7 ideas
7726 | Aristotelian logic dealt with inferences about concepts, and there were also proposition inferences [Weiner] |
Full Idea: Till the nineteenth century, it was a common view that Aristotelian logic could evaluate inferences whose validity was based on relations between concepts, while propositional logic could evaluate inferences based on relations between propositions. | |
From: Joan Weiner (Frege [1999], Ch.3) | |
A reaction: Venn diagrams relate closely to Aristotelian syllogisms, as each concept is represented by a circle, and shows relations between sets. Arrows seem needed to represent how to go from one proposition to another. Is one static, the other dynamic? |
16978 | If conceivability is a priori coherence, that implies possibility [Tahko] |
Full Idea: Maybe conceivability could be understood as a priori coherence, which implies possibility. | |
From: Tuomas E. Tahko (The Epistemology of Essence (draft) [2013], 3.2) | |
A reaction: I'm not quite sure why 'a priori' has to be there. Assessing conceivability just is assessing coherence. That couches it as a rational activity, rather than as a purely imaginary one. Trying to conceive a square circle isn't just daydreaming. |
16975 | Essences are used to explain natural kinds, modality, and causal powers [Tahko] |
Full Idea: Essences are supposed to do a lot of explanatory work: natural kinds can be identified in terms of their essences, metaphysical modality can be reduced to essence, the causal power of objects can be explained with the help of essence. | |
From: Tuomas E. Tahko (The Epistemology of Essence (draft) [2013], 1) | |
A reaction: Natural kinds and modality are OK with me, but I'm dubious about the third one. If an essence explains something's causal powers, I have no idea what an essence might be. Essence are largely characterised in terms of causal powers. |
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. |
16976 | Scientific essentialists tend to characterise essence in terms of modality (not vice versa) [Tahko] |
Full Idea: The conception of essence taken for granted in much of the 'scientific essentialist' literature is that essence can be explained in terms of modality (rather than the other way round). | |
From: Tuomas E. Tahko (The Epistemology of Essence (draft) [2013], 2.1) | |
A reaction: [He cites Ellis and Bird] That is, presumably, that they are inclined to say that the essence of gold is a set of necessary properties. Maybe conceptual necessities dictate the properties of gold, and they in turn dictate metaphysical necessities? |
16977 | If essence is modal and laws are necessary, essentialist knowledge is found by scientists [Tahko] |
Full Idea: If essence is conceived in terms of modality and the laws of nature are metaphysically necessary, it seems that the laws of nature constitute essentialist knowledge, so the discovery of essences is mostly due to scientists. | |
From: Tuomas E. Tahko (The Epistemology of Essence (draft) [2013], 2.1) | |
A reaction: This seems muddled to me. The idea that the laws themselves are essences is way off target. No one thinks all knowledge of necessities is essentialist. Mumford, for example, doesn't even believe in laws. |
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. |