78. On the other hand, an exceedingly simple explication of the method in which abstraction is made, may be opposed to this argument apparently so conclusive. We see the paper upon which we write; this sensation involves two things, whiteness and extension. Were we limited to simple sensation, here we should stop, and receive only the impression, extension and whiteness. But having within ourselves a faculty distinct from that of feeling, which makes us capable of reflecting upon the very sensation we experience, we can consider that this sensation has some similarity to others which we recollect to have experienced. We can then consider extension and whiteness in themselves, abstracting the actual affection which they produce in us. Afterwards we can reflect upon the fact that these sensations have something in common with others, inasmuch as they all affect us in a certain manner, and then we have the idea of sensation in general. If, then, we consider that these sensations all have something in common with all that is in us, in so far as they modify us in a certain manner, we shall form an idea of a modification of the _me_, making abstraction, however, of its being a sensation, a thought, or an act of the will; and if, finally, we abstract from these things being in us, their being substances or modifications, and attend only to the fact that they are something, we shall have attained the idea of being. This idea may, therefore, be formed by abstraction. This explication, seductive as it is by reason of its simplicity, is open to grave objections. 79. From the very beginning of this process we make use, without adverting to it, of the idea of being; we therefore deceive ourselves when we imagine that we form it. We cannot reflect upon extension and whiteness without remarking that they exist, that they are _something_ similar to other sensations. When we think upon what affects us, we know that _we are_, that that which affects us _is_, and we speak of its being or not being, of its having or not having _something common_; and finally, when we abstract the modifications of our mind as being this or that, and regard them only as _thing_, as _something_, as a _being_, we evidently cannot so consider them if there does not exist in us the idea of _something_ in general, that is, of being. Thus being is a predicate which we apply to things; we do, therefore, know this predicate. We only collect in one general and indeterminate idea, particular and determinate things, already existing in our understanding. The successive operations made by means of abstraction are only a decomposition of the object, a classification of it in various general ideas so as to attain to the superior idea of being.