Indonesian philosophy is a generic designation for the tradition of abstract speculation held by the people who inhabit the region now known as Indonesia. Indonesian philosophy is expressed in the living languages found in Indonesia (approximately 587 languages) and its national language Indonesian, comprising many diverse schools of thought with influences from Eastern and Western origins, and indigenous philosophical themes.

The term Indonesian philosophy originates from the title of a book written by M. Nasroen, in which he traced philosophical elements found in Indonesian culture. Since then, the term has been popular and inspired many later writers like Sunoto, Parmono, and Jakob Sumardjo. Sunoto established the nation's first philosophy department at Gadjah Mada University in Yogyakarta in August, 1967.

Sunoto, Parmona, and Sumardjo each defined the word Indonesian philosophy differently. Without clearly defining the word, M. Nasroen argued that Indonesian philosophy was neither Western nor Eastern. He pointed to core Indonesian concepts and practices such as mupakat, pantun-pantun, Pancasila, hukum adat, gotong-royong, and kekeluargaan. Sunoto also embraced a culturalist notion of Indonesian philosophy, calling it "the cultural richness of our own nation…contained in our own culture." Similarly, Parmono defined it as "thought or reflections…which are bound in adat as well as ethnic culture". Sumardjo wrote that Indonesian philosophy are "primordial thoughts" or "basic mindsets that structurise the whole culture of an ethnic group".

The writers above understand Indonesian philosophy as a part of culture and do not make a contrast between philosophy and cultural studies or anthropology. The Indonesian language initially had no word for philosophy as an entity separated from theology, art, and science. Instead, as argued by Sutan Takdir Alisjahbana, Indonesians have a generic word budaya or kebudayaan, which describes the totality of the manifestations of the life of a society. Philosophy, science, theology, religion, art and technology are at once manifestations of a society's life, which are included in the meaning of the word budaya. Indonesians usually use the word budayawan for their philosophers. Accordingly, to them, the scope of Indonesian philosophy only comprised those original notions of Indonesian cultural richness. This is understood by as "the poverty of the scope." If Indonesian philosophy only comprised those original ethnic philosophies, it would be very limited. Like other scholars, Hidayat widens the scope of Indonesian philosophy so as to include the adapted and "indigenized" philosophy as influenced by foreign philosophical traditions. This article employs the latter definition.

Schools of thought There are seven schools of thought developing in Indonesia. The categorization of schools is first based on the originality that a certain school contains (like "ethnic school"), secondly based on the influence of great world philosophies that a particular school absorbs and adapts to Indonesian philosophy (such as "Chinese school," "Indian school," "Islamic school," "Christian school," and "Western school"), and lastly based on a historical chronology (such as "the post-Soeharto school"). The following is a sketch of the Indonesian schools of thought and their main philosophers.

Ethnic school

This school takes Indonesian ethnic philosophies as its source of inspiration. Its assumption is mythologies, legends, folklores, the way an ethnic group builds its house and holds its ceremonies, literature it keeps, the epics the ethnic group writes, all bases foundation of its philosophy. This 'philosophy' cannot change; it remains the same, from the beginning to the end of the world, and it is also 'the Good'. It guides every member of the group to the origin of group creation on earth (in Javanese, sangkan) and the telos of the life the group reaches to (in Javanese, paran), so the member cannot go astray.

This school preserves Indonesian ethnic philosophies which are original, since the philosophies had been hold tight by ethnic members before they were encountered with later foreign philosophical traditions.

Most of the school’s proponents assume that today’s Indonesian people are in the position of being blind to their original values. Jakob Sumardjo, for instance, argued that most of today’s Indonesians …forget to preserve their original values and …forgetting the past, forgetting the origin, they are like amnesiac people... who …ignore their own national history…. Consequently, they are ‘alienated’; estranged from ‘their mother cultures’. The failure of Indonesian educational policy, to Jakob, is brought by this ‘blindness’ to Indonesian original culture. Therefore, the necessary task of this school of philosophy is to seek after, recall and revitalize the ethnic original values, since the values are ‘mothers’ (lokalitas ialah ibu manusia) and people are ‘fathers’ of existence (balita ialah bapak manusia).

The following are some philosophical notions which this school advocates:

Adat

For this school of thought, adat plays very important role. Adat is the main inspiration for ethnic philosophers, as it is the intellectual legacy which belongs to a particular ethnic group. Adat is inherited from an ethnic's forefathers to later generations of the ethnic group. Indonesians believe that adat is not a human creation, but the spirits and supernatural powers ruling the community. This adat is very different from what Englishmen call tradition, custom or convention today. Its meaning is not simply wider, but more particularly goes far deeper. It includes everything Englishmen call law nowadays; and it goes much further than law in determining the needs and the actions of individuals and the community. It ordains the ceremonies of marriage, birth and death, the times and the methods for sowing rice, building a house, praying for rain, and many other things. Economics, politics, philosophy and art all come within its sphere. Indeed, from one point of view, adat is simply a social expression of the community religion, in as much as it is not a human creation, and in its exercise men are still constantly watched over by the spirits and supernatural powers ruling community. Because the adat which regulates the entire life of the community is dominated by spirits and supernatural powers, that communal life is inevitably static and deeply conservative. Its roots lay in the obscurity of the past, when the ancestors laid down the adat once and for all, or as Minangkabau people say: It doesn't crack with the heat or rot in the rain. In such an environment the word 'old' has a special significance, denoting something venerable, sacred, powerful and full of wisdom.

Myths of Origin

Among intellectual legacy which the adat inherited to Indonesians is a set of myths of origin of creation. The myths are sung (and only recently written) in important ceremonies held on special occasions of birth, death, marriage, harvest festival, and so on. The Dayak-Benuaq tribe of East Kalimantan, for example, has a set of myths known as Temputn. This Temputn tells myths of origin of universe, world and sky, human and animal creation, plants, water, fire, rain, death, ancestor origin, and some social taboos. According to Temputn, far before humankind had been created, they were two families who inhabited the sky. Of the raw materials used by the ‘sky families’ to create the earth and the sky, finally the first human came into being. He was married to a woman, who was his own daughter, and had many children, some of whom later became seniangs—group of spirits who live in the heavens, responsible for the policing of the most important moral affairs and they are in charge of adat guardians. The seniangs can inflict punishments (curses) on the ‘incestuous’. Their children were not only the human race and spirits, but also animals like wildcats of the forest, bears, ancestor of deer, the pigs of the forest, forefathers of monkey, ancestor of bees, snakes, and many others.

Pantun

Pantun is original kind of poem created by Indonesians. It is a four-line poem that consists of two parts; the first two lines are called as sampiran and the second two lines as isi. The sampiran always provides an analogy for the isi, and it symbolizes a macrocosm for a microcosm. As the mythology went, humankind was made of materials from which 'the sky families' created the sky and the world, and pantun reflects this belief very clearly. The sampiran represents 'the sky and the world', while the isi signifies 'the humankind'. Both between sampiran and isi there must be logical correspondence, as they both are symbols of harmony of the nature and humankind. Below is an example of pantun:

Tujuh hari dalam hutan || Air tak minum, nasii tak magan || Sehari tiada padan tooan|| rasania susut tubum di badan

The sampiran which says (in English) seven days in deep forest || no drinking water, no eating rice must have logical correspondence with the isi, which says no meeting you Sir in a day || feels like the body becomes thinner and thinner. The sampiran says about the suffering one can feel when he is in a deep forest in seven days without drink and food, while the isi says about the suffering one can feel when he does not meet in a day the lover he really longs or yearns for. The sampiran, therefore, analogizes the isi in the suffering of the longing.

Pepatah

A pepatah is like a proverb or saying. These sayings are part of the adat in the sense that they give guidance and instruction to every member of a particular ethnic group to treat others well in the community. It is believed that pepatah were created by ancestors inspired by supernatural powers and spirits. The wording of a pepatah is taken from nature, which means that all guidance for people's life must be derived from the laws of nature. Nature has its own laws and it is people's obligation to submit to it. As the myth of origin told, humans were parts of nature; they were made of it, so they had to live in total submission to its laws.

Here are some examples of pepatah: dalam laut dapat diduga, dalam hati siapa tahu (we can assume the depth of the sea, but we cannot assume what is in people's hearts) teaches very clearly about the danger of assuming what is in people's hearts, for this knowledge can only be obtained by asking the people concerned, not by assuming; ada gula, ada semut (where there is sugar, there is ant) teaches the law of causality, in which an effect can be inferred if there is a cause; malu bertanya, sesat di jalan (if you are shy of asking questions, you will get lost in your way) teaches the importance of asking questions in the process of seeking after knowledge, and the like.

Adat Social Structure

It has been stated above that not only did adat include tradition, custom, convention and law, but it also included a kind of social structure. The social structure bound by a common adat was typified by small-scale communities of people in villages or of nomads wandering over a specific area. These communities were rather like miniature democratic republics. Their headmen were elected from the descendants of the oldest branch of the tribe, and they saw to the needs and interests of the community, assisted by a council of elders. Really important decisions were taken by collective deliberations, called as mupakat. Naturally in a democracy of this type, in which a premium is put on unanimity of opinions, the position of the balai was extremely important. This was the building in which meetings and discussions were held. We can think them as the centers of social life within these small communities.