KNOWLEDGE softness, and such other qualities, as we discern by feeling All which qualities called sensible, are in the object that causeth them, but so many several motions of the matter, by which it presseth our organs diversely (L, 9) The account of sensation in the empiricist Hobbes turns out to be exactly the same as that of the rationalist Descartes For both of them, qualities such as colour and taste are nothing more than deceptive experiences, items of private consciousness: ‘fancies’ for Hobbes; ‘cogitationes’ for Descartes Hobbes uses arguments similar to those of Descartes to urge the subjectivity of such secondary qualities: we see colours in reXections; a bang upon the eye makes us see stars; and so on For Hobbes as for Descartes, there is no intrinsic diVerence between our sensory experience and our mental imagery and our dreams Just as Descartes argued that he could be certain of the content of his thoughts even if he had no body and there was no external world, so Hobbes argues that all our images would remain the same even though the world were annihilated (L, 22) A common error underlies the Descartes–Hobbes attack on the objectivity of sensory qualities: a confusion between relativity and subjectivity It is true that sensory qualities are relative; that is to say, they are deWned by their relationships to sensory perceivers For a substance to have a certain taste is for it to have the ability to produce a certain eVect on a human being or other animal; and the particular eVect it produces will vary according to a number of conditions But the fact that taste is a relative property does not mean that it is not an objective property ‘Being larger than the earth’ is a relative property; yet it is an objective fact that the sun is larger than the earth Where Hobbes diVers from Descartes is that he fails to make any serious distinction between the imagination and the intellect If the intellect is, roughly, the capacity to use and understand language, then it is something quite diVerent from the Xow of images in the mind Descartes made clear the diVerence between intellect and imagination in a luminous passage of the sixth Meditation: When I imagine a triangle, I not just understand that it is a Wgure enclosed in three lines; I also at the same time see the three lines present before my mind’s eye, and this is what I call imagining them Now if I want to think of a chiliagon, I understand just as well that it is a Wgure of a thousand sides as I that a triangle is a Wgure of three sides; but I not in the same way imagine the thousand sides, or see them as presented to me (AT VII.71; CSMK II 50) 130