Philosophical Concepts: From Aristotle to Plato
Hylomorphism: Aristotle
Aristotle’s ontological study (study of being) in his Metaphysics defines substance as something that has an entity in itself and needs no other to exist. He distinguishes between primary substance (concrete beings) and secondary substance (universal forms). Aristotle’s hylomorphic theory posits that primary substance is composed of matter and form. Matter is the unknown, basic substrate of material things, capable of plurality. Form, which determines matter, is the essence of things, common to all species. Both components are inseparable, with form having priority, making beings intelligible.
Cartesian Doubt
Descartes’s doubt is a radical critique of all knowledge, provisionally considered false if doubt exists. This methodical doubt questions everything to arrive at indubitable truth. It is a universal doubt, applicable to all beliefs, even the most obvious. Radical doubt extends to mathematics and science, with Descartes illustrating the idea of an evil genius deceiving the subject. Descartes finds one self-evident truth: the act of thinking itself. Thus, he arrives at his principle, cogito, ergo sum (I think, therefore I am).
Process of Knowledge: Kantian Philosophy
For Kant, knowledge is expressed through judgments, particularly synthetic a priori judgments used by science. Kant distinguishes judgments based on the relationship between subject and predicate. Analytic judgments don’t increase knowledge as the predicate is included in the subject. Synthetic judgments add information, the predicate not being included in the subject. Kant further divides synthetic judgments into a posteriori (based on experience, not universal or necessary) and a priori (universal and necessary, independent of experience). He identifies synthetic a priori judgments as the basis for scientific knowledge.
Paths to A Priori Knowledge
The foundation of knowledge begins with sensibility. Kant studies space and time as a priori forms of sensibility, the ways we perceive sensory impressions. Space and time are pure intuitions, filled with external impressions. Structured perceptions become phenomena, unified in understanding, the second form of a priori knowledge. Understanding judges phenomena, organizing them into categories of quantity, quality, and modality. Sensibility and understanding are related, both necessary for knowledge. Reason then universalizes and unifies knowledge through World (external experience), Soul (inner experience), and God (the connection between them). Kant considers these ideas as regulators of reason, beyond experience, studied not by physics but by a phenomenal science.
Nature for the Pre-Socratics
The Pre-Socratics introduced the study of physis (nature), referring to natural reality. Physis is the order of the universe, a cosmos where parts have an inner force to create, develop, and maintain order. They sought the arche, the principle or origin of all things. Some identified the arche as a single substance (water for Thales, air for Anaximenes), while others proposed multiple substances. They viewed truth as aletheia (unveiling) and replaced mythical thought with rational thought, the logos.
Heraclitus and Parmenides
Heraclitus and Parmenides, Pre-Socratic philosophers, focused on physis through rational discourse, conceiving truth as aletheia (discovery) and seeking the arche. Heraclitus described nature as mobile and dynamic, based on observation and experience, explaining reality as a structure of opposing forces. He posited the logos (universal law) as governing nature, with fire as the arche, consuming and creating. Parmenides discovered the arche through the path of truth, revealing being as eternal, unique, indivisible, immutable, and limited. He argued that anything lacking these features would be non-being, which does not exist. Parmenides also distinguished between reason and opinion; reason reveals true being, while the senses provide mere opinion (doxa). Plato’s theory of Ideas partly builds on this distinction.
Theory of Ideas: Plato
Plato developed the theory of Ideas with ethical, political, and scientific intentions. Influenced by Heraclitus (the changing sensible world), the Pythagoreans (the immortal soul), and Socrates (the need for knowledge beyond the changing world), Plato sought to understand true reality. Ethically, Plato posited the existence of eternal and immutable moral ideas (e.g., knowing the good requires knowing the Idea of Good). Politically, he used dialectic to understand the order of Ideas and proposed philosopher-kings. Scientifically, he focused on the universal, stable, and permanent (Ideas). Plato argued that Ideas exist independently, with things in our minds being imperfect copies. This ontological and epistemological dualism distinguishes between the sensible world (things) and the intelligible world (Ideas). The sensible world is known through the senses and is changing, while the intelligible world is known through reason and comprises the true, unchanging reality. Ideas are unique, eternal, and unchanging, unlike the things that imitate them.