Ideas of Jean Buridan, by Theme

[French, 1298 - 1360, Probably born at Bethune, France.]

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2. Reason / A. Nature of Reason / 9. Limits of Reason
A rational donkey would starve to death between two totally identical piles of hay
     Full Idea: A rational donkey faced with two totally identical piles of hay would be unable to decide which one to eat first, and would therefore starve to death
     From: report of Jean Buridan (talk [1338]) by PG - Db (ideas)
     A reaction: also De Caelo 295b32 (Idea 19740).
9. Objects / C. Structure of Objects / 4. Quantity of an Object
Without magnitude a thing would retain its parts, but they would have no location
     Full Idea: If magnitude were removed from matter by divine power, it would still have parts distinct from one another, but they would not be positioned either outside one another or inside one another, because position would be removed.
     From: Jean Buridan (Questions on Aristotle's Physics [1346], I.8 f. 11va), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 14.4
     A reaction: This shows why Quantity is such an important category for scholastic philosopher.
9. Objects / E. Objects over Time / 8. Continuity of Rivers
A thing is (less properly) the same over time if each part is succeeded by another
     Full Idea: Less properly, one thing is said to be numerically the same as another according to the continuity of distinct parts, one in succession after another. In this way the Seine is said to be the same river after a thousand years.
     From: Jean Buridan (Questions on Aristotle's Physics [1346], I.10, f. 13vb), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 29.3
     A reaction: This is a rather good solution to the difficulty of the looser non-transitive notion of a thing being 'the same'. The Ship of Theseus endures (in the simple case) as long as you remember to replace each departing plank. Must some parts be originals?
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / b. Primary/secondary
Why can't we deduce secondary qualities from primary ones, if they cause them?
     Full Idea: The entire difficulty in this question is why through a knowledge of the primary tangible qualities we cannot come to a knowledge of flavors or odors, since these are their causes, since we often go from knowledge of causes to knowing their effects.
     From: Jean Buridan (Questions on Aristotle's Posterior Analytics [1344], I.28c), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 22.2
     A reaction: He is commenting on Idea 16725. Still a nice puzzle in the philosophy of mind. Will neuroscientists ever be able to infer to actual character of some quale, just from the structures of the neurons?
14. Science / A. Basis of Science / 2. Demonstration
Induction is not demonstration, because not all of the instances can be observed
     Full Idea: Inductions are not demonstrations, because they do not conclude on account of their form, since it is not possible to make an induction from all cases.
     From: Jean Buridan (Questions on Aristotle's Physics [1346], I.15 f. 18vb), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 02.3
     A reaction: Thus showing that demonstration really is meant to be as conclusive as a mathematical proof, and that Aristotle seems to think such a thing is possible in physical science.
14. Science / C. Induction / 2. Aims of Induction
Science is based on induction, for general truths about fire, rhubarb and magnets
     Full Idea: Induction should be regarded as a principle of natural science. For otherwise you could not prove that every fire is hot, that all rhubarb is purgative of bile, that every magnet attracts iron.
     From: Jean Buridan (Questions on Aristotle's Physics [1346], I.15 f. 18vb), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 02.3
     A reaction: He is basing this on Aristotle, and refers to 'Physics' 190a33-b11.