‘This strong combination of ideas, not allied by nature, the mind makes in itself either voluntarily or by chance: and hence it comes in different men to be very different, according to their different inclinations, educations, interests, &c. Custom settles habits of thinking in the understanding, as well as of determining in the will, and of motions in the body: all which seems to be but trains of motion in the animal spirits, which once set agoing continue in the same steps they have been used to, which by often treading are worn into a smooth path, and the motion in it becomes easy, and as it were natural. As far as we can comprehend thinking, thus ideas seem to be produced in our minds; or if they are not, this may serve to explain their following one another in an habitual train when once they are put into that track, as well as it does to explain such motions of the body. A musician used to any tune will find, that let it but once begin in his head, the ideas of the several notes of it will follow one another orderly in his understanding, without any care or attention, as regularly as his finger moves orderly over the keys of the organ to play out the tune he has begun, though his inattentive thoughts be elsewhere a wandering. Whether the natural cause of these ideas, as well as of that regular dancing of the fingers, be the motion of his animal spirits, I will not determine, how probable soever by this instance it appears to be so; but this may help us a little to conceive of intellectual habits, and of the tying together of ideas. That there are such associations of them made by custom in the minds of most men, I think nobody will question, who has well considered himself or others; and to this perhaps might be justly attributed most of the sympathies and antipathies observable in men, which work as strongly and produce as regular effects as if they were natural, and are therefore called so, though they at first had no other original but the accidental connexion of two ideas, which either the strength of the first impression or future indulgence so united, that they always afterwards kept company together in that man’s mind, as if they were but one idea. I say, most of the antipathies, I do not say all; for some of them are truly natural, depend upon our original constitution, and are born with us; but a great part of those which are counted natural, would have been known to be from unheeded though perhaps early impressions, or wanton fancies at first, which would have been acknowledged the original of them, if they had been warily observed.’ The former part of this passage, relating to the dancing of the animal spirits, the Abbé Condillac in his ‘Logic’ has paraphrased with a self-sufficiency, an assumption of originality, and a smoothness of flippancy, peculiar almost to himself.