Combining Texts

All the ideas for 'works', 'A priori/A posteriori' and 'Reply to Fifth Objections'

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7 ideas

5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction

10121	Contradiction is not a sign of falsity, nor lack of contradiction a sign of truth [Pascal]
	Full Idea: Contradiction is not a sign of falsity, nor the lack of contradiction a sign of truth.
	From: Blaise Pascal (works [1660]), quoted by A.George / D.J.Velleman - Philosophies of Mathematics Ch.6
	A reaction: [Quoted in Auden and Kronenberger's Book of Aphorisms] Presumably we would now say that contradiction is a purely formal, syntactic notion, and not a semantic one. If you hit a contradiction, something has certainly gone wrong.

9. Objects / B. Unity of Objects / 2. Substance / a. Substance

3626	Knowing the attributes is enough to reveal a substance [Descartes]
	Full Idea: I have never thought that anything more is required to reveal a substance than its various attributes.
	From: René Descartes (Reply to Fifth Objections [1641], 360)

12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / a. Innate knowledge

3630	Our thinking about external things doesn't disprove the existence of innate ideas [Descartes]
	Full Idea: You can't prove that Praxiteles never made any statues on the grounds that he did not get from within himself the marble from which he sculpted them.
	From: René Descartes (Reply to Fifth Objections [1641], 362)

12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective

3913	Maybe imagination is the source of a priori justification [Casullo]
	Full Idea: Some maintain that experiments in imagination are the source of a priori justification.
	From: Albert Casullo (A priori/A posteriori [1992], p.1)
	A reaction: What else could assessments of possibility and necessity be based on except imagination?

18. Thought / D. Concepts / 2. Origin of Concepts / c. Nativist concepts

3631	A blind man may still contain the idea of colour [Descartes]
	Full Idea: How do you know that there is no idea of colour in a man born blind?
	From: René Descartes (Reply to Fifth Objections [1641], 363)

28. God / B. Proving God / 2. Proofs of Reason / a. Ontological Proof

3640	Possible existence is a perfection in the idea of a triangle [Descartes]
	Full Idea: Possible existence is a perfection in the idea of a triangle, just as necessary existence is a perfection in the idea of God.
	From: René Descartes (Reply to Fifth Objections [1641], 383)

3639	Necessary existence is a property which is uniquely part of God's essence [Descartes]
	Full Idea: In the case of God necessary existence is in fact a property in the strictest sense of the term, since it applies to him alone and forms a part of his essence as it does of no other thing
	From: René Descartes (Reply to Fifth Objections [1641], 383)