Rationalism in the context of Reason

Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called the theory of knowledge, it explores different types of knowledge, such as propositional knowledge about facts, practical knowledge in the form of skills, and knowledge by acquaintance as a familiarity through experience. Epistemologists study the concepts of belief, truth, and justification to understand the nature of knowledge. To discover how knowledge arises, they investigate sources of justification, such as perception, introspection, memory, reason, and testimony.

The school of skepticism questions the human ability to attain knowledge, while fallibilism says that knowledge is never certain. Empiricists hold that all knowledge comes from sense experience, whereas rationalists believe that some knowledge does not depend on it. Coherentists argue that a belief is justified if it coheres with other beliefs. Foundationalists, by contrast, maintain that the justification of basic beliefs does not depend on other beliefs. Internalism and externalism debate whether justification is determined solely by mental states or also by external circumstances.

Pre-Socratic philosophy, also known as early Greek philosophy, is ancient Greek philosophy before Socrates. Pre-Socratic philosophers were mostly interested in cosmology, the beginning and the substance of the universe, but the inquiries of these early philosophers spanned the workings of the natural world as well as human society, ethics, and religion. They sought explanations based on natural law rather than the actions of gods. Their work and writing has been almost entirely lost. Knowledge of their views comes from testimonia, i.e. later authors' discussions of the work of pre-Socratics. Philosophy found fertile ground in the ancient Greek world because of the close ties with neighboring civilizations and the rise of autonomous civil entities, poleis.

Pre-Socratic philosophy began in the 6th century BC with the three Milesians: Thales, Anaximander, and Anaximenes. They all attributed the arche (a word that could take the meaning of "origin", "substance" or "principle") of the world to, respectively, water, apeiron (the unlimited), and air. Another three pre-Socratic philosophers came from nearby Ionian towns: Xenophanes, Heraclitus, and Pythagoras. Xenophanes is known for his critique of the anthropomorphism of gods. Heraclitus, who was notoriously difficult to understand, is known for his maxim on impermanence, ta panta rhei, and for attributing fire to be the arche of the world. Pythagoras created a cult-like following that advocated that the universe was made up of numbers. The Eleatic school (Parmenides, Zeno of Elea, and Melissus) followed in the 5th century BC. Parmenides claimed that only one thing exists and nothing can change. Zeno and Melissus mainly defended Parmenides' opinion. Anaxagoras and Empedocles offered a pluralistic account of how the universe was created. Leucippus and Democritus are known for their atomism, and their views that only void and matter exist. The Sophists advanced philosophical relativism. The Pre-Socratics have had significant impact on several concepts of Western philosophy, such as naturalism and rationalism, and paved the way for scientific methodology.

German philosophy, meaning philosophy in the German language or philosophy by German people, in its diversity, is fundamental for both the analytic and continental traditions. It covers figures such as Gottfried Wilhelm Leibniz, Immanuel Kant, Georg Wilhelm Friedrich Hegel, Karl Marx, Friedrich Nietzsche, Martin Heidegger, Ludwig Wittgenstein, the Vienna Circle, and the Frankfurt School, who now count among the most famous and studied philosophers of all time. They are central to major philosophical movements such as rationalism, German idealism, Romanticism, dialectical materialism, existentialism, phenomenology, hermeneutics, logical positivism, and critical theory. The Danish philosopher Søren Kierkegaard is often also included in surveys of German philosophy due to his extensive engagement with German thinkers.

Western esotericism, also known as the Western mystery tradition, is a wide range of loosely related ideas and movements that developed within Western society. These ideas and currents are united since they are largely distinct both from orthodox Abrahamic religion and Age of Enlightenment rationalism. It has influenced, or contributed to, various forms of Western philosophy, mysticism, religion, science, pseudoscience, art, literature, and music.

The idea of grouping a wide range of Western traditions and philosophies together under the term esotericism developed in 17th-century Europe. Various academics have debated numerous definitions of Western esotericism. One view adopts a definition from certain esotericist schools of thought themselves, treating "esotericism" as a perennial hidden inner tradition. A second perspective sees esotericism as a category of movements that embrace an "enchanted" worldview in the face of increasing disenchantment. A third views Western esotericism as encompassing all of Western culture's "rejected knowledge" that is accepted neither by the scientific establishment nor orthodox religious authorities.

A theory is in general any hypothesis or set of ideas about something, formed in any number of ways through any sort of reasoning for any sort of reason.

When applied to intellectual or academic situations, it is considered a systematic and rational form of abstract thinking about a phenomenon, or the conclusions derived from such thinking. It involves contemplative and logical reasoning, often supported by processes such as observation, experimentation, and research. Theories can be scientific, falling within the realm of empirical and testable knowledge, or they may belong to non-scientific disciplines, such as philosophy, art, or sociology. In some cases, theories may exist independently of any formal discipline.

Islamic philosophy is philosophy that emerges from the Islamic tradition. Two terms traditionally used in the Islamic world are sometimes translated as philosophy—falsafa (lit. 'philosophy'), which refers to philosophy as well as logic, mathematics, and physics; and kalam (lit. 'speech'), which refers to a rationalist form of Scholastic Islamic theology which includes the schools of Ash'arism, Maturidism and Mu'tazilism.

Early Islamic philosophy began with al-Kindi in the 2nd century of the Islamic calendar (early 9th century CE) and declined with Ibn Rushd (Averroes) in the 6th century AH (late 12th century CE), broadly coinciding with the period known as the Islamic Golden Age. The death of Ibn Rushd effectively marked the end of a specific discipline of Islamic philosophy usually called the Islamic peripatetic school, and philosophical activity declined significantly in the west of the Islamic world, including al-Andalus and the Maghreb.

In philosophy, empiricism is an epistemological view which holds that true knowledge or justification comes only or primarily from sensory experience and empirical evidence. It is one of several competing views within epistemology, along with rationalism and skepticism. Empiricists argue that empiricism is a more reliable method of finding the truth than purely using logical reasoning, because humans have cognitive biases and limitations which lead to errors of judgement. Empiricism emphasizes the central role of empirical evidence in the formation of ideas, rather than innate ideas or traditions. Empiricists may argue that traditions (or customs) arise due to relations of previous sensory experiences.

Historically, empiricism was associated with the "blank slate" concept (tabula rasa), according to which the human mind is "blank" at birth and develops its thoughts only through later experience.

Baruch (de) Spinoza (24 November 1632 – 21 February 1677), also known under his Latinized pen name Benedictus de Spinoza, was a philosopher of Portuguese-Jewish origin, who was born in the Dutch Republic. A forerunner of the Age of Enlightenment, Spinoza significantly influenced modern biblical criticism, 17th-century rationalism, and Dutch intellectual culture, establishing himself as one of the most important and radical philosophers of the early modern period. Influenced by Stoicism, Thomas Hobbes, René Descartes, Ibn Tufayl, and heterodox Christians, Spinoza was a leading philosopher of the Dutch Golden Age.

Spinoza was born in Amsterdam to a Marrano family that fled Portugal for the more tolerant Dutch Republic. He received a traditional Jewish education, learning Hebrew and studying sacred texts within the Portuguese Jewish community, where his father was a prominent merchant. As a young man, Spinoza challenged rabbinic authority and questioned Jewish doctrines, leading to his permanent expulsion from his Jewish community in 1656. Following that expulsion, he distanced himself from all religious affiliations and devoted himself to philosophical inquiry and lens grinding. Spinoza attracted a dedicated circle of followers who gathered to discuss his writings and joined him in the intellectual pursuit of truth.

A Treatise of Human Nature: Being an Attempt to Introduce the Experimental Method of Reasoning into Moral Subjects (1739–40) is a book by Scottish philosopher David Hume, considered by many to be Hume's most important work and one of the most influential works in the history of philosophy. The book has appeared in many editions since the death of the author in 1776.

The Treatise is a classic statement of philosophical empiricism, scepticism, and naturalism. In the introduction Hume presents the idea of placing all science and philosophy on a novel foundation: namely, an empirical investigation into human nature. Impressed by Isaac Newton's achievements in the physical sciences, Hume sought to introduce the same experimental method of reasoning into the study of human psychology, with the aim of discovering the "extent and force of human understanding". Against the philosophical rationalists, Hume argues that the passions, rather than reason, cause human behaviour. He introduces the famous problem of induction, arguing that inductive reasoning and our beliefs regarding cause and effect cannot be justified by reason; instead, our faith in induction and causation is caused by mental habit and custom. Hume defends a sentimentalist account of morality, arguing that ethics is based on sentiment and the passions rather than reason, and famously declaring that "reason is, and ought only to be the slave to the passions." Hume also offers a sceptical theory of personal identity and a compatibilist account of free will.

Existentialism is a family of philosophical views and inquiry that explore the human individual's struggle to lead an authentic life despite the apparent absurdity or incomprehensibility of existence. In examining meaning, purpose, and value, existentialist thought often includes concepts such as existential crises, angst, courage, and freedom.

Existentialism is associated with several 19th- and 20th-century European philosophers who shared an emphasis on the human subject, despite often profound differences in thought. Among the 19th-century figures now associated with existentialism are philosophers Søren Kierkegaard and Friedrich Nietzsche, as well as novelist Fyodor Dostoevsky, all of whom critiqued rationalism and concerned themselves with the problem of meaning. The word existentialism, however, was not coined until the mid 20th century, during which it became most associated with contemporaneous philosophers Jean-Paul Sartre, Martin Heidegger, Simone de Beauvoir, Karl Jaspers, Gabriel Marcel, Paul Tillich, and more controversially Albert Camus.

Henri-Louis Bergson (/ˈbɜːrɡsən, bɛərɡ-/; French: [bɛʁksɔn]; 18 October 1859 – 4 January 1941) was a French philosopher who was influential in the traditions of analytic philosophy and continental philosophy, especially during the first half of the 20th century until the Second World War, but also after 1966 when Gilles Deleuze published Le Bergsonisme.

Bergson is known for his arguments that processes of immediate experience and intuition are more significant than abstract rationalism and science for understanding reality. Bergson was awarded the 1927 Nobel Prize in Literature "in recognition of his rich and vitalizing ideas and the brilliant skill with which they have been presented". In 1930, France awarded him its highest honour, the Grand-Croix de la Legion d'honneur. Bergson's great popularity created a controversy in France, where his views were seen as opposing the "secular and scientific" attitude adopted by the Republic's officials.

Ash'arism (/æʃəˈriː/; Arabic: ٱلْأَشْعَرِيّةُ, romanized: al-Ashʿarīyya) is a school of theology in Sunni Islam named after Abu al-Hasan al-Ash'ari, a Sunni jurist, reformer (mujaddid), and scholastic theologian, in the 9th–10th century. It established an orthodox guideline, based on scriptural authority, rationality, and theological rationalism. It is one of the three main schools alongside Maturidism and Atharism.

Al-Ash'ari established a middle way between the doctrines of the Atharī and Muʿtazila schools of Islamic theology, based both on reliance on the sacred scriptures of Islam and theological rationalism concerning the agency and attributes of God. Ashʿarism eventually became the predominant school of theological thought within Sunnī Islam, and is regarded as the single most important school of Islamic theology in the history of Islam.

Maturidism (Arabic: المَاتُريدِيَّةُ, romanized: al-Māturīdiyya) is a school of theology in Sunni Islam named after Abu Mansur al-Maturidi. It is one of the three creeds of Sunni Islam alongside Ash'arism and Atharism, and prevails in the Hanafi school of jurisprudence.

Al-Maturidi codified and systematized the theological Islamic beliefs already present among the Ḥanafite Muslim theologians of Balkh and Transoxiana under one school of systematic theology (kalām); Abu Hanifa emphasized the use of rationality and theological rationalism regarding the interpretation of the sacred scriptures of Islam.

Mu'tazilism (Arabic: المعتزلة, romanized: al-muʿtazila, singular Arabic: معتزلي, romanized: muʿtazilī) is an Islamic theological school that appeared in early Islamic history and flourished in Basra and Baghdad. Its adherents, the Mu'tazilites, were known for their neutrality in the dispute between Ali and his opponents such as Mu'awiya after the death of the third caliph, Uthman. By the 10th century the term al-muʿtazilah had come to refer to a distinctive Islamic school of speculative theology (kalām). This school of theology was founded by Wasil ibn Ata.

The later Mu'tazila school developed an Islamic type of rationalism, based around fundamental principles: the oneness (Tawhid) and justice (Al-'adl) of God, human freedom of action, and the creation of the Quran. The Mu'tazilites are best known for rejecting the doctrine of the Quran as uncreated and co-eternal with God, asserting that if the Quran is the literal word of God, he logically "must have preceded his own speech". This went against a common Sunni position (followed by the Ashʿarī and Māturīdī) which argued that with God being all-knowing, his knowledge of the Quran must have been eternal, hence uncreated just like him. The school also worked to resolve the theological "problem of evil", arguing that since God is just and wise, he cannot command what is contrary to reason or act with disregard for the welfare of His creatures; consequently evil must be regarded as something that stems from errors in human acts, arising from man's divinely bestowed free will.The Mu'tazila opposed secular rationalism, but believed that human intelligence and reason allowed Man to understand religious principles; that good and evil are rational categories that could be "established through reason".

New Confucianism (Chinese: 新儒家; pinyin: Xīn Rújiā; lit. 'New Confucianism') is an intellectual movement of Confucianism that began in the early 20th century in Republican China, and further developed in post-Mao era contemporary China. It primarily developed during the May Fourth Movement. It is deeply influenced by, but not identical to, the neo-Confucianism of the Song and Ming dynasties.

It is a neo-conservative movement of various Chinese traditions and has been regarded as containing religious overtones; it advocates for certain Confucianist elements of society – such as social, ecological, and political harmony – to be applied in a contemporary context in synthesis with Western philosophies such as rationalism and humanism. Its philosophies have emerged as a focal point of discussion between Confucian scholars in mainland China, Taiwan, Hong Kong, and the United States.