| 1728 | Many objects of sensation are common to all the senses [Aristotle] |
| Full Idea: Common sense-objects are movement, rest, number, shape and size, which are not special to any one sense, but common to all. | |
| From: Aristotle (De Anima [c.329 BCE], 418a18) |
| 14037 | Atoms only have shape, weight and size, and the properties which accompany shape [Epicurus] |
| Full Idea: One must believe that the atoms bring with them none of the qualities of things which appear except shape, weight, and size and the properties which necessarily accompany shape. | |
| From: Epicurus (Letter to Herodotus [c.293 BCE], 54) | |
| A reaction: This appears to be fairly precisely a claim that atoms only have primary qualities, though that terminology only came in in the seventeenth century. I take the view to be more or less correct. |
| 16718 | Primary qualities are the cause of all the other sensible qualities [Albertus Magnus] |
| Full Idea: The primary qualities of tangible things are the cause of all the other sensible qualities. | |
| From: Albertus Magnus (On 'Generation and Corruption' [1261], II.1.1), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 21.2 | |
| A reaction: This makes the primary qualities sound suspiciously like the essence. |
| 16719 | The primary qualities are mixed to cause secondary qualities [Burley] |
| Full Idea: Secondary qualities are caused by a mixture of primary qualities. | |
| From: Walter Burley (De formis [1330], pars post p.65), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 21.2 | |
| A reaction: Like paint. He probably has in mind hot, cold, wet and dry as the primary qualities. |
| 6490 | For Descartes, objects have one primary quality, which is geometrical [Descartes, by Robinson,H] |
| Full Idea: Descartes denies any similarity between the physical world and ideas, as matter possesses only geometrical properties; Locke allows more primary qualities, but follows Boyle and the atomists in treating secondary qualities as creations of sense. | |
| From: report of René Descartes (Meditations [1641]) by Howard Robinson - Perception 1.5 | |
| A reaction: The interesting point to note here is that Descartes' geometrical view of objects (they are defined purely by 'extension') is the view that they have one minimal primary quality. I prefer Locke's view, of which the history (given here) is interesting. |
| 6725 | Locke believes matter is an inert, senseless substance, with extension, figure and motion [Locke, by Berkeley] |
| Full Idea: Some thinkers (e.g. Locke) understand by matter an inert, senseless substance, in which extension, figure and motion do actually subsist. | |
| From: report of John Locke (Essay Conc Human Understanding (2nd Ed) [1694]) by George Berkeley - The Principles of Human Knowledge §9 | |
| A reaction: Berkeley, of course, goes on to reject this. Personally I agree with Locke, because I am a realist, and I think the seventeenth century distinction between primary and secondary qualities is a key contribution to human understanding. |
| 15982 | Qualities are named as primary if they are needed for scientific explanation [Locke, by Alexander,P] |
| Full Idea: In Locke, the needs of scientific explanation are what determine which qualities are to be taken as primary. | |
| From: report of John Locke (Essay Conc Human Understanding (2nd Ed) [1694]) by Peter Alexander - Ideas, Qualities and Corpuscles 6 | |
| A reaction: Not a sharp distinction, but interesting. It must concern 'objective' explanations to cut out the secondary qualities. |
| 12479 | Primary qualities produce simple ideas, such as solidity, extension, motion and number [Locke] |
| Full Idea: The original or 'primary' qualities of body produce simple ideas in us, viz. solidity, extension, figure, motion or rest, and number. | |
| From: John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.08.09) | |
| A reaction: The tricky word here is 'simple', which clearly won't be enough on its own to distinguish primary from secondary qualities. Notice that there is a germ of an empirical theory of arithmetic in the word 'number'. |
| 12480 | Ideas of primary qualities resemble their objects, but those of secondary qualities don't [Locke] |
| Full Idea: The ideas of primary qualities of bodies are resemblances of them, and their pattern do really exist in the bodies themselves; but the ideas produced in us by secondary qualities have no resemblance to them at all. | |
| From: John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.08.15) | |
| A reaction: I think this is exactly right. More that one sense can reinforce a primary quality, because there is a 'pattern' to be detected in various ways. That things look square is explained by their squareness; things looking red is just very weird. |
| 7049 | In Locke, the primary qualities are also powers [Locke, by Heil] |
| Full Idea: Readers of Locke have been wrong to imagine that primary qualities are not themselves powers. | |
| From: report of John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.08.15) by John Heil - From an Ontological Point of View 17.2 | |
| A reaction: This is part of the move to connect Locke with modern essentialism about natural laws. If a disposition is a power, then clearly being hard or square will affect the dispositions, and hence be a power. Secondary qualities result from powers. |
| 3933 | Primary qualities (such as shape, solidity, mass) are held to really exist, unlike secondary qualities [Berkeley] |
| Full Idea: Sensible qualities are by philosophers divided into primary and secondary; the former are extension, figure, solidity, gravity, motion and rest, which exist really in bodies. | |
| From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.169) | |
| A reaction: A crucial distinction, which anti-realists such as Berkeley end up denying. I think it is a good distinction, and philosophers should fight to preserve it. |
| 23637 | Primary qualities are the object of mathematics [Reid] |
| Full Idea: The primary qualities are the object of the mathematical sciences. | |
| From: Thomas Reid (Essays on Intellectual Powers 2: Senses [1785], 17) | |
| A reaction: He spells out this crucial point, which is not so obvious in Locke. The sciences totally rely on the primary qualities, so it is ridiculous to reject the distinction (which Reid accepts). |
| 5466 | Primary qualities are number, figure, size, texture, motion, configuration, impenetrability and (?) mass [Ellis] |
| Full Idea: For Boyle, Locke and Newton, the qualities inherent in bodies were just the primary qualities, namely number, figure, size, texture, motion and configuration of parts, impenetrability and, perhaps, body (or mass). | |
| From: Brian Ellis (The Philosophy of Nature: new essentialism [2002], Ch.4) | |
| A reaction: It is nice to have a list. Ellis goes on to say these are too passive, and urges dispositions as primary. Even so, the original seventeenth century insight seems to me a brilliant step forward in our understanding of the world. |
| 22414 | You don't need to know how a square thing looks or feels to understand squareness [McGinn] |
| Full Idea: To grasp what it is for something to be square it is not constitutively necessary to know how square things look or feel, since what it is to be square does not involve any such relation to experience. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2) | |
| A reaction: You could even describe squareness verbally, unlike redness. It seems crucial that almost any sense (such as bat echoes) can communicate primary qualities, but secondary qualities are tied to a sense, and wouldn't exist without it. |
| 22423 | Touch doesn't provide direct experience of primary qualities, because touch feels temperature [McGinn] |
| Full Idea: Bennett's claim that touch provides experience of primary qualities without experience of any secondary qualities strikes me as false, because tactile experience includes felt temperature, which is a dispositional secondary quality. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: [J.Bennett 1971 pp. 90-4] Fair point. What about shape and texture? We experience forces, but the shape is assembled in imagination rather than in experience. So do we meet primary qualities directly in forces, such as acceleration? No secondary quality? |
| 22426 | We can perceive objectively, because primary qualities are not mind-created [McGinn] |
| Full Idea: I hold that experience succeeds in representing the world objectively, since primary quality perceptual content is not contributed by the mind. | |
| From: Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6) | |
| A reaction: My new example of a direct perception of a primary quality is acceleration in a lift. What would we say to one passenger who denied feeling the acceleration? It took an effort to see that mind contributes to secondary qualities (so make more effort?). |
| 3901 | Touch only seems to reveal primary qualities [Scruton] |
| Full Idea: Touch seems to deliver a purely primary-quality account of the world. | |
| From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 24) | |
| A reaction: Interesting, though a little over-confident. It seems occasionally possible for touch to be an illusion. |
| 6497 | We say objects possess no intrinsic secondary qualities because physicists don't need them [Robinson,H] |
| Full Idea: The idea that objects do not possess secondary qualities intrinsically rests on the thought that they do not figure in the physicist's account of the world; ..as they are causally idle, no purpose is served by attributing them to objects. | |
| From: Howard Robinson (Perception [1994], III.1) | |
| A reaction: On the whole I agree with this, but colours (for example) are not causally idle, as they seem to affect the behaviour of insects. They are properties which can only have a causal effect if there is a brain in their vicinity. Physicists ignore brains. |
| 7299 | Primary qualities can be described mathematically, unlike secondary qualities [Cardinal/Hayward/Jones] |
| Full Idea: All the primary qualities lend themselves readily to mathematical or geometric description. ...but it seems that secondary qualities are less amenable to being represented mathematically. | |
| From: Cardinal/Hayward/Jones (Epistemology [2004], Ch.4) | |
| A reaction: As a believer in the primary/secondary distinction, I welcome this point. This is either evidence for the external reality of primary qualities, or an interesting observation about maths. Do we make the primary/secondary distinction because we do maths? |
| 7300 | An object cannot remain an object without its primary qualities [Cardinal/Hayward/Jones] |
| Full Idea: An object cannot lack shape, size, position or motion and remain an object. | |
| From: Cardinal/Hayward/Jones (Epistemology [2004], Ch.4) | |
| A reaction: This points towards the essentialist view (see Idea 5453). This does raise the question of whether an object could lose its colour with impugnity, or the quality of sound that it makes when struck. |
| 19647 | The aspects of objects that can be mathematical allow it to have objective properties [Meillassoux] |
| Full Idea: All aspects of the object that can give rise to a mathematical thought rather than to a perception or a sensation can be meaningfully turned into the properties of the thing not only as it is with me, but also as it is without me. | |
| From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 1) | |
| A reaction: This is Meillassoux's spin on the primary/secondary distinction, which he places at the heart of the scientific revolution. Cartesian dualism offers a separate space for the secondary qualities. He is appalled when philosophers reject the distinction. |