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Single Idea 22414

[filed under theme 12. Knowledge Sources / B. Perception / 2. Qualities in Perception / c. Primary qualities ]

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.

Gist of Idea

You don't need to know how a square thing looks or feels to understand squareness

Source

Colin McGinn (Subjective View: sec qualities and indexicals [1983], 2)

Book Ref

McGinn,Colin: 'The Subjective View' [OUP 1983], p.8

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.

Related Idea

Idea 22413 Being red simply consists in looking red [McGinn]

The 21 ideas with the same theme [qualities considered independent of observation]:

1728 Many objects of sensation are common to all the senses [Aristotle]
14037 Atoms only have shape, weight and size, and the properties which accompany shape [Epicurus]
16718 Primary qualities are the cause of all the other sensible qualities [Albertus Magnus]
16719 The primary qualities are mixed to cause secondary qualities [Burley]
6490 For Descartes, objects have one primary quality, which is geometrical [Descartes, by Robinson,H]
6725 Locke believes matter is an inert, senseless substance, with extension, figure and motion [Locke, by Berkeley]
15982 Qualities are named as primary if they are needed for scientific explanation [Locke, by Alexander,P]
12479 Primary qualities produce simple ideas, such as solidity, extension, motion and number [Locke]
12480 Ideas of primary qualities resemble their objects, but those of secondary qualities don't [Locke]
7049 In Locke, the primary qualities are also powers [Locke, by Heil]
3933 Primary qualities (such as shape, solidity, mass) are held to really exist, unlike secondary qualities [Berkeley]
23637 Primary qualities are the object of mathematics [Reid]
5466 Primary qualities are number, figure, size, texture, motion, configuration, impenetrability and (?) mass [Ellis]
22414 You don't need to know how a square thing looks or feels to understand squareness [McGinn]
22423 Touch doesn't provide direct experience of primary qualities, because touch feels temperature [McGinn]
22426 We can perceive objectively, because primary qualities are not mind-created [McGinn]
3901 Touch only seems to reveal primary qualities [Scruton]
6497 We say objects possess no intrinsic secondary qualities because physicists don't need them [Robinson,H]
7299 Primary qualities can be described mathematically, unlike secondary qualities [Cardinal/Hayward/Jones]
7300 An object cannot remain an object without its primary qualities [Cardinal/Hayward/Jones]
19647 The aspects of objects that can be mathematical allow it to have objective properties [Meillassoux]