That all mankind place their personality in something, which cannot be divided into two persons, or into halves or quarters of a person, is true; because the mind itself is indivisible, and the presence of this one indivisible mind is essential to personality. But, though essential to personality in man, mind is not all, in the popular sense of the word at least, which this comprehends. Thus, if, according to the system of metempsychosis, we were to suppose the mind, which animates any of our friends, to be the same mind, which animated Homer or Plato,--though we should have no scruple, in asserting the identity of the mind itself, in this corporeal transmigration,--there is no one, I conceive, who would think himself justifiable, in point of accuracy, in saying of Plato and his friend, that they were as exactly, in every respect, _the same person_, as if no _metempsychosis_ whatever had intervened. It does not follow from this, as Dr Reid very strangely supposes, that a leg or arm, if it had any relation to our personality, would, after amputation, be liable to a part of our engagements, or be entitled to a share of our merit or demerit; for the engagement, and the moral merit or demerit, belong not to the _body_, but to the _mind_, which we believe to continue precisely the same, after the amputation, as before it. This, however, is a question merely as to the comparative propriety of a term, and as such, therefore, it is unnecessary to dwell upon it. It is of much more importance, to proceed to the consideration of the actual identity of the mind, whether we term it simply _mental_ or _personal_ identity. “That there is something undoubtedly which _thinks_,” says Lord Shaftesbury, “our very doubt itself and scrupulous thought evinces. But in what subject that thought resides, and how _that_ subject is continued _one and the same_, so as to answer constantly to the supposed train of thoughts or reflections, which seem to run so harmoniously through a long course of life, with the same relation still to one single and self-same person, this is not a matter so easily or hastily decided, by those who are nice self-examiners, or searchers after truth and certainty.