What brings such changes about is the way in which emotional excitement alters. Things hot and vital to us to‐day are cold to‐morrow. It is as if seen from the hot parts of the field that the other parts appear to us, and from these hot parts personal desire and volition make their sallies. They are in short the centres of our dynamic energy, whereas the cold parts leave us indifferent and passive in proportion to their coldness. Whether such language be rigorously exact is for the present of no importance. It is exact enough, if you recognize from your own experience the facts which I seek to designate by it. Now there may be great oscillation in the emotional interest, and the hot places may shift before one almost as rapidly as the sparks that run through burnt‐up paper. Then we have the wavering and divided self we heard so much of in the previous lecture. Or the focus of excitement and heat, the point of view from which the aim is taken, may come to lie permanently within a certain system; and then, if the change be a religious one, we call it a _conversion_, especially if it be by crisis, or sudden. Let us hereafter, in speaking of the hot place in a man’s consciousness, the group of ideas to which he devotes himself, and from which he works, call it _the habitual centre of his personal energy_. It makes a great difference to a man whether one set of his ideas, or another, be the centre of his energy; and it makes a great difference, as regards any set of ideas which he may possess, whether they become central or remain peripheral in him. To say that a man is “converted” means, in these terms, that religious ideas, previously peripheral in his consciousness, now take a central place, and that religious aims form the habitual centre of his energy.