Till, tir'd, he sleeps,—and life's poor play is o'er.”[48]
The supposed test of identity, when applied to the mind in these cases, completely fails. It neither affects, nor is affected, in the same manner, in the same circumstances. It, therefore, if the test be a just one, is not the same identical mind.
This argument against the identity of the mind, drawn from the occasional striking contrasts of character in the same individual at different periods of life, or when, by great changes of fortune, he may have been placed suddenly in circumstances remarkably different, must, in some degree, have forced itself upon every one who has been at all accustomed to reflect; and yet, in no one instance, I may safely say, can it have produced conviction even for a moment. I have stated it to you, without attempting to lessen its force by any allusion to the fallacy on which it is founded; because the nature of this fallacy is afterwards to be fully considered by us.
There is another argument that may be urged against the identity of the sentient and thinking principle, which has at least equal semblance of force, though it does not occur so readily, because it does not proceed on those general and lasting changes of character with which every one must be struck, but on the passing phenomena of the moment, which are not inconsistent with a continuance of the same general character, and which, as common to all mankind, and forming, indeed, the whole customary and familiar series of our thoughts and emotions, excite no astonishment when we look back on them in the order of their succession.
The mere diversity of our feelings at different moments, it may be said, is of itself incompatible with the strict and absolute unity which is supposed to belong to the thinking principle. If joy and sorrow, such as every one has felt, be different, that which is joyful, and that which is sorrowful, cannot be precisely the same. On the supposition of complete unity and permanence of the thinking principle, nothing is added to it, nothing is taken away from it; and, as it has no parts, no internal change of elementary composition can take place in it. But that to which nothing is added, from which nothing is taken away, and which has no parts to vary their own relative positions and affinities, is so strictly the same, it may be said, that it would surely be absurd to predicate of it any diversity whatever. Joy and sorrow imply an unquestionable diversity of some kind; and if this diversity cannot be predicated of that substance which is precisely the same, without addition, subtraction, or any internal change of composition whatever, that which is joyful, and that which is sorrowful, cannot have absolute identity; or if we affirm, that a diversity, so striking as to form an absolute contrast, is yet not inconsistent with complete and permanent unity and identity, we may, in like manner, affirm, that a substance which is hard, heavy, blue, transparent,—which unites with acids, not, with alkalies,—and which is volatilizable at a low temperature,—is precisely the same substance as that, which is soft, light, green, opaque,—which unites with alkalies, not with acids,—and which is absolutely infusible and fixed in the highest temperature to which we can expose it.
I have thus endeavoured to place, in the strongest possible light, the most imposing arguments which I can conceive to be urged against the permanent identity of the sentient and thinking principle, that, in combating even Sophistry itself, you may learn, as I have said, to combat with it on equal ground, and assume no advantage but that irresistible advantage which Truth must always afford to him who is the combatant of Error.
The positive evidence of the identity of the mind I shall proceed to consider in my next Lecture.
Footnotes
[44] Mart. Scrib. chap. vii.—Pope's Works, edit. 1757, v. vii. p. 82–84.
[45] Essays on the Intellectual Powers, Essay III. chap. iv.—v. 1. p. 341. Edit. Ed. 1808.