25 ideas
| 24032 | Clever scholars can obscure things which are obvious even to peasants [Descartes] |
| Full Idea: Scholars are usually ingenious enough to find ways of spreading darkness even in things which are obvious by themselves, and which the peasants are not ignorant of. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: Wonderful! I see it everywhere in philosophy. It is usually the result of finding ingenious and surprising grounds for scepticism. The amazing thing is not their lovely arguments, but that fools then take their conclusions seriously. Modus tollens. |
| 24033 | Most scholastic disputes concern words, where agreeing on meanings would settle them [Descartes] |
| Full Idea: The questions on which scholars argue are almost always questions of word. …If philosophers were agreed on the meaning of words, almost all their controversies would cease. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 13) | |
| A reaction: He has a low opinion of 'scholars'! It isn't that difficult to agree on the meanings of key words, in a given context. The aim isn't to get rid of the problems, but to focus on the real problems. Some words contain problems. |
| 22708 | Good reasons must give way to better [Shakespeare] |
| Full Idea: Good reasons must of force give way to better. | |
| From: William Shakespeare (Julius Caesar [1599], 4.3.205) | |
| A reaction: [Brutus to Cassius] This remark is an axiom of rationality. But, of course, reasons can come in groups, and three modest reasons may compete with one very good reason. |
| 24024 | The secret of the method is to recognise which thing in a series is the simplest [Descartes] |
| Full Idea: It is necessary, in a series of objects, to recognise which is the simplest thing, and how all the others depart from it. This rule contains the whole secret of the method. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 06) | |
| A reaction: This is an appealing thought, though deciding the criteria for 'simplest' looks tough. Are electrons, for example, simple? Is a person a simple basic thing? |
| 24018 | One truth leads us to another [Descartes] |
| Full Idea: One truth discovered helps us to discover another. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 01) | |
| A reaction: I take this to be one of the key ingredients of objectivity. People who know very little have almost no chance of objectivity. A mind full of falsehoods also blocks it. |
| 24035 | Unity is something shared by many things, so in that respect they are equals [Descartes] |
| Full Idea: Unity is that common nature in which all things that are compared with each other must participate equally. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 14) | |
| A reaction: A lovely explanation of the concept of 'units' for counting. Fregeans hate units, but we Grecian thinkers love them. |
| 24036 | I can only see the proportion of two to three if there is a common measure - their unity [Descartes] |
| Full Idea: I do not recognise what the proportion of magnitude is between two and three, unless I consider a third term, namely unity, which is the common measure of the one and the other. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 14) | |
| A reaction: A striking defence of the concept of the need for the unit in arithmetic. To say 'three is half as big again', you must be discussing the same size of 'half' in each instance. |
| 24029 | Among the simples are the graspable negations, such as rest and instants [Descartes] |
| Full Idea: Among the simple things, we must also place their negation and deprivation, insofar as they fall under out intelligence, because the idea of nothingness, of the instant, of rest, is no less true an idea than that of existence, of duration, of motion. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: He sees the 'simple' things as the foundation of all knowledge, because they are self-evident. Not sure about 'no less true', since the specific nothings are parasitic on the somethings. |
| 23647 | Objects have an essential constitution, producing its qualities, which we are too ignorant to define [Reid] |
| Full Idea: Individuals and objects have a real essence, or constitution of nature, from which all their qualities flow: but this essence our faculties do not comprehend. They are therefore incapable of definition. | |
| From: Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], 1) | |
| A reaction: Aha - he's one of us! I prefer the phrase 'essential nature' of an object, which is understood, I think, by everyone. I especially like the last bit, directed at those who mistakenly think that Aristotle identified the essence with the definition. |
| 24030 | 3+4=7 is necessary because we cannot conceive of seven without including three and four [Descartes] |
| Full Idea: When I say that four and three make seven, this connection is necessary, because one cannot conceive the number seven distinctly without including in it in a confused way the number four and the number three. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: This seems to make the truths of arithmetic conceptual, and hence analytic. |
| 11958 | Impossibilites are easily conceived in mathematics and geometry [Reid, by Molnar] |
| Full Idea: Reid pointed out how easily conceivable mathematical and geometric impossibilities are. | |
| From: report of Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], IV.III) by George Molnar - Powers 11.3 | |
| A reaction: The defence would be that you have to really really conceive them, and the only way the impossible can be conceived is by blurring it at the crucial point, or by claiming to conceive more than you actually can |
| 24019 | If we accept mere probabilities as true we undermine our existing knowledge [Descartes] |
| Full Idea: It is better never to study than to be unable to distinguish the true from the false, and be obliged to accept as certain what is doubtful. One risks losing the knowledge one already has. Hence we reject all those knowledges which are only probable. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 02) | |
| A reaction: This is usually seen nowadays (and I agree) that this is a false dichotomy. Knowledge can't be all-or-nothing. We should accept probabilities as probable, not as knowledge. Probability became a science after Descartes. |
| 24020 | We all see intuitively that we exist, where intuition is attentive, clear and distinct rational understanding [Descartes] |
| Full Idea: By intuition I mean the conception of an attentive mind, so distinct and clear that it has no doubt about what it understands, …a conception that is borne of the sole light of reason. Thus everyone can see intuitively that he exists. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 03) | |
| A reaction: By 'intuition' he means self-evident certainty, whereas my concept is of a judgement of which I am reasonably confident, but without sufficient grounds for certainty. This is an early assertion of the Cogito, with a clear statement of its grounding. |
| 24031 | When Socrates doubts, he know he doubts, and that truth is possible [Descartes] |
| Full Idea: If Socrates says he doubts everything, it necessarily follows that he at least understands that he doubts, and that he knows that something can be true or false: for these are notions that necessarily accompany doubt. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: An early commitment to the Cogito. But note that the inescapable commitment is not just to his existence, but also to his own reasoning, and his own commitment, and to the possibility of truth. Many, many things are undeniable. |
| 24025 | Clear and distinct truths must be known all at once (unlike deductions) [Descartes] |
| Full Idea: We require two conditions for intuition, namely that the proposition appear clear and distinct, and then that it be understood all at once and not successively. Deduction, on the other hand, implies a certain movement of the mind. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 11) | |
| A reaction: A nice distinction. Presumably with deduction you grasp each step clearly, and then the inference and conclusion, and you can then forget the previous steps because you have something secure. |
| 24022 | Our souls possess divine seeds of knowledge, which can bear spontaneous fruit [Descartes] |
| Full Idea: The human soul possesses something divine in which are deposited the first seeds of useful knowledge, which, in spite of the negligence and embarrassment of poorly done studies, bear spontaneous fruit. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 04) | |
| A reaction: This makes clear the religious underpinning which is required for his commitment to such useful innate ideas (such as basic geometry) |
| 24034 | If someone had only seen the basic colours, they could deduce the others from resemblance [Descartes] |
| Full Idea: Let there be a man who has sometimes seen the fundamental colours, and never the intermediate and mixed colours; it may be that by a sort of deduction he will represent those he has not seen, by their resemblance to the others. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 14) | |
| A reaction: Thus Descartes solved Hume's shade of blue problem, by means of 'a sort of deduction' from resemblance, where Hume was paralysed by his need to actually experience it. Dogmatic empiricism is a false doctrine! |
| 24021 | The method starts with clear intuitions, followed by a process of deduction [Descartes] |
| Full Idea: If the method shows clearly how we must use intuition to avoid mistaking the false for the true, and how deduction must operate to lead us to the knowledge of all things, it will be complete in my opinion. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 04) | |
| A reaction: A perfect statement of his foundationalist view. It needs a clear and distinct basis, and the steps of building must be strictly logical. Of course, most of our knowledge relies on induction, rather than deduction. |
| 24027 | Nerves and movement originate in the brain, where imagination moves them [Descartes] |
| Full Idea: The motive power or the nerves themselves originate in the brain, which contains the imagination, which moves them in a thousand ways, as the common sense is moved by the external sense. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: This sounds a lot more physicalist than his later explicit dualism in Meditations. Even in that work the famous passage on the ship's pilot acknowledged tight integration of mind and brain. |
| 24026 | Our four knowledge faculties are intelligence, imagination, the senses, and memory [Descartes] |
| Full Idea: There are four faculties in us which we can use to know: intelligence, imagination, the senses, and memory. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: Philosophers have to attribute faculties to the mind, even if the psychologists and neuroscientists won't accept them. We must infer the sources of our modes of understanding. He is cautious about imagination. |
| 24028 | The force by which we know things is spiritual, and quite distinct from the body [Descartes] |
| Full Idea: This force by which we properly know objects is purely spiritual, and is no less distinct from the body than is the blood from the bones. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: This firmly contradicts any physicalism I thought I detected in Idea 24027! He uses the word 'spiritual' of the mind here, which I don't think he uses in later writings. |
| 23646 | Reference is by name, or a term-plus-circumstance, or ostensively, or by description [Reid] |
| Full Idea: An individual is expressed by a proper name, or by a general word joined to distinguishing circumstances; if unknown, it may be pointed out to the senses; when beyond the reach of the senses it may be picked out by an imperfect but true description. | |
| From: Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], 1) | |
| A reaction: [compressed] If Putnam, Kripke and Donnellan had read this paragraph they could have save themselves a lot of work! I take reference to be the activity of speakers and writers, and these are the main tools of the trade. |
| 23645 | A word's meaning is the thing conceived, as fixed by linguistic experts [Reid] |
| Full Idea: The meaning of a word (such as 'felony') is the thing conceived; and that meaning is the conception affixed to it by those who best understand the language. | |
| From: Thomas Reid (Essays on Intellectual Powers 4: Conception [1785], 1) | |
| A reaction: He means legal experts. This is precisely that same as Putnam's account of the meaning of 'elm tree'. His discussion here of reference is the earliest I have encountered, and it is good common sense (for which Reid is famous). |
| 20304 | The cause of my action is in my will [Shakespeare] |
| Full Idea: The cause is in my will. I will not come./That is enough to satisfy the senate./But for your private satisfaction,/Because I love you, I will let you know. | |
| From: William Shakespeare (Julius Caesar [1599], II.ii) | |
| A reaction: This asserts the purest form of volitionism, but then qualifies it, because Caesar's will has been influenced by his wife's dreams. |
| 24023 | All the sciences searching for order and measure are related to mathematics [Descartes] |
| Full Idea: I have discovered that all the sciences which have as their aim the search for order and measure are related to mathematics. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 04) | |
| A reaction: Note that he sound a more cautious note than Galileo's famous remark. It leaves room for biology to still be a science, even when it fails to be mathematical. |