| 5685 | True ideas are images, such as of a man, a chimera, or God [Descartes] |
| Full Idea: Some of my thoughts are like images of things; to these alone does the word 'idea' properly apply, as when I think of a man, or a chimera, or the sky, or an angel, or God. | |
| From: René Descartes (Meditations [1641], §3.37) | |
| A reaction: Descartes is obviously aware of a problem with the application of the word 'idea'. This definition seems rather narrow (and visual), but it is certainly confined to concepts, and does not expand to include propositions. |
| 21807 | Ideas are powerful entities, which can produce further ideas [Spinoza, by Schmid] |
| Full Idea: Spinoza conceives of ideas as intrinsically powerful entities, which have a capacity to produce further ideas. | |
| From: report of Baruch de Spinoza (The Ethics [1675]) by Stephan Schmid - Faculties in Early Modern Philosophy 6 | |
| A reaction: Is the idea the source of the entire philosophy of Hegel? I find Hegel's claim to infer huge chains of ideas from very simple origins quite implausible. I also rather doubt whether a wholly isolated idea can produce a further idea. |
| 4830 | An 'idea' is a mental conception which is actively formed by the mind in thinking [Spinoza] |
| Full Idea: By 'idea', I mean the mental conception which is formed by the mind as a thinking thing (this is not a passive perception with regard to the object, but expresses an activity of the mind). | |
| From: Baruch de Spinoza (The Ethics [1675], II Def 3) | |
| A reaction: This is interesting as a seventeenth century attempt to grapple with the nature of thought. Spinoza sees it as of the essence of mind, since it is what the mind contributes, rather than what happens to the mind when it experiences. |
| 4842 | Ideas are not images formed in the brain, but are the conceptions of thought [Spinoza] |
| Full Idea: By ideas I do not mean images such as are formed at the back of the eye, or in the midst of the brain, but the conceptions of thought. | |
| From: Baruch de Spinoza (The Ethics [1675], II Pr 48) | |
| A reaction: This appears to be equating 'ideas' with what we now call 'concepts', which presumably makes Spinoza less open to criticism than other philosophers of his time, for postulating baffling mental copies of the world. |
| 20311 | An idea involves affirmation or negation [Spinoza] |
| Full Idea: An idea, insofar as it is an idea, involves an affirmation or negation. | |
| From: Baruch de Spinoza (The Ethics [1675], II Pr 49 sII) | |
| A reaction: Spinoza clearly distinguishes ideas from images, and here seems to identify ideas with propositions. Nowadays we say these are 'true or false', but Spinoza is more personal and psychological. I prefer his way of putting it. |
| 6486 | Ideas are the objects of understanding when we think [Locke] |
| Full Idea: Ideas are whatsoever is the object of a man's understanding whenever a man thinks. | |
| From: John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 1.01.08) | |
| A reaction: Robinson quotes this to show how infuriatingly vague Locke is about ideas. Obviously they can be further analysed into a variety of mental events, ranging from inputs to reactions to judgements. |
| 15967 | The word 'idea' covers thinking best, for imaginings, concepts, and basic experiences [Locke] |
| Full Idea: Idea being that term which serves best to stand for the object of understanding when a man thinks, I use it to express what is meant by Phantasm, Notion, Species, or whatever it is, which the Mind can be employ'd about in thinking. | |
| From: John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 1.01.08), quoted by Peter Alexander - Ideas, Qualities and Corpuscles 04.1 | |
| A reaction: Compare my earlier Idea 6486, which caricatures Locke. Alexanders says Phantasms are uncaused mental images, Notions are concepts, and Species is an appearance of an object or quality to the mind. Locke deliberately covered them all. |
| 12496 | Complex ideas are all resolvable into simple ideas [Locke] |
| Full Idea: All our complex ideas are ultimately resolvable into simple ideas, of which they are compounded and originally made up. | |
| From: John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.22.09) | |
| A reaction: This can certainly be challenged. I guess we form the concept of a 'bird' before we form the concept of a 'feather'. How ideas are arrived at is quite different from ways in which they can be analysed and broken down. |
| 12938 | An idea is an independent inner object, which expresses the qualities of things [Leibniz] |
| Full Idea: An idea is an immediate inner object, which expresses the nature or qualities of things, ..but since it is the object of thought it can exist before and after the thoughts. | |
| From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.01) | |
| A reaction: This sounds something like Frege's 'third realm' between mind and world (Idea 7740). Notice that Leibniz is also using the word 'object' in this context. Leibniz doesn't make the mistake of confusing concepts and images, as many did. |
| 12945 | Thoughts correspond to sensations, but ideas are independent of thoughts [Leibniz] |
| Full Idea: I distinguish ideas from thoughts. For we always have all our pure or distinct ideas independently of the senses, but thoughts always correspond to some sensation. | |
| From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.01) | |
| A reaction: Leibniz's concept of an 'idea' is quite different from the empiricist notion of them, and strikes me as being much closer to Frege's notion of a concept. On the whole I like the Leibniz account best. |
| 19357 | The idea of green seems simple, but it must be compounded of the ideas of blue and yellow [Leibniz] |
| Full Idea: It is obvious that green comes from a mixture of blue and yellow; which makes it credible that the idea of green is composed of the ideas of those two colours, although the idea of green appears to us as simple as that of blue. | |
| From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.07) | |
| A reaction: This shows the use of 'idea' at that time for non-verbal mental events and concepts. Ideas are not, then, just undestood as phenomena, but can be analysed and explained more deeply. |
| 12950 | We must distinguish images from exact defined ideas [Leibniz] |
| Full Idea: It is essential to distinguish images from exact ideas which are composed of definitions. | |
| From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.09) | |
| A reaction: See Idea 12615, which is attacking Descartes and Locke, I think, but fails to register that Spinoza and Leibniz had got the notion of an 'idea' much more clearly. |
| 19427 | True ideas represent what is possible; false ideas represent contradictions [Leibniz] |
| Full Idea: An idea is true if what it represents is possible; false if the representation contains a contradiction. | |
| From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.287) | |
| A reaction: Odd in the analytic tradition to talk of a single idea or concept (rather than a proposition or utterance) as being 'true'. But there is clearly a notion of valid or legitimate or useful concepts here. Hilbert said true just meant non-contradictory. |
| 19423 | By an 'idea' I mean not an actual thought, but the resources we can draw on to think [Leibniz] |
| Full Idea: What I mean by an idea is not a certain act of thinking, but a power or faculty such that we have an idea of a thing even if we are not thinking about it but know that we can think it when the occasion arises. | |
| From: Gottfried Leibniz (What is an Idea? [1676], p.281) | |
| A reaction: 'Idea' tends to be used in the seventeenth century to mean an actual mental event. It is because Leibniz believes in the unconscious mind that he can offer this rather different, and probably superior, notion of an 'idea'. |
| 5374 | Berkeley probably used 'idea' to mean both the act of apprehension and the thing apprehended [Russell on Berkeley] |
| Full Idea: Berkeley seems to have confused the colour of the thing apprehended with the act of apprehension; probably either of these would have been called an 'idea' be Berkeley. | |
| From: comment on George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by Bertrand Russell - Problems of Philosophy | |
| A reaction: If we are saying that Berkeley's error was entirely verbal, there is a chicken-and-egg problem. He was an idealist, so he wouldn't have thought that there were two separate concepts behind the word 'idea'. Russell merely asserts that there are. |
| 23630 | Only philosophers treat ideas as objects [Reid] |
| Full Idea: The vulgar allow that an 'idea' implies a mind that thinks, an act of mind which we call thinking, and an object about which we think. But the philosopher conceives a fourth - the idea, which is the immediate object. …I believe this to be a mere fiction. | |
| From: Thomas Reid (Essays on Intellectual Powers 1: Preliminary [1785], 1) | |
| A reaction: Another example, to add to Yablo's list, of abstract objects invented by philosophers to fill holes in their theories. This one is illuminating, because we all say 'I've got an idea'. Cf discussions of the redundancy of truth. Cf propositions. |
| 12615 | Mental representations are the old 'Ideas', but without images [Fodor] |
| Full Idea: The idea that there are mental representations is the idea that there are Ideas minus the idea that Ideas are images. | |
| From: Jerry A. Fodor (Concepts:where cogn.science went wrong [1998], Ch.1) | |
| A reaction: Good for you, Fodor. I've always thought that the vociferous contempt with which modern philosphers refer to the old notion of 'Ideas' was grossly exaggerated. At last someone puts a clear finger on what seems to be the difficulty. |
| 5636 | Cartesian 'ideas' confuse concepts and propositions [Scruton] |
| Full Idea: Cartesian 'ideas' seem to be both concepts and propositions at once. | |
| From: Roger Scruton (Short History of Modern Philosophy [1981], Ch.4) | |
| A reaction: This seems to be the simple reason why modern philosophers don't like this seventeenth century notion. There is something slightly too tidy about the modern notion of propositions built out of concepts. Animals see propositions in a flash. |