3628. On this subject I have been instructed by much experience, and indeed that not only the things pertaining to the human mind, namely to its thought and affection, correspond to things spiritual and celestial which are of heaven from the Lord, but also the whole man in general, and in particular whatever is in man; insomuch that there is not the smallest part, nor even the smallest constituent of a part, which does not correspond; also that man exists and continually subsists therefrom; and further, that unless there were such a correspondence of man with heaven, and through heaven with the Lord, thus with what is prior to himself, and through prior things with the First, he would not subsist even a moment, but would dissolve into nothing.
 There are always two forces which, as before said, keep everything in its connection and in its form, namely, a force acting from without, and a force acting from within, in the midst of which forces is that which is kept in connection and form; thus is it with man as to every part of him, even the most minute. That the atmospheres are that which from without keep the whole body in connection, by their continual pressure or incumbence and the consequent acting force, is known; and also that the aerial atmosphere by its inflow keeps the lungs in their connection and form, and likewise its organ which is the ear, with its forms constructed therein according to the modifications of the air. It is also known that the ethereal atmosphere in like manner maintains the interior connections; for this atmosphere flows in freely through all the pores, and keeps the interior viscera of the whole body inseparable in their forms, by nearly the same pressure or incumbence, and the consequent acting force; also that the same atmosphere keeps in connection and form its organ which is the eye, with its forms therein constructed to the modifications of the ether. Unless there were internal forces correspondent to these which should react against the external forces and thus keep the intermediate forms in connection and equilibrium, they would not subsist a moment.
 From this it is evident that in order that anything may exist and subsist there must needs be two forces. The forces which flow in and act from within are from heaven and through heaven from the Lord, and have in themselves life. This is very clearly manifest from the organ of hearing: unless there were interior modifications, which are of life, and to which correspond the exterior modifications which are of the air, there would be no hearing. The same is also evident from the organ of sight: unless there were interior light which is of life, and to which corresponds the exterior light which is of the sun, no vision would be possible. The case is the same with all the other organs and members in the human body: there are forces acting from without, which are natural and in themselves not living, and there are forces acting from within, in themselves living, which keep every organ in its connection, and cause it to live, and this according to the form such as has been given them for use.