Ideas from 'works' by René Descartes [1643], by Theme Structure

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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
Descartes showed a one-one order-preserving match between points on a line and the real numbers
                        Full Idea: Descartes founded analytic geometry on the assumption that there is a one-one order-preserving correspondence between the points on a line and the real numbers.
                        From: report of René Descartes (works [1643]) by William D. Hart - The Evolution of Logic 1
9. Objects / B. Unity of Objects / 2. Substance / e. Substance critique
Descartes thinks distinguishing substances from aggregates is pointless
                        Full Idea: Descartes thinks it is a pointless relic of scholastic metaphysics to dispute over the boundaries between substances and mere aggregates.
                        From: report of René Descartes (works [1643]) by Robert Pasnau - Metaphysical Themes 1274-1671 25.6
                        A reaction: This is Pasnau's carefully considered conclusion, with which others may not agree. It presumably captures the attitude of modern science generally to such issues.
12. Knowledge Sources / B. Perception / 3. Representation
Descartes said images can refer to objects without resembling them (as words do)
                        Full Idea: Descartes argued (in 'The World') that just as words refer to objects, but they do not resemble them, in the same way, visual images or other sensory inputs relate to objects without depicting them.
                        From: report of René Descartes (works [1643]) by Richard Tuck - Hobbes
                        A reaction: This strikes me as a rather significant and plausible claim, which might contain the germ of the idea of a language of thought. It is also the basis for the recent view that language is the best route to understanding the mind.
16. Persons / F. Free Will / 4. For Free Will
We have inner awareness of our freedom
                        Full Idea: We have inner awareness of our freedom.
                        From: René Descartes (works [1643])
                        A reaction: This begs a few questions. I may be directly aware that I have not been hypnotised, but no one would accept it as proof.
17. Mind and Body / A. Mind-Body Dualism / 2. Interactionism
Descartes discussed the interaction problem, and compared it with gravity
                        Full Idea: Descartes himself was well aware of the interaction problem, and corresponded uncomfortably with Princess Elizabeth on the matter; …he pointed out that gravity is causal despite not being a physical object.
                        From: report of René Descartes (works [1643]) by William Lycan - Consciousness n1.3
                        A reaction: Lycan observes that at least gravity is in space-time, unlike the Cartesian mind. Pierre Gassendi had pointed out the problem to Descartes in the Fifth Objection to the 'Meditations' (see Idea 3400).
26. Natural Theory / A. Speculations on Nature / 1. Nature
Nature is devoid of thought
                        Full Idea: It is Descartes who ratifies the idea that nature is devoid of thought.
                        From: report of René Descartes (works [1643]) by Quentin Meillassoux - After Finitude; the necessity of contingency 5
                        A reaction: His dualism is crucial, along with his ontological argument, because they make all mentality supernatural. Remember, for Descartes animals are mindless machines.
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / c. Matter as extension
Matter can't just be Descartes's geometry, because a filler of the spaces is needed
                        Full Idea: Notoriously, the Cartesian idea that matter is purely geometrical will not do, for it leaves no distinction between matter and empty volumes: a filler for these volumes is required.
                        From: comment on René Descartes (works [1643]) by Howard Robinson - Perception IX.3
                        A reaction: Descartes thinks of matter as 'extension'. Descartes's error seems so obvious that it is a puzzle why he made it. He may have confused epistemology and ontology - all we can know of matter is its extension in space.