KNOWLEDGE very Wne powder, it will lose this quality without ceasing to be a body Again, we reject colour: we have often seen stones so transparent as to be colourless What are we to make of such arguments? It may be true that a body must have some shape or other, but any particular shape can be lost As Descartes himself reminds us elsewhere, a piece of wax may cease to be cubical and become spherical What Locke says of the secondary qualities might also be said of some of the primary qualities Motion is a primary quality, but a body may be motionless Indeed, if motion and rest are to be considered, as Locke considers them, as a pair of primary qualities, at any time a body must lack one or other of them The argument for the permanence of primary properties seems to depend on taking them generically: a body cannot cease to have some length or other; some breadth or other; some height or other The argument for the impermanence of other qualities seems to depend on taking them speciWcally: a body may lose its particular colour or smell or taste It is true that a body may be tasteless, odourless, and invisible, whereas a body cannot lack all extension But the fact that such qualities are inessential properties of bodies does not show that they are not genuine properties of bodies, any more than the fact that a body may cease to be cubical shows that a cubical shape, while it lasts, is not a genuine property of the body Locke says that secondary qualities are nothing but a power to produce sensations in us Even if we grant that this is true, or at least an approximation to the truth, it does not show that secondary qualities are merely subjective rather than being genuine properties of the objects that appear to possess them To take a parallel case, to be poisonous is simply to have a power to produce a certain eVect in a living being; but it is an objective matter, a matter of ascertainable fact, whether something is or is not poisonous to a given organism Here, as in Descartes and Hobbes, we meet a confusion between relativity and subjectivity A property can be relative while being perfectly objective Whether a key Wts a lock is a plain matter of fact, and as Locke’s contemporary Robert Boyle remarked, the secondary qualities are keys which Wt particular locks, the locks being the diVerent human senses ‘The particular Bulk, Number, Figure, and Motion of the parts of Fire, or Snow, are really in them,’ Locke says, ‘whether any ones senses perceive 135