So far as English philosophy is concerned such theories appear to have had their origin in Locke’s teaching on person and personal identity. Discussing the notions of identity and diversity,(312) he distinguishes between the identity of an individual substance with itself in its duration throughout time, and what he terms personal identity; while by identity in general he means not abstract identity but the concrete permanence of a thing throughout time (34). On this we have to call attention to the fact that just as _duration_ is not essential to the _constitution_ of a substance, so neither is it essential to the constitution of a complete subsisting individual substance or person (64); though it is, of course, an essential condition for all human apprehension whether of substance or of person. Locke was wrong, therefore, in confounding what reveals to us the abiding permanence, identity or sameness of a subsisting thing or person (whether the “self” or any other subsisting thing or person) throughout its duration in time, with what constitutes the subsisting thing or person. Furthermore, his distinction between substantial identity, _i.e._ the sameness of an individual substance with itself throughout time, and personal identity or sameness, was also an error. For as long as there is _substantial_ unity, continuity, or identity of the subsisting individual substance, so long is there unity, continuity, or identity of its subsistence, or of its personality if it be a rational substance. The _subsistence_ of a complete individual inorganic substance is changed as soon as the individual undergoes _substantial_ change: we have them no longer _the same_ subsisting individual being. So, too, the subsistence of the organic individual is changed as soon as the latter undergoes _substantial_ change by the dissolution of life, by the separation of its formative and vital substantial principle from its material substantial principle: after such dissolution we have no longer _the same_ subsisting plant or animal. And, finally, the subsistence of an individual man is changed, or interrupted, or ceases by death, which separates his soul, his vital principle, from his body. We say, moreover, that in the latter case the human _person_ ceases to exist when the identity or permanence of his subsisting substance or nature terminates at death; for _personal identity_ we hold to be the identity of the complete subsisting substance or nature with itself. But Locke, who practically agrees with what we have said regarding the abiding identity of the subsisting individual being with itself—whether this individual be an inorganic individual, a plant, a brute beast, or a man(313)—distinguishes at this point between identity of the subsisting individual substance and _personal_ identity.