10 ideas
| 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'! |
| 12177 | Human artefacts may have essences, in their purposes [Popper] |
| Full Idea: One might adopt the view that certain things of our own making, such as clocks, may well be said to have 'essences', viz. their 'purposes', and what makes them serve these purposes. | |
| From: Karl Popper (Conjectures and Refutations [1963], 3.3 n17) | |
| A reaction: This is from one of the arch-opponents of essentialism. Could we take him on a slippery slope into essences for evolved creatures, or their organs? His argument says admitting an essence for a clock prevents using it for another purpose. |
| 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. |
| 12176 | Science does not aim at ultimate explanations [Popper] |
| Full Idea: I contest the essentialist doctrine that science aims at ultimate explanations, one which cannot be further explained, and which is in no need of any further explanation. | |
| From: Karl Popper (Conjectures and Refutations [1963], 3.3) | |
| A reaction: If explanations are causal, this seems to a plea for an infinite regress of causes, which is an odd thing to espouse. Are the explanations verbal descriptions or things in the world. There can be no perfect descriptions, but there may be ultimate things. |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 12175 | Galilean science aimed at true essences, as the ultimate explanations [Popper] |
| Full Idea: The third of the Galilean doctrines of science is that the best, the truly scientific theories, describe the 'essences' or the 'essential natures' of things - the realities which lie behind the appearances. They are ultimate explanations. | |
| From: Karl Popper (Conjectures and Refutations [1963], 3.3) | |
| A reaction: This seems to be the seventeenth century doctrine which was undermined by Humeanism, and hence despised by Popper, but is now making a comeback, with a new account of essence and necessity. |
| 12179 | Essentialist views of science prevent further questions from being raised [Popper] |
| Full Idea: The essentialist view of Newton (due to Roger Cotes) ...prevented fruitful questions from being raised, such as, 'What is the cause of gravity?' or 'Can we deduce Newton's theory from a more general independent theory?' | |
| From: Karl Popper (Conjectures and Refutations [1963], 3.3) | |
| A reaction: This is Popper's main (and only) objection to essentialism - that it is committed to ultimate explanations, and smugly terminates science when it thinks it has found them. This does not strike me as a problem with scientific essentialism. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |