That there is _some_ connection between the two is apparent from the very anxiety with which infidels have labored to undermine the doctrine of "spirit," on purpose to get rid of the doctrine of "immortality." But in stating the connection between them, we must exercise the utmost caution, lest we should unwarily place the truth on a precarious or questionable basis.

In arguing for the future life of the soul, as a doctrine of Natural Religion, some writers have spoken as if they supposed that nothing more was needful to demonstrate its "immortality" than the bare fact of its being "immaterial," and that, by its very nature as "spirit," it is indestructible by God Himself.

Now, we do not hold that the mere proof of its being an immaterial substance would necessarily infer its being also immortal.

For ought we know, the principle of life, sensation, memory, and volition _may_ belong to an immaterial substance even in the lower animals, who are not supposed to be immortal; and the only use which we would make of its "immateriality" in connection with its "immortality," is simply this,--that not being material, _its destruction is not necessarily implied in the dissolution of the body_.
It is not in the metaphysical doctrine of its immaterial nature, but in the practical evidence of its moral responsibilities and religious capacities, that we find the most satisfactory natural proof of its immortality.

It is perfectly possible to hold, on the one hand, that all "immaterial substances" are not necessarily indestructible; and yet to hold, on the other hand, that _such_ an immaterial substance as the soul of man is known to be,--endowed with conscience, with intelligence, with affections and aspirations, with hopes and fears such as can find no suitable object and no adequate range within the limits of the present life,--must be destined to an immortal existence.