"The infant stretches his arm for the first time, by that volition without a known object, which is either a mere instinct or very near akin to one; this motion is accompanied with a certain feeling; he repeats the volition, which moves his arm, fifty or one thousand times, and the same progress of feeling takes place during the muscular action. In this repeated progress he feels the truth of that intuitive proposition, which in the whole course of the life that awaits him is to be the source of all his expectations, and the guide of all his actions--the simple proposition that _what has been_ as an antecedent, will be followed by _what has been_ as a consequent. At length he stretches out his arm _again_, and instead of the accustomed progression, there arises, in the resistance of some object opposed to him, a feeling of a very different kind, which, if he persevere in his voluntary effort, increases gradually to severe pain, before he has half completed the usual progress. There is a difference, therefore, which we may without any absurdity suppose to astonish the little reasoner; for the expectation of similar consequents from similar antecedents, is observable even in his earliest actions, and is probably the result of an original law of mind, as universal as that which renders certain sensations of sight and sound the immediate result of certain affections of our eye or ear. To any being who is thus impressed with belief of similarities of sequence, a different _consequent_ necessarily implies a difference of the _antecedent_. In the case at present supposed, however, the infant, who as yet knows nothing but himself, is conscious of no previous difference; and the feeling of _resistance_ seems to him, therefore, something _unknown_, which has its _cause in something that is not himself_."--(Vol. i. p. 514.)