greek philosophy of Pyrrhonism. The Greek philosopher Pyrrho spent 18 months in India. Ancient writers say his contact with Indian holy men led him to create his philosophy. Because Nāgārjuna's philosophy is very similar to Pyrrhonism, some scholars think Nāgārjuna was influenced by Greek Pyrrhonist texts brought to India.

Baruch Spinoza, though he believed in a permanent reality, said that all things we see are temporary. He thought sadness is overcome "by finding something to know that is not temporary, but is unchanging, permanent, everlasting." The Buddha taught that the only thing eternal is Nirvana. David Hume, after studying the mind, concluded that consciousness is made of fleeting mental states. Hume's Bundle theory is very similar to the Buddhist skandhas.

Arthur Schopenhauer's philosophy is like Buddhism in his belief that denying desires helps with suffering. Ludwig Wittgenstein's "language-game" is similar to the warning that thinking too much (papañca) stops understanding. This is found in the Buddhist Parable of the Poison Arrow. Friedrich Nietzsche, though he disliked Buddhism, had a similar view of the self as temporary. Heidegger's ideas on being and nothingness have been compared to Buddhism.

Another way to compare Buddhist thought with Western philosophy is to use the idea of the Middle Way in Buddhism. This can be a tool to judge Western philosophies. In a Buddhist view, all philosophies are seen as temporary ideas (ditthis) and should not be clung to.