That is to say, my object is not a thought. But sensuous perception and recollection are thought, and thought is truth.[220] Locke, however, places the reality of the understanding only in the formal activity of constituting new determinations from the simple conceptions received by means of perception, through their comparison and the combination of several into one; it is the apprehension of the abstract sensations which are contained in the objects. Locke likewise distinguishes (Bk. II. chap. xi. § 15-17) between pure and mixed modes. Pure modes are simple determinations such as power, number, infinitude; in such expressions as causality we reach, on the other hand, a mixed mode. Locke now explains in detail the manner in which the mind, from the simple ideas of experience, reaches more complex ideas; but this derivation of general determinations from concrete perception is most unmeaning, trivial, tiresome and diffuse; it is entirely formal, an empty tautology. For instance we form the general conception of space from the perception of the distance of bodies by means of sight and feeling.[221] Or in other words, we perceive a definite space, abstract from it, and then we have the conception of space generally; the perception of distances gives us conceptions of space. This however is no deduction, but only a setting aside of other determinations; since distance itself is really space, mind thus determines space from space. Similarly we reach the notion of time through the unbroken succession of conceptions during our waking moments,[222] _i.e._ from determinate time we perceive time in general. Conceptions follow one another in a continual succession; if we set aside the particular element that is present we thereby receive the conception of time. Substance (which Locke does not accept in so lofty a sense as Spinoza), a complex idea, hence arises from the fact that we often perceive simple ideas such as blue, heavy, etc., in association with one another. This association we represent to ourselves as something which so to speak supports these simple ideas, or in which they exist.[223] Locke likewise deduces the general conception of power.[224] The determinations of freedom and necessity, cause and effect, are then derived in a similar way. “In the notice that our senses take of the constant vicissitude of things, we cannot but observe, that several particulars, both qualities and substance, begin to exist; and that they receive this their existence from the due application and operation of some other being. From this observation we get our ideas of cause and effect,” for instance when wax is melted by the fire.[225] Locke goes on to say: “Every one, I think, finds in himself a power to begin or forbear, continue or put an end to several actions in himself. From the consideration of the extent of this power of the mind over the actions of the man, which every one finds in himself, arise the ideas of liberty and necessity.”[226]