634. But it is extremely difficult to say, in a manner to be apprehended, what is the understanding of truth and the will of good in the proper sense, for the reason that a man supposes everything he thinks to be of the understanding, since he calls it so; and everything that he desires he supposes to be of the will, since he calls it so. And it is the more difficult to explain this so as to be apprehended, because most men at this day are also ignorant of the fact that what is of the understanding is distinct from what is of the will, for when they think anything they say they will it, and when they will a thing they say they think it. This is one cause of the difficulty, and another reason why this subject can with difficulty be comprehended is that men are solely in what is of the body, that is, their life is in the most external things.  And for these reasons they do not know that there is in every man something that is interior, and something still interior to that, and indeed an inmost; and that his corporeal and sensuous part is only the outermost. Desires, and things of the memory, are interior; affections and rational things are interior still to these; and the will of good and understanding of truth are inmost. And these are so distinct from each other that nothing can ever be more distinct. The corporeal man makes all these into a one, and confounds them. This is why he believes that when his body dies all things are to die; though in fact he then first begins to live, and this by his interiors following one another closely in their order. If his interiors were not thus distinct, and did not thus succeed each other, men could never be in the other life spirits, angelic spirits, and angels, who are thus distinguished according to their interiors. For this reason there are three heavens, most distinct from each other. From these considerations it may now in some measure be evident what, in the proper sense, are the understanding of truth and the will of good; and that they can be predicated only of the celestial man, or of the angels of the third heaven.