Theory of forms in the context of "Republic (Plato)"

Plato (/ˈpleɪtoʊ/ PLAY-toe; Greek: Πλάτων, Plátōn; born c. 428–423 BC, died 348/347 BC) was an ancient Greek philosopher of Classical Athens who is most commonly considered the foundational thinker of the Western philosophical tradition. An innovator of the literary dialogue and dialectic forms, Plato influenced all the major areas of theoretical philosophy and practical philosophy, and was the founder of the Platonic Academy, a philosophical school in Athens where Plato taught the collection of philosophical theories that would later become known as Platonism.

Plato's most famous contribution is his Theory of Forms (or Ideas), which aims to solve what is now known as the problem of universals. He was influenced by the pre-Socratic thinkers Pythagoras, Heraclitus, and Parmenides, although much of what is known about them is derived from Plato himself.

In their most common sense, thought and thinking refer to cognitive processes that occur independently of direct sensory stimulation. Core forms include judging, reasoning, concept formation, problem solving, and deliberation. Other processes, such as entertaining an idea, memory, or imagination, are also frequently considered types of thought. Unlike perception, these activities can occur without immediate input from the sensory organs. In a broader sense, any mental event—including perception and unconscious processes—may be described as a form of thought. The term can also denote not the process itself, but the resulting mental states or systems of ideas.

A variety of theories attempt to explain the nature of thinking. Platonism holds that thought involves discerning eternal forms and their interrelations, distinguishing these pure entities from their imperfect sensory imitations. Aristotelianism interprets thinking as instantiating the universal essence of an object within the mind, derived from sense experience rather than a changeless realm. Conceptualism, closely related to Aristotelianism, identifies thinking with the mental evocation of concepts. Inner speech theories suggest that thought takes the form of silent verbal expression, sometimes in a natural language and sometimes in a specialized "mental language," or Mentalese, as proposed by the language of thought hypothesis. Associationism views thought as the succession of ideas governed by laws of association, while behaviorism reduces thinking to behavioral dispositions that generate intelligent actions in response to stimuli. More recently, computationalism compares thought to information processing, storage, and transmission in computers.

Essentialism is the view that objects have a set of attributes that are necessary to their identity. In early Western thought, Platonic idealism held that all things have such an "essence"—an "idea" or "form". In Categories, Aristotle similarly proposed that all objects have a substance that, as George Lakoff put it, "make the thing what it is, and without which it would be not that kind of thing". The contrary view—non-essentialism—denies the need to posit such an "essence". Essentialism has been controversial from its beginning. In the Parmenides dialogue, Plato depicts Socrates questioning the notion, suggesting that if we accept the idea that every beautiful thing or just action partakes of an essence to be beautiful or just, we must also accept the "existence of separate essences for hair, mud, and dirt".

Older social theories were often conceptually essentialist. In biology and other natural sciences, essentialism provided the rationale for taxonomy at least until the time of Charles Darwin. The role and importance of essentialism in modern biology is still a matter of debate. Beliefs which posit that social identities such as race, ethnicity, nationality, or gender are essential characteristics have been central to many discriminatory or extremist ideologies. For instance, psychological essentialism is correlated with racial prejudice. Essentialist views about race have also been shown to diminish empathy when dealing with members of another racial group. In medical sciences, essentialism can lead to a reified view of identities, leading to fallacious conclusions and potentially unequal treatment.

The Seventh Letter of Plato is an epistle that tradition has ascribed to Plato. It is by far the longest of the epistles of Plato and gives an autobiographical account of his activities in Sicily as part of the intrigues between Dion and Dionysius of Syracuse for the tyranny of Syracuse. It also contains an extended philosophical interlude concerning the possibility of writing true philosophical works and the theory of forms. Assuming that the letter is authentic, it was written after Dion was assassinated by Calippus in 353 BC and before the latter was in turn overthrown a year later.