Thomas Reid makes a number of objections to Locke’s views on personal identity. As we have seen, according to Locke, personal identity depends entirely on memory, or what he calls "consciousness" of past actions. In this paper, I shall outline only one of Reid’s objections, that is, that Locke confuses personal identity "with the evidence we have of our personal identity" (p. 115 last two lines), and speculate on what Locke would say to this objection.

Reid attacks Locke, saying that there is a difference between what actually constitutes personal identity and what allows us to recognize personal identity. Moreover, he makes the claim that it is an "absurdity too gross to be entertained"(p, 116 line 7) to think that these can be one and the same; for it is not just that Locke makes an unfounded leap from the evidence of identity to identity itself, but that one cannot say that memory, which allows us to recognize something, can cause the thing it is pointing to to exist. In other words, according to Reid, Locke is saying that memory at once is evidence of personhood, and at the same time causes personhood.

Reid uses the example of a man who has a horse stolen. The only way to identify a horse as the stolen horse, says Reid, is by identifying its properties and noting that they are exactly similar to those of the horse in question. However, this similarity is not what constitutes the horse’s identity. Similarly, the only way of identifiying myself as the same person as yesterday is that I remember my actions and thoughts. However, Reid argues that if this means that my memory constitutes myself, it would follow that the horses similar features to itself constitute its identity.

Locke could answer this objection on a number of levels. First, he could say that it is not unusual for evidence of something to be the same as that something. For example, assume we want to determine whether something is or is not red. The evidence of its redness is its redness. We see that something is red, and supposing we are not color blind, the experience of redness means the object is red.

Second, Reid says that Locke is making it that "the testimony is the cause of the thing being testified." (p. 116 lines 12-13) But Locke could say that this is not really a problem. I don’t know whether my experience of seeing something as red causes it to be red, but there are cases where there is this type causation. Take, for instance, the experience of boredom. My feelings of boredom or experience of boredom are at once evidence of my boredom, causes of my being bored, and finally, constitute my boredom!

Fnally, Locke could say that the horse example first does not apply to personal identity, and second, that it is not sufficient for supporting Reid’s own claims. When it comes to determinig identity of things or persons outside the self, Locke explicitly differentiates between evidence and reality when he writes about the drunk man. In that case, evidence points to a sober man having committed a certain crime while drunk. Although the sober man is exactly similar to the drunk man, Locke explicitly says that evidence does not suffice to identify the person, and that in fact they are not the same person. So clearly the similarity of the horse does not for Locke constitute its identity.

Furthermore, the example of the horse in no way proves Reid’s claim that evidence cannot constitute identity. Instead, Locke could point out that this example only shows that the identity of the horse does not consist "solely in similitude." It does not follow that personal identity cannot consist solely in memory. In other words, Locke could argue that just because in the horse’s case more than one factor contributes to its identity, it does not necessaritly apply to a case where only one thing constitutes identity, as in memory in the case of personal identity. In other words, when something has one essential defining characteristic, it is only that characteristic which can supply evidence for its existence. Personal identity is such a case, even if "horse identity" isn’t.

In conclusion, these responses more than adequately respond to Reid’s objection, primarily because it is not such an obvious absurdity to equate evidence with its object, and subsequently because I don’t think Locke actually confuses these two things. In fact, he would openly admit that memory at once provides evidence for personal identity, and by that very fact constitutes personal identity, for without this sort of evidence, personal identity as we know it would not exist. In other words, personal identity for Locke consists in nothing else than the fact that we have this sort of evidence for it.