20 ideas
| 17596 | Coherence problems have positive and negative restraints; solutions maximise constraint satisfaction [Thagard] |
| Full Idea: A coherence problem is a set of elements connected by positive and negative restraints, and a solution consists of partitioning the elements into two sets (accepted and rejected) in a way that maximises satisfaction of the constraints. | |
| From: Paul Thagard (Coherence: The Price is Right [2012], p.42) | |
| A reaction: I'm enthusiastic about this, as it begins to clarify the central activity of epistemology, which is the quest for best explanations. |
| 17597 | Coherence is explanatory, deductive, conceptual, analogical, perceptual, and deliberative [Thagard] |
| Full Idea: I propose that there are six main kinds of coherence: explanatory, deductive, conceptual, analogical, perceptual, and deliberative. ...Epistemic coherence is a combination of the first five kinds, and ethics adds the sixth. | |
| From: Paul Thagard (Coherence: The Price is Right [2012], p.43) | |
| A reaction: Wonderful. Someone is getting to grips with the concept of coherence, instead of just whingeing about how vague it is. |
| 17598 | Explanatory coherence needs symmetry,explanation,analogy,data priority, contradiction,competition,acceptance [Thagard] |
| Full Idea: Informally, a theory of explanatory coherence has the principles of symmetry, explanation, analogy, data priority, contradiction, competition and acceptance. | |
| From: Paul Thagard (Coherence: The Price is Right [2012], p.44) | |
| A reaction: [Thagard give a concise summary of his theory here] Again Thagard makes a wonderful contribution in an area where most thinkers are pessimistic about making any progress. His principles are very plausible. |
| 19740 | A very hungry man cannot choose between equidistant piles of food [Aristotle] |
| Full Idea: The man who, though exceedingly hungry and thirsty, and both equally, yet being equidistant from food and drink, is therefore bound to stay where he is. | |
| From: Aristotle (On the Heavens [c.336 BCE], 296b33) | |
| A reaction: This is, of course, Buridan's famous Ass, but this quotation has the advantage of precedence, and also of being expressed in an original quotation (which does not exist for Buridan). |
| 17602 | Verisimilitude comes from including more phenomena, and revealing what underlies [Thagard] |
| Full Idea: A scientific theory is progressively approximating the truth if it increases its explanatory coherence by broadening to more phenomena and deepening by investigating layers of mechanisms. | |
| From: Paul Thagard (Coherence: The Price is Right [2012], p.46) |
| 17601 | Neither a priori rationalism nor sense data empiricism account for scientific knowledge [Thagard] |
| Full Idea: Both rationalists (who start with a priori truths and make deductions) and empiricists (starting with indubitable sense data and what follows) would guarantee truth, but neither even begins to account for scientific knowledge. | |
| From: Paul Thagard (Coherence: The Price is Right [2012], p.46) | |
| A reaction: Thagard's answer, and mine, is inference to the best explanation, but goes beyond both the a priori truths and the perceptions. |
| 17600 | Bayesian inference is forced to rely on approximations [Thagard] |
| Full Idea: It is well known that the general problem with Bayesian inference is that it is computationally intractable, so the algorithms used for computing posterior probabilities have to be approximations. | |
| From: Paul Thagard (Coherence: The Price is Right [2012], p.45) | |
| A reaction: Thagard makes this sound devastating, but then concedes that all theories have to rely on approximations, so I haven't quite grasped this idea. He gives references. |
| 17599 | The best theory has the highest subjective (Bayesian) probability? [Thagard] |
| Full Idea: On the Bayesian view, the best theory is the one with the highest subjective probability, given the evidence as calculated by Bayes's theorem. | |
| From: Paul Thagard (Coherence: The Price is Right [2012], p.45) |
| 398 | Each thing that has a function is for the sake of that function [Aristotle] |
| Full Idea: Each thing that has a function is for the sake of that function. | |
| From: Aristotle (On the Heavens [c.336 BCE], 286a08) | |
| A reaction: This is the central idea of Aristotle's Ethics. Did it originate with Plato, or Socrates, the young pupil Aristotle? I suspect the strong influence of Aristotle on later Plato. A major idea. Functions link the facts to life. |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom. | |
| From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88) | |
| A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate'). |
| 394 | An unworn sandal is in vain, but nothing in nature is in vain [Aristotle] |
| Full Idea: We say of a sandal which is not worn that it is in vain; God and nature, however, do nothing in vain. | |
| From: Aristotle (On the Heavens [c.336 BCE], 271a33) |
| 396 | There has to be some goal, and not just movement to infinity [Aristotle] |
| Full Idea: There has to be some goal, and not just movement to infinity. | |
| From: Aristotle (On the Heavens [c.336 BCE], 277a26) |
| 16102 | Aether moves in circles and is imperishable; the four elements perish, and move in straight lines [Aristotle, by Gill,ML] |
| Full Idea: For Aristotle, aether and the four sublunary elements obey different physical laws. Aether moves naturally in a circle and, unlike its lower counterparts, is not a source of perishability. The four sublunary elements move naturally in straight lines. | |
| From: report of Aristotle (On the Heavens [c.336 BCE]) by Mary Louise Gill - Aristotle on Substance Ch.2 | |
| A reaction: I think it is anachronistic for Gill to talk of 'obeying' and 'laws'. She should have said that they have different 'natures'. We can be amused by Greek errors, until we stare hard at the problems they were trying to solve. |
| 17463 | An element is what bodies are analysed into, and won't itself divide into something else [Aristotle] |
| Full Idea: An element is a body into which other bodies may be analyzed, present in them potentially or in actuality (which of these is still disputable), and not itself divisible into bodies different in form. That is what all men mean by element. | |
| From: Aristotle (On the Heavens [c.336 BCE], 302a05), quoted by Weisberg/Needham/Hendry - Philosophy of Chemistry 1.1 | |
| A reaction: This is the classic definition of an element, which endured for a long time, and has been replaced by an 'actual components' view. Obviously analysis nowadays goes well beyond the atoms. |
| 399 | If the more you raise some earth the faster it moves, why does the whole earth not move? [Aristotle] |
| Full Idea: If you raise some earth and release it, it moves and won't stay put, and the more you raise it the faster it moves, so why does the whole earth not move? | |
| From: Aristotle (On the Heavens [c.336 BCE], 294a12) |
| 20918 | Void is a kind of place, so it can't explain place [Aristotle] |
| Full Idea: It is absurd to explain place by the void, as though this latter were not itself some kind of place. | |
| From: Aristotle (On the Heavens [c.336 BCE], 309b24) | |
| A reaction: Presumably this is aimed at Democritus. |
| 402 | The Earth must be spherical, because it casts a convex shadow on the moon [Aristotle] |
| Full Idea: A lunar eclipse always has a convex dividing line, so, if it is eclipsed by the interposition of the earth, the circumference of the earth, being spherical, is responsible for the shape. | |
| From: Aristotle (On the Heavens [c.336 BCE], 297b29) |
| 403 | The earth must be round and of limited size, because moving north or south makes different stars visible [Aristotle] |
| Full Idea: Clearly the earth is round and not of great size, because when we move north or south we find that very different stars are visible. | |
| From: Aristotle (On the Heavens [c.336 BCE], 297b30) |
| 1498 | Everyone agrees that the world had a beginning, but thinkers disagree over whether it will end [Aristotle] |
| Full Idea: All thinkers agree that the world had a beginning, but some claim that, having come into existence, it is everlasting. | |
| From: Aristotle (On the Heavens [c.336 BCE], 279b12) |
| 395 | It seems possible that there exists a limited number of other worlds apart from this one [Aristotle] |
| Full Idea: One might indeed be puzzled whether, just as the world about us exists, nothing prevents there being others as well, certainly more than one, though not an unlimited number | |
| From: Aristotle (On the Heavens [c.336 BCE], 274a26) |