perfect in these rudiments of walking, the view of a favourite plaything will excite various motions in the limbs; and thus if he be set upon his legs, and his body carried forward by the nurse, an imperfect attempt to walk follows of course. It is made more perfect gradually by his improvements in the rudiments, by the nurse’s moving his legs alternately in the proper manner, by his desire of going up to persons, playthings, &c. and thence repeating the process which has succeeded (for he makes innumerable trials, both successful and unsuccessful;) and by his seeing others walk, and endeavouring to imitate them.
It deserves notice here, that in the limbs, where the motions are most perfectly voluntary, all the muscles have antagonists, and often such as are of nearly equal strength with themselves; also, that the muscles of the limbs are not much influenced at first by common impressions made on the skin, and scarce at all when the child is so far advanced as to get a voluntary power over them. For these things facilitate the generation of the voluntary power, by making the muscles of the limbs chiefly dependent on the vibrations which descend from the brain, and also disposing them to act from a small balance in favour of this or that set of antagonists.
When the child can walk up to an object that he desires to walk up to, the action may be termed voluntary, i.e. the use of language will then justify this appellation. But it appears from the reasoning here used, that this kind and degree of voluntary power over his motions is generated by proper combinations and associations of the automatic motions, agreeably to the corollaries of the twentieth proposition. Voluntary powers may therefore result from association, as is asserted in these papers.
When he is arrived at such a perfection in walking, as to walk readily upon being desired by another person, the action is esteemed still more voluntary. One reason of which is, that the child, in some cases, does not walk when desired, whilst yet the circumstances are apparently the same as when he does. For here the unapparent cause of walking, or not walking, is will. However, it follows from this theory, that all this is still owing to association, or to something equally suitable to the foregoing theory; e.g. to the then present strength or weakness of the association of the words of the command with the action of walking, to its proceeding from this or that person, in this or that manner, to the child’s being in an active or inactive state, attentive or inattentive, disposed by other circumstances to move as directed, or to move in a different way, &c. a careful observation of the fact will always shew, as far as is reasonably to be expected in so nice a matter, that when children do different things, the real circumstances, natural or associated, are proportionably different, and that the state of mind called will depends upon this difference. This degree of
