display all the ideas for this combination of texts
4 ideas
| 12611 | Necessity makes alternatives impossible [Aristotle] |
| Full Idea: Necessity is what makes it impossible for something to be other than it is. | |
| From: Aristotle (Metaphysics [c.324 BCE], 1015b03) | |
| A reaction: Note that necessity here seems like an active force, rather than a mere description of a logical or metaphysical state of affairs. The underlying idea seems to be that essences enforce necessities, but it doesn't say that here. |
| 17852 | A thing has a feature necessarily if its denial brings a contradiction [Aristotle] |
| Full Idea: If anything has the property of being perishable it has it of necessity, on pain of one and the same thing being perishable and imperishable. | |
| From: Aristotle (Metaphysics [c.324 BCE], 1059a05) | |
| A reaction: Of course the perishable could become imperishable over time, without contradiction. This illustrates the foundational idea that a proposition is necessary if its negation is a contradiction. [...actually this argument is invalid as it stands!] |
| 17058 | What many people consider merely physically necessary I consider completely necessary [Kripke] |
| Full Idea: My third lecture suggests that a good deal of what contemporary philosophy regards as mere physical necessity is actually necessary tout court. | |
| From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], Add (g)) | |
| A reaction: He avoids the term 'metaphysically necessary', which most people would not use for this point. |
| 4970 | What is often held to be mere physical necessity is actually metaphysical necessity [Kripke] |
| Full Idea: My third lecture suggests that a good deal of what contemporary philosophy regards as mere physical necessity is actually necessary 'tout court'. | |
| From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], Add (g)) | |
| A reaction: This huge claim rides in on the back of Kripke's very useful clarifications. It is the 'new essentialism', and seems to me untenable in this form. There is no answer to Hume's request for evidence of necessity. Why can't essences (and laws) change? |