display all the ideas for this combination of texts
18 ideas
| 11283 | There is pure deductive reasoning, and explanatory demonstration reasoning [Aristotle, by Politis] |
| Full Idea: Aristotle distinguishes between deductive reasoning (sullogismos) and demonstration (apodeixis). All demonstration is deductive reasoning, but not all deductive reasoning is demonstration. | |
| From: report of Aristotle (Posterior Analytics [c.327 BCE], Bk I.2) by Vassilis Politis - Aristotle and the Metaphysics 5.3 | |
| A reaction: This sounds not far off the distinction between single-turnstile (formal proof) and double-turnstile (semantic consequence). Politis says, though, that the key point is the demonstration is explanatory. |
| 224 | When questions are doubtful we should concentrate not on objects but on ideas of the intellect [Plato] |
| Full Idea: Doubtful questions should not be discussed in terms of visible objects or in relation to them, but only with reference to ideas conceived by the intellect. | |
| From: Plato (Parmenides [c.364 BCE], 135e) |
| 22081 | Let thought follow its own course, and don't interfere [Hegel] |
| Full Idea: Let thought follow its own course; and I think badly whenever I add something of my own. | |
| From: Georg W.F.Hegel (Logic (Encyclopedia I) [1817], §24 Add 2), quoted by Stephen Houlgate - Hegel p.100 | |
| A reaction: The idea that reason has a course of its own is a mega-assumption, which I would only accept after a lot of persuasion, which I doubt that Hegel can provide. The modern analytic idea of metaphysics as logic has a similar basis. |
| 15626 | Categories create objective experience, but are too conditioned by things to actually grasp them [Hegel] |
| Full Idea: It is the categories that elevate mere perception into objectivity, into experience; but these concepts ...are conditioned by the given material. ...Hence the understanding, or cognition through categories, cannot become cognizant of things-in-themselves. | |
| From: Georg W.F.Hegel (Logic (Encyclopedia I) [1817], §43-4) | |
| A reaction: As one often fears with Hegel, this sounds like a deep insight, but is less persuasive when translated into simpler English (if I've got it right!). Being 'conditioned by the material' strikes me as just what is needed for good categories. |
| 1672 | Maybe everything could be demonstrated, if demonstration can be reciprocal or circular [Aristotle] |
| Full Idea: Some optimists think understanding arises only through demonstration, but say there could be demonstration of everything, for it is possible to demonstrate in a circle or reciprocally. | |
| From: Aristotle (Posterior Analytics [c.327 BCE], 72b16) | |
| A reaction: I'm an optimist in this sense, though what is being described would probably best be called 'large-scale coherence'. Two reciprocal arguments look bad, but a hundred look good. |
| 15616 | If truth is just non-contradiction, we must take care that our basic concepts aren't contradictory [Hegel] |
| Full Idea: If truth were nothing more than lack of contradiction, one would have to examine first of all, with regard to each concept, whether it does not on its own account, contain an inner contradiction. | |
| From: Georg W.F.Hegel (Logic (Encyclopedia I) [1817], §33 Rem) | |
| A reaction: This is a very nice thought, which modern analytic philosophers, steeped in logic, should think about. It is always presumed that a contradiction is between a proposition and its negation, not some inner feature. |
| 1684 | Two falsehoods can be contrary to one another [Aristotle] |
| Full Idea: There are falsehoods which are contrary to one another and cannot be the case together e.g. that a man is a horse or a cow. | |
| From: Aristotle (Posterior Analytics [c.327 BCE], 88a29) |
| 232 | Opposites are as unlike as possible [Plato] |
| Full Idea: Opposites are as unlike as possible. | |
| From: Plato (Parmenides [c.364 BCE], 159a) |
| 8937 | Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic [Hegel on Plato] |
| Full Idea: Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic. | |
| From: comment on Plato (Parmenides [c.364 BCE]) by Georg W.F.Hegel - Phenomenology of Spirit Pref 71 | |
| A reaction: It is a long way from the analytic tradition of philosophy to be singling out a classic text for its 'artistic' achievement. Eventually we may even look back on, say, Kripke's 'Naming and Necessity' and see it in that light. |
| 21767 | Dialectic is seen in popular proverbs like 'pride comes before a fall' [Hegel] |
| Full Idea: In the domain of individual ethics, we find the consciousness of dialectic in those universally familiar proverbs 'pride goes before a fall' and 'too much wit outwits itself'. ...Joy relieves itself in tears, and melancholy can be revealed in a smile. | |
| From: Georg W.F.Hegel (Logic (Encyclopedia I) [1817], §81), quoted by Stephen Houlgate - An Introduction to Hegel 02 'The Method' | |
| A reaction: 'Too clever by half' is the English version. Hegel's dialectic suggests that each concept somehow implies its opposite, rather than a mere mercurial drift from one extreme to the other. Most pride doesn't lead to a fall. |
| 15638 | Dialectic is the moving soul of scientific progression, the principle which binds science together [Hegel] |
| Full Idea: The dialectical constitutes the moving soul of scientific progression, and it is the principle through which alone immanent coherence and necessity enter into the content of science. ..[Add 1] It is the principle of all motion, of all life. | |
| From: Georg W.F.Hegel (Logic (Encyclopedia I) [1817], §81) |
| 15639 | Socratic dialectic is subjective, but Plato made it freely scientific and objective [Hegel] |
| Full Idea: It is in the Platonic philosophy that dialectic first occurs in a form which is freely scientific, and hence also objective. With Socrates, dialectical thinking still has a predominantly subjective shape, consistent with his irony. | |
| From: Georg W.F.Hegel (Logic (Encyclopedia I) [1817], §81 Add1) | |
| A reaction: I don't understand how dialectic can be 'objective', given that it is a method rather than a belief. Plato certainly seems to elevate dialectic into something almost mystical, because of what is said to be within its power. |
| 15615 | Older metaphysics became dogmatic, by assuming opposed assertions must be true and false [Hegel] |
| Full Idea: The older metaphysics became dogmatism because, given the nature of finite determinations, it had to assume that of two opposed assertions (of the kind that those propositions were) one must be true and the other false. | |
| From: Georg W.F.Hegel (Logic (Encyclopedia I) [1817], §32) | |
| A reaction: While dialethism in logic looks very dubious to me, I have every sympathy with Hegel when it comes to the reasonings of ordinary language. There it is much harder to know whether you are addressing truly opposed assertions. |
| 12145 | Definitions are of what something is, and that is universal [Aristotle] |
| Full Idea: Definitions are thought to be of what something is, and what something is is in every case universal and positive. | |
| From: Aristotle (Posterior Analytics [c.327 BCE], 90b05) | |
| A reaction: This is exhibit A for those who think that Aristotelian essences concern the genus, rather than the particular. I suspect that this idea is best expressed as 'all we can say by way of definition of a particular thing involves the use of universals'. |
| 12075 | An Aristotelian definition is causal [Aristotle, by Witt] |
| Full Idea: An Aristotelian definition is causal. | |
| From: report of Aristotle (Posterior Analytics [c.327 BCE], Bk II.2) by Charlotte Witt - Substance and Essence in Aristotle 1.5 | |
| A reaction: [She refers us to Posterior Analytics II.2] This is important if we are tempted to follow a modern line of saying that we want Aristotelian essences, and that these are definitions. We ain't thinking of dictionaries. |
| 12384 | Definition by division needs predicates, which are well ordered and thorough [Aristotle] |
| Full Idea: To establish a definition through division, you must aim for three things: you must take what is predicated in what the thing is; you must order these items as first or second; and you must ensure that these are all there are. | |
| From: Aristotle (Posterior Analytics [c.327 BCE], 97a23) | |
| A reaction: This gives an indication of the thoroughness that Aristotle expects from a definition. They aren't like dictionary definitions of words. He expects definitions to often be very lengthy (see Idea 12292). |
| 9066 | You can define objects by progressively identifying what is the same and what is different [Aristotle] |
| Full Idea: Find what is in common among items similar and undifferentiated, then do the same for items of the same kind as the first group but a different form, and so on, till you come to a single account: this will be the definition of the object. | |
| From: Aristotle (Posterior Analytics [c.327 BCE], 97b07-14) | |
| A reaction: [His example is distinguishing 'magnanimity' from 'indifference to fortune' among people] Presumably this process works for the formation of new concepts (e.g. in biology), as well as for the definition of familiars in terms of other familiars. |
| 12382 | What it is and why it is are the same; screening defines and explains an eclipse [Aristotle] |
| Full Idea: What it is and why it is are the same. What is an eclipse? Privation of light from the moon by screening of the earth. Why is there an eclipse? ...What is a harmony? A numerical ratio between high and low. Why do the high and low harmonize? The ratio. | |
| From: Aristotle (Posterior Analytics [c.327 BCE], 90a15) | |
| A reaction: This is right at the heart of Aristotelian essentialism, and (I take it) modern scientific essentialism. If you fully know what cigarette tars are, and what human cell structure is, you understand immediately why cigarettes cause cancer. |