Classical Western Epistemology and Metaphysics
What it is
Unit 2 follows Western answers to what is real and how we know it: the Pre-Socratic search for a first principle, Plato and Aristotle, medieval faith and reason, and the modern contest of rationalists (Descartes, Spinoza, Leibniz) and empiricists (Locke, Berkeley, Hume) that Kant tries to settle and Hegel turns into absolute idealism. NET tests attributions and the shape of the classic arguments.
Core concepts
Pre-Socratics, Sophists and Socrates. The Milesian Ionians sought the arche: Thales water, Anaximander the boundless (apeiron), Anaximenes air, changing by condensation and rarefaction. Heraclitus taught flux, fire and a logos uniting opposites; Parmenides, that Being is one and changeless, change being opinion. Pythagoras made number the principle; Anaxagoras, seeds set moving by Nous (mind); Democritus, with Leucippus, reduced all to atoms and void. The paid Sophists leaned to relativism (Protagoras: man is the measure of all things) and scepticism (Gorgias). Socrates sought universal definitions by elenchus (cross-examination), irony and maieutic "midwifery", holding virtue to be knowledge.
Plato. Knowledge (episteme) is of the unchanging Forms, opinion (doxa) of the sensible world. The Divided Line puts eikasia (images) and pistis (belief) under opinion, dianoia (mathematical thought) and noesis (intellection) under knowledge. The Ideas are eternal, perfect universals in which particulars participate, crowned by the Form of the Good (the Sun, the Cave). Learning is recollection (anamnesis; the Meno's slave boy). Dialectic climbs from hypotheses to an unhypothetical first principle (later, collection and division). The soul is immortal and tripartite (reason, spirit, appetite); God is the Demiurge of the Timaeus, shaping the world after the Forms.
Aristotle. The sciences are theoretical (first philosophy, mathematics, physics), practical (ethics, politics) and productive (poetics, rhetoric). Logic is an organon (instrument). Plato's separate Forms duplicate things, cannot explain change and invite the "third man" regress. A substance is matter (hyle) with form (morphe); change actualises potentiality (dynamis) as actuality (energeia). The four causes are material, formal, efficient and final. The soul is the form, the first actuality, of a living body: nutritive, sensitive, rational. God is the unmoved mover, pure actuality, thought thinking itself, moving all as an object of desire.
Medieval philosophy. Augustine: evil is no substance but a privation of good (privatio boni), and moral evil comes from misused free will. Anselm (Proslogion): God is that than which nothing greater can be conceived; were God only in the mind, a greater being, real too, could be conceived, a contradiction; so God exists in reality. Gaunilo replied with the perfect island; Kant denied existence is a real predicate. Aquinas: faith and reason cannot conflict; reason proves God exists, revelation alone gives the Trinity. Essence (what a thing is) and existence (that it is) differ in creatures but are identical in God. The Five Ways argue from motion, efficient causation, contingency, degrees of perfection and governance.
Descartes. The method: accept only the clear and distinct, divide problems, go from simple to complex, enumerate fully; clarity and distinctness is the criterion of truth, guaranteed by a non-deceiving God. Methodological doubt (senses, dreaming, the evil demon) halts at cogito ergo sum. Ideas are innate, adventitious or factitious. Mind is thinking, unextended substance; matter, extended and unthinking. God is proved from the idea of the infinite, which only an infinite cause could produce, and ontologically: existence belongs to God's essence as its angle-sum belongs to a triangle. Mind and body interact through the pineal gland.
Spinoza. Substance is what is in itself and conceived through itself, so only one exists: God or Nature (Deus sive Natura), hence pantheism. Of its infinite attributes we know two, thought and extension; finite things are its modes. Parallelism: the order and connection of ideas is the same as that of things, so mind and body correspond without interacting. Knowing has three orders: imagination or opinion, reason (adequate ideas of common properties) and intuitive knowledge (scientia intuitiva), source of the intellectual love of God (amor Dei intellectualis).
Leibniz. Monads are simple, windowless substances with perception and appetition, each mirroring the universe. Truths of reason are necessary and rest on non-contradiction; truths of fact are contingent and rest on sufficient reason. By the identity of indiscernibles no two substances are exactly alike. Against Locke, ideas are virtually innate, like veins in marble. God is proved ontologically (once shown possible), from sufficient reason, from eternal truths and from pre-established harmony: God synchronised all monads, mind and body included, like clocks. Freedom: acts are certain, not necessary; reasons incline without necessitating.
Locke and Berkeley. Locke refutes innate ideas (no universal assent): the mind starts as white paper and gains simple and complex ideas from sensation and reflection. Substance is an unknown substratum. Primary qualities (solidity, extension, figure, motion, number) resemble our ideas; secondary ones (colour, sound, taste) are powers to cause ideas resembling nothing in the object. Knowledge perceives agreement or disagreement of ideas, in three grades: intuitive (one's own existence), demonstrative (God's) and sensitive (external things). Berkeley rejects the primary–secondary distinction and abstract ideas: esse est percipi. Solipsism is avoided because involuntary ideas of sense come from God, who perceives all; selves are spirits known by notion.
Hume. Every idea copies an impression. Knowledge concerns relations of ideas (certain, a priori, as in mathematics) or matters of fact (contingent, from experience): "Hume's fork". There is no impression of necessary connection: causality is constant conjunction plus custom, and induction has no non-circular justification. Belief in an external world is imagination's work; the self is a bundle of perceptions, personal identity a fiction. Metaphysics lacking both demonstration and experiment goes to the flames. He ends in mitigated scepticism, reason the slave of the passions.
Kant. The critical philosophy's Copernican revolution: objects conform to our cognition. Space and time are a priori forms of sensibility; twelve categories (quantity, quality, relation, modality) are pure concepts of understanding. The metaphysical deduction derives them from the forms of judgement; the transcendental deduction proves their objective validity through the unity of apperception. We know phenomena only; the noumenon is unknowable. The Ideas of Reason (soul, world as a whole, God) are only regulative; treated as known, they breed paralogisms, antinomies and failed proofs, so speculative metaphysics is rejected.
Hegel. Reality is Geist (Spirit) coming to know itself: absolute idealism, in which the rational is actual and the actual rational. The dialectical method advances through contradiction and Aufhebung (sublation, which cancels, preserves and raises); "thesis–antithesis–synthesis" is a label Hegel rarely used. The Logic opens with Being, which as wholly indeterminate is the same as Nothing; their truth is Becoming. Spirit is subjective, objective and absolute (art, religion, philosophy), and history is the progress of the consciousness of freedom.
Worked example
Classifying judgements. Step 1: is the predicate contained in the subject (analytic) or added (synthetic)? Step 2: is it known independently of experience (a priori)? Step 3: map to Hume and Leibniz.
| Judgement | Step 1 | Step 2 | Kant's class | Hume / Leibniz |
|---|---|---|---|---|
| All bodies are extended | Analytic | A priori | Analytic a priori | Relation of ideas / truth of reason |
| All bodies are heavy | Synthetic | A posteriori | Synthetic a posteriori | Matter of fact / truth of fact |
| 7 + 5 = 12 | Synthetic: 12 is not in "7 + 5" | A priori: necessary, universal | Synthetic a priori | Relation of ideas / truth of reason |
| Every event has a cause | Synthetic | A priori, as a category | Synthetic a priori | Hume: custom, not reason |
Result: analytic a posteriori stays empty. Synthetic a priori judgements are possible through the forms of sensibility (mathematics) and the categories (natural science).
Common traps
- Locke's grades: self intuitive, God demonstrative, external things sensitive; self and God get swapped.
- Mind–body: Descartes holds interaction, Spinoza parallelism (one substance), Leibniz pre-established harmony (many monads).
- Truths of reason rest on non-contradiction, truths of fact on sufficient reason, not the reverse.
- The metaphysical deduction asks where the categories come from; the transcendental deduction asks by what right they apply to objects.
Speed technique
- Arche ladder: Thales water, Anaximander apeiron, Anaximenes air, Heraclitus fire, Pythagoras number, Democritus atoms.
- Sort God-proofs: a priori from the concept (Anselm, Descartes's ontological) or a posteriori from effects (Aquinas).
- Kant's categories are 4 heads × 3 = 12; the Ideas of Reason are 3.
Check yourself
- Which Milesian made air the arche?
Show answer
Anaximenes — after Thales and Anaximander. - What does Plato compare to the Sun?
Show answer
The Form of the Good — it makes Forms knowable as the Sun makes things visible. - For Aquinas, how are essence and existence related in God?
Show answer
They are identical — in creatures they differ. - For Locke, how do we know God exists?
Show answer
Demonstratively — the self is known intuitively. - How does Kant classify 7 + 5 = 12?
Show answer
Synthetic a priori — 12 is not in "7 + 5", yet it is necessary.
Try it: Classical Western Epistemology and Metaphysics questions
Real questions from the NET Philosophy bank on exactly this skill. Pick an answer to see the full solution — the intuition, the worked steps, the faster methods and the traps.
According to Locke, our knowledge of the existence of God is:
Show the answer and worked solution
Answer: option B
Locke ranks knowledge in three degrees: intuitive, as of one's own existence; demonstrative, reached through a chain of intuitive steps; and sensitive, as of particular external things.
He argues that from one's own existence, and the principle that nothing cannot produce a being, it follows that an eternal, most powerful and knowing being exists.
So for Locke knowledge of God's existence is demonstrative, option B.
In Aristotle's account of a bronze statue, the end for which the statue is made, such as honouring a god, is its:
Show the answer and worked solution
Answer: option C
Aristotle names four causes: the material (the bronze), the formal (the shape or essence), the efficient (the sculptor's work that brings it about) and the final (the end for which it is made).
The purpose a thing serves is its 'that for the sake of which', the final cause or telos.
So the end for which the statue is made is its final cause, option C.
Kant classifies the arithmetical judgement '7 + 5 = 12' as:
Show the answer and worked solution
Answer: option D
The concept of the sum of 7 and 5 contains only the uniting of two numbers, not the concept 12, so the judgement adds something and is synthetic.
It is also necessary and universal, so it is known independently of experience and is a priori; Kant explains such mathematical judgements through the a priori forms of sensibility.
So '7 + 5 = 12' is synthetic a priori, option D.
In the Critique of Pure Reason, the argument that the categories are objectively valid because they are conditions of the synthetic unity of apperception, without which no experience of objects is possible, is the:
Show the answer and worked solution
Answer: option B
The metaphysical deduction shows where the categories come from: they are derived from the logical forms of judgement.
The transcendental deduction shows by what right they apply to objects, arguing that the unity of apperception requires them for any experience at all; the aesthetic treats space and time and the dialectic exposes the illusions of reason.
So the argument from the unity of apperception is the transcendental deduction, option B.
Match the thinkers in List – I with their doctrines in List – II and choose the correct answer from the options. List – I (Thinker) | List – II (Doctrine) --- | --- (a) Plato | (i) God is the unmoved mover, thought thinking itself (b) Aristotle | (ii) Learning is recollection (anamnesis) (c) Augustine | (iii) Essence and existence are identical in God alone (d) Aquinas | (iv) Evil is a privation of good, not a substance
Show the answer and worked solution
Answer: option C
Plato holds that learning is recollection of Forms the soul knew before birth (a – ii), and Aristotle's God is the unmoved mover, pure actuality, thought thinking itself (b – i).
Augustine answers the problem of evil by calling evil a privation of good, not a substance (c – iv), and Aquinas holds that essence and existence differ in creatures but are identical in God (d – iii).
So matching List I, from "Plato", gives a – ii, b – i, c – iv, d – iii, option C.
Answer above — every one shows its working.