9 ideas
| 2945 | Most philosophers start with reality and then examine knowledge; Descartes put the study of knowledge first [Lehrer] |
| Full Idea: Some philosophers (e.g Plato) begin with an account of reality, and then appended an account of how we can know it, ..but Descartes turned the tables, insisting that we must first decide what we can know. | |
| From: Keith Lehrer (Theory of Knowledge (2nd edn) [2000], I p.2) |
| 2946 | You cannot demand an analysis of a concept without knowing the purpose of the analysis [Lehrer] |
| Full Idea: An analysis is always relative to some objective. It makes no sense to simply demand an analysis of goodness, knowledge, beauty or truth, without some indication of the purpose of the analysis. | |
| From: Keith Lehrer (Theory of Knowledge (2nd edn) [2000], I p.7) | |
| A reaction: Your dismantling of a car will go better if you know what a car is for, but you can still take it apart in ignorance. |
| 3653 | My Meditations are the complete foundation of my physics [Descartes] |
| Full Idea: My six Meditations contain all the foundations of my physics, …and their principles destroy those of Aristotle. | |
| From: René Descartes (Letters to Mersenne [1640], 1641.01.28) |
| 4736 | Truth is such a transcendentally clear notion that it cannot be further defined [Descartes] |
| Full Idea: Truth is such a transcendentally clear notion that it cannot be further defined. | |
| From: René Descartes (Letters to Mersenne [1640], 1642), quoted by Pascal Engel - Truth Intro | |
| A reaction: This is the view endorsed by Davidson. It is tempting to take basic concepts as axiomatic, but philosophers can't make that move every time they are in trouble. I have to say, though, that truth is a good candidate. |
| 14633 | How do we tell a table's being contingently plastic from its being essentially plastic? [Jackson] |
| Full Idea: On a friendly reading of Quine, there is nothing to make the difference between a table's being contingently plastic and its being essentially plastic. | |
| From: Frank Jackson (Possible Worlds and Necessary A Posteriori [2010], 5) | |
| A reaction: This is, of course, the dreaded modern usage of 'essential' to just mean 'necessary' and nothing more. In my view, there may be a big problem with knowing whether a problem is necessary, but knowing whether it is essential is much easier. |
| 14635 | An x is essentially F if it is F in every possible world in which it appears [Jackson] |
| Full Idea: On the possible world's account, x's being essentially F is nothing more nor less than x's being F in every world in which it appears. | |
| From: Frank Jackson (Possible Worlds and Necessary A Posteriori [2010], 6) | |
| A reaction: There you go - 'true in every possible world' is the definition of metaphysical necessity, not the definition of essence. Either get back to Aristotle, or stop (forever!) talking about 'essence'! |
| 14632 | Quine may have conflated de re and de dicto essentialism, but there is a real epistemological problem [Jackson] |
| Full Idea: The unfriendly response to Quine's objection to essentialism is that it conflates the de re and the de dicto. The friendly response is that behind that conflation is a real epistemological problem for essentialism. | |
| From: Frank Jackson (Possible Worlds and Necessary A Posteriori [2010], 1) | |
| A reaction: He cites Richard Cartwright 1968 for the friendly response. The epistemological question is how we can know the essentialness of an essence. |
| 14631 | How can you show the necessity of an a posteriori necessity, if it might turn out to be false? [Jackson] |
| Full Idea: If something is offered as a candidate necessary a posteriori truth, how could we show that it is necessary, in the face of the fact that it takes investigation to show that it is true, and so, in some sense, it might have turned out to be false? | |
| From: Frank Jackson (Possible Worlds and Necessary A Posteriori [2010], 1) | |
| A reaction: This is the topic of his paper, which he compares with how we can know that essences are essential. |
| 3652 | I can't prove the soul is indestructible, only that it is separate from the mortal body [Descartes] |
| Full Idea: I don't know how to demonstrate that God cannot annihilate the soul, but only that it is entirely distinct from the body, and consequently that it is not naturally subject to die with it, which is all that is required to establish religion. | |
| From: René Descartes (Letters to Mersenne [1640], 1640.02.24) |