46 ideas
| 13838 | A decent modern definition should always imply a semantics [Hacking] |
| Full Idea: Today we expect that anything worth calling a definition should imply a semantics. | |
| From: Ian Hacking (What is Logic? [1979], §10) | |
| A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives. |
| 22309 | An idea can only be like another idea [Berkeley] |
| Full Idea: An idea can be like nothing but an idea. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §08), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 43 'Mean' | |
| A reaction: I take this to be relevant to the correspondence theory, but also to be one of Berkeley's best observations. We understand ideas, but we can't map them onto the world (because they are not maps!). ...But then how is one idea like another? Hm. |
| 13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
| Full Idea: 'Dilution' (or 'Thinning') provides an essential contrast between deductive and inductive reasoning; for the introduction of new premises may spoil an inductive inference. | |
| From: Ian Hacking (What is Logic? [1979], §06.2) | |
| A reaction: That is, inductive logic (if there is such a thing) is clearly non-monotonic, whereas classical inductive logic is monotonic. |
| 13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
| Full Idea: If A |- B and B |- C, then A |- C. This generalises to: If Γ|-A,Θ and Γ,A |- Θ, then Γ |- Θ. Gentzen called this 'cut'. It is the transitivity of a deduction. | |
| From: Ian Hacking (What is Logic? [1979], §06.3) | |
| A reaction: I read the generalisation as 'If A can be either a premise or a conclusion, you can bypass it'. The first version is just transitivity (which by-passes the middle step). |
| 13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
| Full Idea: Only the cut rule can have a conclusion that is less complex than its premises. Hence when cut is not used, a derivation is quite literally constructive, building up from components. Any theorem obtained by cut can be obtained without it. | |
| From: Ian Hacking (What is Logic? [1979], §08) |
| 13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
| Full Idea: I don't believe English is by nature classical or intuitionistic etc. These are abstractions made by logicians. Logicians attend to numerous different objects that might be served by 'If...then', like material conditional, strict or relevant implication. | |
| From: Ian Hacking (What is Logic? [1979], §15) | |
| A reaction: The idea that they are 'abstractions' is close to my heart. Abstractions from what? Surely 'if...then' has a standard character when employed in normal conversation? |
| 13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
| Full Idea: First-order logic is the strongest complete compact theory with a Löwenheim-Skolem theorem. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
| Full Idea: Henkin proved that there is no first-order treatment of branching quantifiers, which do not seem to involve any idea that is fundamentally different from ordinary quantification. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: See Hacking for an example of branching quantifiers. Hacking is impressed by this as a real limitation of the first-order logic which he generally favours. |
| 13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
| Full Idea: Second-order logic has no chance of a completeness theorem unless one ventures into intensional entities and possible worlds. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
| Full Idea: My doctrine is that the peculiarity of the logical constants resides precisely in that given a certain pure notion of truth and consequence, all the desirable semantic properties of the constants are determined by their syntactic properties. | |
| From: Ian Hacking (What is Logic? [1979], §09) | |
| A reaction: He opposes this to Peacocke 1976, who claims that the logical connectives are essentially semantic in character, concerned with the preservation of truth. |
| 13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
| Full Idea: For some purposes the variables of first-order logic can be regarded as prepositions and place-holders that could in principle be dispensed with, say by a system of arrows indicating what places fall in the scope of which quantifier. | |
| From: Ian Hacking (What is Logic? [1979], §11) | |
| A reaction: I tend to think of variables as either pronouns, or as definite descriptions, or as temporary names, but not as prepositions. Must address this new idea... |
| 13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
| Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos. |
| 6717 | Abstract ideas are impossible [Berkeley] |
| Full Idea: We have, I think, shown the impossibility of Abstract Ideas. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §21) | |
| A reaction: He achieves this by an attack on universals, offering the nominalist view that there are only particulars. There seems to be a middle ground, where universals don't actually exist, but there are settled conventional abstraction, beyond particulars. |
| 18876 | Berkeley does believe in trees, but is confused about what trees are [Berkeley, by Cameron] |
| Full Idea: I think that we should consider Berkeley as believing in trees; we should simply claim that he has false beliefs about what trees are. | |
| From: report of George Berkeley (The Principles of Human Knowledge [1710]) by Ross P. Cameron - Truthmakers, Realism and Ontology 'Realism' | |
| A reaction: I can be realist about spots before my eyes, or a ringing in my ears, but be (quite sensibly) unsure about what they are, so Cameron's suggestion sounds plausible. |
| 3291 | Emergent properties appear at high levels of complexity, but aren't explainable by the lower levels [Nagel] |
| Full Idea: The supposition that a diamond or organism should truly have emergent properties is that they appear at certain complex levels of organisation, but are not explainable (even in principle) in terms of any more fundamental properties of the system. | |
| From: Thomas Nagel (Panpsychism [1979], p.186) |
| 6715 | Universals do not have single meaning, but attach to many different particulars [Berkeley] |
| Full Idea: There is no such thing as one precise and definite signification annexed to any general name, they all signifying indifferently a great number of particular ideas. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §18) | |
| A reaction: The term 'red' may be assigned to a range of colours, but we also recognise the precision of 'that red'. For 'electron', or 'three', or 'straight', the particulars are indistinguishable. |
| 6719 | No one will think of abstractions if they only have particular ideas [Berkeley] |
| Full Idea: He that knows he has no other than particular ideas, will not puzzle himself in vain to find out and conceive the abstract idea annexed to any name. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §24) | |
| A reaction: A nice point against universals. Maybe gods only think in particulars. One particular on its own could never suggest a universal. How are you going to spot patterns if you don't think in universals? Maths needs patterns. |
| 6714 | Universals do not have any intrinsic properties, but only relations to particulars [Berkeley] |
| Full Idea: Universality, so far as I can comprehend it, does not consist in the absolute, positive nature or conception of anything, but in the relation it bears to the particulars signified or represented by it. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §15) | |
| A reaction: I always think it is a basic principle in philosophy that some sort of essence must precede relations (and functions). What is it about universals that enables them to have a relation to particulars? |
| 6729 | Material substance is just general existence which can have properties [Berkeley] |
| Full Idea: The most accurate philosophers have no other meaning annexed to 'material substance' but the idea of being in general, together with the relative notion of its supporting accidents. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §17) | |
| A reaction: This is part of the attack on Aristotle's concept of 'substance', and is a nice way of dissolving the concept. 'Substance' will never reappear in physics, but modern philosopher have returned to it, as possibly inescapable in metaphysics. |
| 16636 | A die has no distinct subject, but is merely a name for its modes or accidents [Berkeley] |
| Full Idea: To me a die seems to be nothing distinct from those things which are termed its modes or accidents. And to say a die is hard, extended and square is not to attribute those qualities to a distinct subject, but only an explication of the word 'die'. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], n 49) | |
| A reaction: This is apparently a reaction to Locke, and a final rejection of the medieval idea of a 'substance'. Unfortunately it leaves Berkeley with a 'bundle' view of objects (a typical empiricist account), which is even worse. |
| 6722 | Perception is existence for my table, but also possible perception, by me or a spirit [Berkeley] |
| Full Idea: The table I write on I say exists, that is, I see and feel it; and if I were out of my study I should say it existed - meaning thereby that if I was in my study I might perceive it, or that some other spirit actually does perceive it. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §3) | |
| A reaction: Berkeley is always (understandably) labelled as an 'idealist', but this seems to be what we call 'phenomenalism', because it allows possible experiences as well as actual ones. See Ideas 5170 and 6522. |
| 6724 | The only substance is spirit, or that which perceives [Berkeley] |
| Full Idea: It is evident that there is not any other Substance than spirit, or that which perceives. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §7) | |
| A reaction: Weird. To say that this is 'evident' seems to be begging the question. Why should he assume that there is nothing more to reality than his perception of it? He seems strangely unimaginative. |
| 6723 | The 'esse' of objects is 'percipi', and they can only exist in minds [Berkeley] |
| Full Idea: The absolute existence of unthinking things with no relation to their being perceived is unintelligible to me; their 'esse' is 'percipi', nor is it possible they should have any existence out of the minds or thinking things which perceive them. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §3) | |
| A reaction: "Esse est percipi" (to be is to be perceived) is the well-known slogan associated with Berkeley. I cannot see how Berkeley can assert that the separate existence of things is impossible. He is the classic confuser of epistemology and ontology. |
| 6732 | When I shut my eyes, the things I saw may still exist, but in another mind [Berkeley] |
| Full Idea: When I shut my eyes, the things I saw may still exist, but it must be in another mind. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §90) | |
| A reaction: This strikes me as ridiculous. What kind of theory says that a table goes out of existence when someone forgets to look at it for a moment, but is then recreated in identical form? Epistemology is not ontology. |
| 6726 | No one can, by abstraction, conceive extension and motion of bodies without sensible qualities [Berkeley] |
| Full Idea: I desire any one to reflect and try whether he can, by any abstraction of thought, conceive the extension and motion of a body without any sensible qualities. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §10) | |
| A reaction: The rather geometrical view of objects found in Descartes and Russell is an attempt to do this. I don't think the fact that we can't really achieve it matters much. We divide primary from secondary qualities in our understanding, not in experience. |
| 6728 | Motion is in the mind, since swifter ideas produce an appearance of slower motion [Berkeley] |
| Full Idea: Is it not reasonable to say that motion is not without the mind, since if the succession of ideas in the mind become swifter the motion, it is acknowledged, shall appear slower without any alteration in any external object. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §14) | |
| A reaction: An intriguing argument, based on what is now the principle of slow-motion photography. Fast minds slow down movement, like great tennis players. By what right does Berkeley say that the external subject is unaltered? |
| 6727 | Figure and extension seem just as dependent on the observer as heat and cold [Berkeley] |
| Full Idea: If heat and cold are only affections of the mind (since the same body seems cold to one hand and warm to the other), why may we not argue that figure and extension also appear different to the same eye at different stations? | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §14) | |
| A reaction: If the assessment of the qualities of an object is entirely a matter of our experiences of it, there is no denying Berkeley on this. However, judgement goes beyond experience, into speculations, inferences, and explanations. |
| 6495 | Berkeley's idealism resulted from fear of scepticism in representative realism [Robinson,H on Berkeley] |
| Full Idea: It was fear of scepticism based upon representative realism that motivated Berkeley's idealism. | |
| From: comment on George Berkeley (The Principles of Human Knowledge [1710]) by Howard Robinson - Perception II.1 | |
| A reaction: Personally I side with Russell, who accepts representative realism, and also accepts that some degree of scepticism is unavoidable, but without getting excited about it. The key to everything is to be a 'fallibilist' about knowledge. |
| 6720 | Knowledge is of ideas from senses, or ideas of the mind, or operations on sensations [Berkeley] |
| Full Idea: The objects of knowledge are either ideas imprinted on the senses, or passions and operations of the mind, or ideas (formed by memory and imagination) compounding, dividing or barely representing the original perceptions. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §1) | |
| A reaction: This is the germ of Hume's 'associations' (Idea 2189). There is not much room here for synthetic a priori knowledge, as the a priori part seems to merely know the mind. Most of Russell's epistemology is contained in the last part of the sentence. |
| 23636 | Berkeley's idealism gives no grounds for believing in other minds [Reid on Berkeley] |
| Full Idea: I can find no principle in Berkeley's system, which affords me even probable ground to conclude that there are other intelligent beings, like myself. | |
| From: comment on George Berkeley (The Principles of Human Knowledge [1710]) by Thomas Reid - Essays on Intellectual Powers 2: Senses 10 | |
| A reaction: I agree, which means that Berkeley's position seems to entail solipsism, unless God is the Cartesian deus ex machina who rescues him from this wall of ignorance. |
| 6736 | I know other minds by ideas which are referred by me to other agents, as their effects [Berkeley] |
| Full Idea: The knowledge I have of other spirits is not immediate, as is the knowledge of my ideas; but depending on the intervention of ideas, by me referred to agents or spirits distinct from myself, as effects or concomitant signs. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §145) | |
| A reaction: This strikes me as gross intellectual dishonesty, since the argument Berkeley uses to assert other minds could equally be used to assert the existence of tables ('by me referred to agents distinct from myself, as effects'). Be a solipsist or a realist. |
| 6713 | If animals have ideas, and are not machines, they must have some reason [Berkeley] |
| Full Idea: If the brutes have any ideas at all, and are not bare machines (as some would have them), we cannot deny them to have some reason. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §11) | |
| A reaction: It seems possible to imagine a low level of mind, where a few ideas (or concepts) float around, but hardly anything worth the name of reason. However, a Darwinian view suggests that concepts must bestow an advantage, so the two go together. |
| 6491 | Berkeley replaced intentionality with an anti-abstractionist imagist theory of thought [Berkeley, by Robinson,H] |
| Full Idea: By Berkeley - with his anti-abstractionism and imagist theory of thought - the classical sense-datum conception was firmly established, and intentionality had disappeared as an intrinsic property, not only of perceptual states, but of all mental contents. | |
| From: report of George Berkeley (The Principles of Human Knowledge [1710]) by Howard Robinson - Perception 1.6 | |
| A reaction: Intentionality was originally a medieval concept, and was revived by Brentano in the late nineteenth century. Nowadays intentionality is taken for granted, but I still suspect that we could drop it, and talk of nothing but brain states caused by reality. |
| 6711 | The mind creates abstract ideas by considering qualities separated from their objects [Berkeley] |
| Full Idea: We are told that the mind being able to consider each quality of things singly, or abstracted from those other qualities with which it is united, does by that means frame to itself abstract ideas. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §7) | |
| A reaction: A helpful explanation of 'abstract' ideas. Berkeley gives colour and movement as examples. Fodor suggests that abstraction is the key strategy in empiricist epistemology. The difficulty is to decide whether the qualities are natural or conventional. |
| 10581 | I can only combine particulars in imagination; I can't create 'abstract' ideas [Berkeley] |
| Full Idea: Whether others can abstract their ideas, they best can tell. For myself, I find I have a faculty of imagining, or representing to myself, only the idea of those particular things I have perceived, and of compounding and dividing them. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], 10) | |
| A reaction: He is admitting mixing experiences, but always particulars, never abstract. His examples are 'man' and 'motion'. Compare Aristotle Idea 9067. Berkeley is, I think, trapped in a false imagistic view of thought. My image of Plato blurs young and old. |
| 6721 | Ideas are perceived by the mind, soul or self [Berkeley] |
| Full Idea: The thing which knows or perceives ideas is what I call mind, spirit, soul or myself. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §2) | |
| A reaction: The interest here is in making no distinction between 'mind' and 'self', which seems to ally Berkeley with Locke's view of personal identity, as continuity of consciousness. The addition of 'soul' tries to connect Locke to Christian thought. |
| 6716 | Language is presumably for communication, and names stand for ideas [Berkeley] |
| Full Idea: It is a received opinion that language has no other end but the communicating our ideas, and that every significant name stands for an idea. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §19) | |
| A reaction: This attitude to language has been widely discredited, partly by the observation that 'idea' is very ambiguous, and partly by the fans of meaning-as-use. Truth conditions seem to be ideas, and so are speaker's intentions. |
| 6718 | I can't really go wrong if I stick to wordless thought [Berkeley] |
| Full Idea: So long as I confine my thoughts to my own ideas divested of words, I do not see how I can easily be mistaken. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], Intro §22) | |
| A reaction: I think it was one of the great errors of twentieth century philosophy to say that Berkeley cannot do this, because thought needs language. Personally I think language lags along behind most our thinking, tidying up the mess. I believe in propositions. |
| 6731 | No one can explain how matter affects mind, so matter is redundant in philosophy [Berkeley] |
| Full Idea: How matter should operate on a spirit, or produce any idea in it, is what no philosopher will pretend to explain; it is therefore evident there can be no use of matter in natural philosophy. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §50) | |
| A reaction: An intriguing argument for idealism, which starts in Cartesian dualism, but then discards the physical world because of the notorious interaction problem. Of course, if he had thought that matter and spirit were one (Spinoza) the problem vanishes. |
| 6730 | We discover natural behaviour by observing settled laws of nature, not necessary connections [Berkeley] |
| Full Idea: That food nourishes, sleep refreshes, and fire warms us; all this we know, not by discovering any necessary connexion between our ideas, but only by the observation of the settled laws of nature. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §31) | |
| A reaction: Hume is famous for this idea, but it is found in Hobbes too (Idea 2364), and is the standard empiricist view of causation. The word 'settled' I take to imply that the laws are contingent, because they could become unsettled at any time. |
| 3290 | Given the nature of heat and of water, it is literally impossible for water not to boil at the right heat [Nagel] |
| Full Idea: Given what heat is and what water is, it is literally impossible for water to be heated beyond a certain point at normal atmospheric pressure without boiling. | |
| From: Thomas Nagel (Panpsychism [1979], p.186) |
| 15861 | The laws of nature are mental regularities which we learn by experience [Berkeley] |
| Full Idea: The set rules or established methods wherein the Mind we depend on excites in us the ideas of sense, are called the 'laws of nature'; and these we learn by experience, which teaches us that such and such ideas are attended with certain other ideas. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], 33) | |
| A reaction: He observes that the ideas of sense are more regular than other mental events, and attributes the rules to an Author. He is giving the standard empirical Humean view, with his own quirky idealist slant. |
| 6734 | If properties and qualities arise from an inward essence, we will remain ignorant of nature [Berkeley] |
| Full Idea: An inducement to pronouncing ourselves ignorant of the nature of things is the opinion that everything includes within itself the cause of its properties; or that there is in each object an inward essence which is the source whence its qualities flow. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §102) | |
| A reaction: This remains a good objection to essentialism - that while it remains quite a plausible picture of how nature operates, it makes the task of understanding nature hopeless. We can grasp imposed regular laws, but not secret inner essences. |
| 6735 | All motion is relative, so a single body cannot move [Berkeley] |
| Full Idea: There cannot be any motion other than relative; …if there was one only body in being it could not possibly move. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §112) | |
| A reaction: This seems to agree with with Leibniz in denying the Newton-Clarke idea of absolute space. See Idea 2100. Suppose there were two bodies racing towards one another, when one of them suddenly vanished? |
| 6733 | I cannot imagine time apart from the flow of ideas in my mind [Berkeley] |
| Full Idea: Whenever I attempt to frame a simple idea of time, abstracted from the succession of ideas in my mind, which flows uniformly and is participated in by all beings, I am lost and embrangled in inextricable difficulties. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §98) | |
| A reaction: 'Embrangled'! A nice statement of the idealist view of time, as entirely mental. I know what he means. However, surely he can manage to imagine a movement which continues when he shuts he eyes? Try blinking during a horse race. |
| 6737 | Particular evils are really good when linked to the whole system of beings [Berkeley] |
| Full Idea: Those particular things which, considered in themselves, appear to be evil, have the nature of good, when considered as linked with the whole system of beings. | |
| From: George Berkeley (The Principles of Human Knowledge [1710], §153) | |
| A reaction: This wildly contradicts the rest of Berkeley's philosophy, which is strictly empiricist, and rests wholly on actual experience. What experience does he have of the 'whole system of beings', and its making evil into actual good? |