48 ideas
2056 | Philosophers are always switching direction to something more interesting [Plato] |
Full Idea: Philosophers are always ready to change direction, if a topic crops up which is more attractive than the one to hand. | |
From: Plato (Theaetetus [c.368 BCE], 172d) | |
A reaction: Which sounds trivial, but it may be what God does. |
2086 | Understanding mainly involves knowing the elements, not their combinations [Plato] |
Full Idea: A perfect grasp of any subject depends far more on knowing elements than on knowing complexes. | |
From: Plato (Theaetetus [c.368 BCE], 206b) |
2083 | Either a syllable is its letters (making parts as knowable as whole) or it isn't (meaning it has no parts) [Plato] |
Full Idea: Either a syllable is not the same as its letters, in which case it cannot have the letters as parts of itself, or it is the same as its letters, in which case these basic elements are just as knowable as it is. | |
From: Plato (Theaetetus [c.368 BCE], 205b) |
2082 | A rational account is essentially a weaving together of things with names [Plato] |
Full Idea: Just as primary elements are woven together, so their names may be woven together to produce a spoken account, because an account is essentially a weaving together of names. | |
From: Plato (Theaetetus [c.368 BCE], 202b) | |
A reaction: If justification requires 'logos', and logos is a 'weaving together of names', then Plato might be taken as endorsing the coherence account of justification. Or do the two 'weavings' correspond? |
2052 | Eristic discussion is aggressive, but dialectic aims to help one's companions in discussion [Plato] |
Full Idea: Eristic discussions involve as many tricks and traps as possible, but dialectical discussions involve being serious and correcting the interlocutor's mistakes only when they are his own fault or the result of past conditioning. | |
From: Plato (Theaetetus [c.368 BCE], 167e) |
15854 | A primary element has only a name, and no logos, but complexes have an account, by weaving the names [Plato] |
Full Idea: A primary element cannot be expressed in an account; it can only be named, for a name is all that it has. But with the things composed of these ...just as the elements are woven together, so the names can woven to become an account. | |
From: Plato (Theaetetus [c.368 BCE], 202b01-3) | |
A reaction: This is the beginning of what I see as Aristotle's metaphysics, as derived from his epistemology, that is, ontology is what explains, and what we can give an account [logos] of. Aristotle treats this under 'definitions'. |
10216 | We master arithmetic by knowing all the numbers in our soul [Plato] |
Full Idea: It must surely be true that a man who has completely mastered arithmetic knows all numbers? Because there are pieces of knowledge covering all numbers in his soul. | |
From: Plato (Theaetetus [c.368 BCE], 198b) | |
A reaction: This clearly views numbers as objects. Expectation of knowing them all is a bit startling! They also appear to be innate in us, and hence they appear to be Forms. See Aristotle's comment in Idea 645. |
2060 | There seem to be two sorts of change: alteration and motion [Plato] |
Full Idea: There are two kinds of change, I think: alteration and motion. | |
From: Plato (Theaetetus [c.368 BCE], 181d) | |
A reaction: Idea 1700 is better than this. |
2084 | If a word has no parts and has a single identity, it turns out to be the same kind of thing as a letter [Plato] |
Full Idea: If a complex or a syllable has no parts and is a single identity, hasn't it turned out to be the same kind of thing as an element or letter? | |
From: Plato (Theaetetus [c.368 BCE], 205d) |
15844 | A sum is that from which nothing is lacking, which is a whole [Plato] |
Full Idea: But this sum now - isn't it just when there is nothing lacking that it is a sum? Yes, necessarily. And won't this very same thing - that from which nothing is lacking - be a whole? | |
From: Plato (Theaetetus [c.368 BCE], 205a) | |
A reaction: This seems to be right, be rather too vague and potentially circular to be of much use. What is the criterion for deciding that nothing is lacking? |
15843 | The whole can't be the parts, because it would be all of the parts, which is the whole [Plato] |
Full Idea: The whole does not consist of parts; for it did, it would be all the parts and so would be the sum. | |
From: Plato (Theaetetus [c.368 BCE], 204e) | |
A reaction: That is, 'the whole is the sum of its parts' is a tautology! The claim that 'the whole is more than the sum of its parts' gets into similar trouble. See Verity Harte on this. |
11842 | If short-lived happenings like car crashes are 'events', why not long-lived events like Dover Cliffs? [Broad] |
Full Idea: We call a lightning flash or a motor accident an event, but refuse to apply this to the cliffs of Dover. ...But quantitative differences (of time) give no good grounds for calling one bit of history an event, and refusing the name to another bit. | |
From: C.D. Broad (Scientific Thought [1923], p.54), quoted by David Wiggins - Sameness and Substance Renewed 2.3 n13 | |
A reaction: Wiggins calls this proposal a 'terrible absurdity', but it seems to me to demand attention. There is a case to be made for a 'process' to be the fundamental category of our ontology, with stable physical objects seen in that light. |
14759 | A thing is simply a long event, linked by qualities, and spatio-temporal unity [Broad] |
Full Idea: A thing is simply a long event, throughout the course of which there is either qualitative similarity or continuous qualitative change, together with a characteristic spatio-temporal unity. | |
From: C.D. Broad (Scientific Thought [1923], 10 'Duration') | |
A reaction: At least he is trying to give some sort of principle that links the stages of the event together. |
2080 | Things are only knowable if a rational account (logos) is possible [Plato] |
Full Idea: Things which are susceptible to a rational account are knowable. | |
From: Plato (Theaetetus [c.368 BCE], 201d) |
16126 | Expertise is knowledge of the whole by means of the parts [Plato] |
Full Idea: A man has passed from mere judgment to expert knowledge of the being of a wagon when he has done so in virtue of having gone over the whole by means of the elements. | |
From: Plato (Theaetetus [c.368 BCE], 207c) | |
A reaction: Plato is emphasising that the expert must know the hundred parts of a wagon, and not just the half dozen main components, but here the point is to go over the whole via the parts, and not just list the parts. |
2050 | It is impossible to believe something which is held to be false [Plato] |
Full Idea: It is impossible to believe something which is not the case. | |
From: Plato (Theaetetus [c.368 BCE], 167a) |
2076 | How can a belief exist if its object doesn't exist? [Plato] |
Full Idea: If the object of a belief is what is not, the object of this belief is nothing; but if there is no object to a belief, then that is not belief at all. | |
From: Plato (Theaetetus [c.368 BCE], 189a) |
2045 | Perception is infallible, suggesting that it is knowledge [Plato] |
Full Idea: Perception is always of something that is, and it is infallible, which suggests that it is knowledge. | |
From: Plato (Theaetetus [c.368 BCE], 152c) |
2067 | Our senses could have been separate, but they converge on one mind [Plato] |
Full Idea: It would be peculiar if each of us were like a Trojan horse, with a whole bunch of senses sitting inside us, rather than that all these perceptions converge onto a single identity (mind, or whatever one ought to call it). | |
From: Plato (Theaetetus [c.368 BCE], 184d) |
2068 | With what physical faculty do we perceive pairs of opposed abstract qualities? [Plato] |
Full Idea: With what physical faculty do we perceive being and not-being, similarity and dissimilarity, identity and difference, oneness and many, odd and even and other maths, ….fineness and goodness? | |
From: Plato (Theaetetus [c.368 BCE], 185d) |
2069 | Thought must grasp being itself before truth becomes possible [Plato] |
Full Idea: If you can't apprehend being you can't apprehend truth, and so a thing could not be known. Therefore knowledge is not located in immediate experience but in thinking about it, since the latter makes it possible to grasp being and truth. | |
From: Plato (Theaetetus [c.368 BCE], 186c) |
2078 | You might mistake eleven for twelve in your senses, but not in your mind [Plato] |
Full Idea: Sight or touch might make someone take eleven for twelve, but he could never form this mistaken belief about the contents of his mind. | |
From: Plato (Theaetetus [c.368 BCE], 195e) |
2089 | An inadequate rational account would still not justify knowledge [Plato] |
Full Idea: If you don't know which letters belong together in the right syllables…it is possible for true belief to be accompanied by a rational account and still not be entitled to the name of knowledge. | |
From: Plato (Theaetetus [c.368 BCE], 208b) | |
A reaction: In each case of justification there is a 'clinching' stage, for which there is never going to be a strict rule. It might be foundational, but equally it might be massive coherence, or no alternative. |
2085 | Parts and wholes are either equally knowable or equally unknowable [Plato] |
Full Idea: Either a syllable and its letters are equally knowable and expressible in a rational account, or they are both equally unknowable and inexpressible. | |
From: Plato (Theaetetus [c.368 BCE], 205e) | |
A reaction: Presumably you could explain the syllable by the letters, but not vice versa, but he must mean that the explanation is worthless without the letters being explained too. So all explanation is worthless? |
2091 | Without distinguishing marks, how do I know what my beliefs are about? [Plato] |
Full Idea: If I only have beliefs about Theaetetus when I don't know his distinguishing mark, how on earth were my beliefs about you rather than anyone else? | |
From: Plato (Theaetetus [c.368 BCE], 209b) | |
A reaction: This is a rather intellectualist approach to mental activity. Presumably Theaetetus has lots of distinguishing marks, but they are not conscious. Must Socrates know everything? |
2087 | A rational account might be seeing an image of one's belief, like a reflection in a mirror [Plato] |
Full Idea: A rational account might be forming an image of one's belief, as in a mirror or a pond. | |
From: Plato (Theaetetus [c.368 BCE], 206d) | |
A reaction: Not promising, since the image is not going to be clearer than the original, or contain any new information. Maybe it would be clarified by being 'framed', instead of drifting in muddle. |
2090 | A rational account involves giving an image, or analysis, or giving a differentiating mark [Plato] |
Full Idea: A third sort of rational account (after giving an image, or analysing elements) is being able to mention some mark which differentiates the object in question ('the sun is the brightest heavenly body'). | |
From: Plato (Theaetetus [c.368 BCE], 208c) | |
A reaction: This is Plato's clearest statement of what would be involved in adding the necessary logos to your true belief. An image of it, or an analysis, or an individuation. How about a cause? |
2081 | Maybe primary elements can be named, but not receive a rational account [Plato] |
Full Idea: Maybe the primary elements of which things are composed are not susceptible to rational accounts. Each of them taken by itself can only be named, but nothing further can be said about it. | |
From: Plato (Theaetetus [c.368 BCE], 201e) | |
A reaction: This still seems to be more or less the central issue in philosophy - which things should be treated as 'primitive', and which other things are analysed and explained using the primitive tools? |
2088 | A rational account of a wagon would mean knowledge of its hundred parts [Plato] |
Full Idea: In the case of a wagon, we may only have correct belief, but someone who is able to explain what it is by going through its hundred parts has got hold of a rational account. | |
From: Plato (Theaetetus [c.368 BCE], 207b) | |
A reaction: A wonderful example. In science, you know smoking correlates with cancer, but you only know it when you know the mechanism, the causal structure. This may be a general truth. |
2047 | What evidence can be brought to show whether we are dreaming or not? [Plato] |
Full Idea: What evidence could be brought if we were asked at this very moment whether we are asleep and are dreaming all our thoughts? | |
From: Plato (Theaetetus [c.368 BCE], 158b) |
2054 | Clearly some people are superior to others when it comes to medicine [Plato] |
Full Idea: In medicine, at least, most people are not self-sufficient at prescribing and effecting cures for themselves, and here some people are superior to others. | |
From: Plato (Theaetetus [c.368 BCE], 171e) |
2059 | How can a relativist form opinions about what will happen in the future? [Plato] |
Full Idea: Does a relativist have any authority to decide about things which will happen in the future? | |
From: Plato (Theaetetus [c.368 BCE], 178c) | |
A reaction: Nice question! It seems commonsense that such speculations are possible, but without a concept of truth they are ridiculous. |
2053 | If you claim that all beliefs are true, that includes beliefs opposed to your own [Plato] |
Full Idea: To say that everyone believes what is the case, is to concede the truth of the oppositions' beliefs; in other words, the person has to concede that he himself is wrong. | |
From: Plato (Theaetetus [c.368 BCE], 171a) |
7621 | Special relativity, unlike general relativity, was operationalist in spirit [Putnam on Einstein] |
Full Idea: Einstein's interpretation of special relativity was operationalist in spirit (in marked contrast to the interpretation he gave to general relativity). | |
From: comment on Albert Einstein (works [1915]) by Hilary Putnam - Reason, Truth and History Ch.5 | |
A reaction: The late twentieth century was polluted with daft relativism, and I hold Einstein partly responsible, suspecting that he was a bad philosopher. The later development of Einstein's view noted here is interesting. |
22955 | Einstein took causation to be the bedrock of physics [Einstein, by Coveney/Highfield] |
Full Idea: It is difficult to overplay Einstein's commitment to the concept of causality as the bedrock of physics. | |
From: report of Albert Einstein (works [1915]) by P Coveney / R Highfield - The Arrow of Time 3 'problem' | |
A reaction: I normally avoid arguments from authority, but this carries a bit of weight (e.g. when Russell tries to oppose it). What happens to Einstein's theories if you remove causation from them? |
20638 | General relativity assumes laws of nature are the same in all frames of reference [Einstein, by Close] |
Full Idea: Einstein came to general relativity from the principles that the laws of nature are the same in all frames of reference. | |
From: report of Albert Einstein (works [1915]) by Frank Close - Theories of Everything 5 'Cosmological' | |
A reaction: I wish physicists would tell us a bit more about the ontological status of the 'laws of nature'. Presumably they are not supernatural, so there is an aspect of nature which is constant in all frames of reference. Explanation please. |
20636 | Newton is a special case of Einstein's general theory, with an infinite speed of light [Einstein, by Close] |
Full Idea: Einstein's general relativity included Newton's theory as a special case: Newton's theory corresponds to the speed of light being infinite relative to the speed of the interacting bodies. | |
From: report of Albert Einstein (works [1915]) by Frank Close - Theories of Everything 5 'Gravity' | |
A reaction: So Newton's theory was NOT wrong, but he made the false assumption that the speed of light was infinite. |
21230 | The theory is 'special' because it sticks to observers moving straight, at constant speeds [Einstein, by Farmelo] |
Full Idea: Einstein's first theory is 'special' because it only deals with observers who move in a straight line at constant speeds with respect to one another. | |
From: report of Albert Einstein (works [1915]) by Graham Farmelo - The Strangest Man 03 | |
A reaction: Most theories of this period seem to have focused on the simplest cases, for obvious reasons. |
21231 | Assume the speed of light is constant for all observers, and the laws of physics are the same [Einstein, by Farmelo] |
Full Idea: Einstein assumed that when each observer measures the speed of light in a vacuum, they find the same value, regardless of their speed; and that measurements will lead to agreement on the laws of physics. | |
From: report of Albert Einstein (works [1915]) by Graham Farmelo - The Strangest Man 03 | |
A reaction: So are the laws of physics constant for all observers, irrespective of their speed? |
20634 | General Relativity says there is no absolute force or acceleration [Einstein, by Close] |
Full Idea: Einstein's General Theory arose from the idea that there is no absolute measure of force and acceleration. | |
From: report of Albert Einstein (works [1915]) by Frank Close - Theories of Everything 5 'Gravity' | |
A reaction: If absolutely everything is only true relative to something else you wonder what the point of measuring anything is. How big can a 'frame of reference' or 'inertial frame' be. Is the multiverse a frame of reference? |
20648 | Mass is a measure of energy content [Einstein] |
Full Idea: The mass of a body is the measure of its energy content. | |
From: Albert Einstein (works [1915]), quoted by Peter Watson - Convergence 04 'Intro' | |
A reaction: If I knew what energy was, this would be very illuminating. This idea is e=mc^2 in words. We now have the Higgs field to consider when trying to understand mass. |
21232 | Space-time arises from the connection between measurements of space and of time [Einstein, by Farmelo] |
Full Idea: Einstein noted that the measurements of space and time are not independent but inextricably linked, leading to the idea of unified space-time (introduced by his former teacher Minkowski). | |
From: report of Albert Einstein (works [1915]) by Graham Farmelo - The Strangest Man 03 | |
A reaction: Notice the instrumentalist assumptions behind this. |
8160 | The present and past exist, but the future does not [Broad, by Dummett] |
Full Idea: Not only the present but also the past exist, but the future (so long as it is the future) does not. | |
From: report of C.D. Broad (Scientific Thought [1923]) by Michael Dummett - Thought and Reality 1 | |
A reaction: This is quite appealing, and seems right if you believe that every truth has a truthmaker, and that there are no truths about the future. And yet the whole misery of people dying is that they cease to exist. |
14609 | We could say present and past exist, but not future, so that each event adds to the total history [Broad] |
Full Idea: One theory accepts the reality of the present and the past, but holds that the future is simply nothing at all. Nothing has happened to the present by becoming past except that fresh slices of existence have been added to the total history of the world. | |
From: C.D. Broad (Scientific Thought [1923], II) | |
A reaction: This is now known as Broad's 'Growing Block' view of time. It is tempting to say that neither past nor future exist, but it seems undeniable that statements about the past can be wholly true, unlike those about the future. |
22933 | We imagine the present as a spotlight, moving across events from past to future [Broad] |
Full Idea: We imagine presentness moving, like the spot of light from a policeman's bulls eye traversing the fronts of houses in a street. What is illuminated is present, what was illuminated is past, and what is not yet illuminated is the future. | |
From: C.D. Broad (Scientific Thought [1923], II) | |
A reaction: This is the 'moving spotlight' compromise theory, which retains the B-series eternal sequence of ordered events, but adds the A-series privileged present moment. Le Poidevin says Broad represents time twice over. |
2058 | God must be the epitome of goodness, and we can only approach a divine state by being as good as possible [Plato] |
Full Idea: It is impossible for God to be immoral and not to be the acme of morality; and the only way any of us can approximate to God is to become as moral as possible. | |
From: Plato (Theaetetus [c.368 BCE], 176c) |
7626 | I do not believe in a personal God [Einstein] |
Full Idea: I do not believe in a personal God and I have never denied this but have expressed it clearly. | |
From: Albert Einstein (works [1915]), quoted by Richard Dawkins - The God Delusion Ch.1.15 | |
A reaction: This is an important corrective to those who claim Einstein as religious, on the basis of remarks about God not playing dice etc. See the whole of Dawkins's chapter on Einstein for full discussion. |
2057 | There must always be some force of evil ranged against good [Plato] |
Full Idea: The elimination of evil is impossible, Theodorus; there must always be some force ranged against good. | |
From: Plato (Theaetetus [c.368 BCE], 176a) |