Knowledge – Protagoras, Socrates, Plato, Descartes, Leibniz, Bacon, Locke YouTube Lecture Handouts Part 2

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What is Knowledge? Protagoras, Socrates, Plato, Descartes, Leibniz, Bacon, Locke | Philosophy | NET

Descartes

Descartes Knowledge is Analytic

Knowledge is Analytic

Comes from pure thought

Clearness & Distinction

  • Descartes was a Rationalist, and, according to him, there are some ideas in the mind of man which do not come from the sense. These ideas are present in every mind from the very birth and are self-evident.
  • All knowledge come from pure thought as a logical deduction from these self-evident innate ideas, in complete independence of the senses. Knowledge is always analytic.
  • An analytic proposition is one in which the predicate simply analyses the subject, whereas a synthetic proposition is that in which the predicate adds something new to the subject.
  • “All red flowers are red” is an analytic proposition, whereas “all red flowers have five petals” , is a synthetic proposition. Analytic propositions are a priori, and, therefore, necessarily true — its denial leads us to self-contradiction. Its truth is self-evident.
  • Descartes had divided ideas into three classes: adventitious, fictitious, and innate ideas, and held that it is these innate ideas that give us philosophical knowledge. But, according to Locke, there is no idea in the understanding from birth, and all our knowledge comes from adventitious ideals or ideas of sensation.
  • The term ‘clear and distinct idea’ was used by Descartes in his ‘Meditations on First Philosophy’ , the book in which he comes up with the famous phrase ‘I think, therefore I am’ .
  • In the ‘Meditations’ Descartes is in search of certainty and, in order to find things that he is certain of, he has decided, quite sensibly, to get rid of all of the things that he is uncertain of and the things that he՚s left with when he՚s done all of that are going to be the certain ones

Kant: Knowledge is Synthetic a Priori

  • Synthetic a priori proposition, in logic, a proposition the predicate of which is not logically or analytically contained in the subject i.e.. , synthetic and the truth of which is verifiable independently of experience i.e.. , a priori. Thus, the proposition ‘Some bodies are heavy’ is synthetic because the idea of heaviness is not necessarily contained in that of bodies.
  • Synthetic a priori knowledge is central to the thought of Immanuel Kant, who argued that some such a priori concepts are presupposed by the very possibility of experience.
  • Immanuel Kant՚s Critique of Pure Reason (1781) is an investigation into the origin of human knowledge, and it is an examination of the relation between a priori knowledge and a posteriori knowledge.

Leibniz

Leibniz Human under ¬Standing
  • New Essays on Human Understanding
  • Time sensations come first but are confused perceptions
  • Experiences are entirely internal, it is yet objectively real as representation of universe in accordance to pre-established harmony a priori and posteriori, innate and experiential
  • As a monad, the soul of man is not, as in Locke՚s view, purely passive ‘tabula rasa’ , continually receiving external impressions. It is an active force and is the spontaneous source of all its ideas. All its ideas are, therefore, innate. But all the ideas are not clear and distinct from the beginning. The universal truths do not exist already and consciously in the mind at the time of birth.
  • Here Leibniz agrees with Locke in holding that in point of time sensations come first, though these sensations, according to Leibniz, are only confused perceptions or indistinct representations of things external to the individual mind.
  • Universal knowledge is implicitly involved in the sensations themselves, although they are brought to consciousness by the gradual process of clearing up of the original confused sense experiences.
  • The self-evidence of universal and necessary truths is the result of experience, though that experience is purely internal. And, though all our ideas are innate, there are many which can never rise to the perfect clearness and distinctions of self-evident truths (as by Descartes) , but which we have quite a sufficient ground for recognising as true.
  • Further, though our experiences are entirely internal, it is yet objectively real, for it consists in a representation of the whole universe, in accordance with the Pre-established harmony between substances. Human knowledge is thus, at once, a priori and posteriori, innate and experiential.
  • A priori knowledge is that which is independent from experience. Examples include mathematics, tautologies, and deduction from pure reason. A posteriori knowledge is that which depends on empirical evidence. Examples include most fields of science and aspects of personal knowledge.

Mind is like a Monad (indivisible unit or atom)

Truths of Reason - law of Contradiction and the law of Identity

Truths of matters of fact

  • Leibniz՚s theory of knowledge follows logically from his metaphysics. In metaphysics, Leibniz showed that as a monad our mind is like a universe in miniature. It is self-active, conscious atom which reflects the whole universe within itself.
  • Monads are windowless, so that nothing can act on them from outside. Like a living mirror it generates its ideas from within itself. From this nature of the monad, it follows that all its ideas are innate; and all propositions (knowledge) are a priori: universal and necessary. Leibniz distinguishes between Truths of Reason, and Truths of matters of fact.
  • Truths of Reason depend on two fundamental laws of thought viz. , the law of Contradiction and the law of Identity. All truths of Reason are self-evident and, therefore, necessarily true. Denial of truths of reason leads us to self-contradiction. The proposition “Red flowers are red” is a truth of reason. If we say “Red flowers are not red” , we are involved in self-contradiction which is necessarily false.
  • Propositions relating to matters of fact are not necessary, but contingent. The truth or falsity of such propositions depends entirely on the correspondence with facts. This correspondence is known by experience. The truth of such propositions is posteriori or derived from sense-experience. “Alexander was the pupil of Aristotle” .
  • This proposition is a proposition relating to matter of fact, the denial of which does not result in self-contradiction. The proposition may be false, if it does not correspond to matter-of-fact reality. It is posteriori, contingent and relative.
  • Propositions may also be analytic or synthetic. An analytic proposition is one in which the predicate simply analyses the subject, whereas a synthetic proposition is that in which the predicate adds something new to the subject.
  • “All red flowers are red” is an analytic proposition, whereas “all red flowers have five petals” , is a synthetic proposition. Analytic propositions are a priori, and, therefore, necessarily true — its denial leads us to self-contradiction. Its truth is self-evident.
  • All true propositions are analytic for Leibniz. The predicate of an analytic proposition is contained in the subject. All analytic propositions are, thus, self-evident.

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