At the very moment of birth before we are ever first able to make use of the senses, we are subject to seemingly no ideas about the world, and definitely not any of the complex sort that make up abstract concepts like substance, causation, and identity, which have often been thought to be always innate in the human mind. Taking this argument a step further to rule out the possibility for innate ideas altogether, Locke then provides his own competing account for such notions, which according to him instead arise out of the composition of simple ideas generated by the experience of sensations over time. From a very young age we are always perceiving new things and reflecting inwardly on the relations between these experiences as to generate all of the most complex concepts which we hold to be central to the mind. In this way, the notion of identity necessitates a reflection on the persistence of simple ideas born out of the regularities of experience, where external objects impress themselves on to the senses their largely consistent sets of properties to be compared and contrasted against one another.
If a person were to be born instead in a pitch black cave, it is easy to see then how they would never come to possess our common understanding of identity, based at least in part on the observation of external things as we generally perceive them to be. They would never have any of these sort of experiences it would take in order to compose such a complex notion, due to their total lack of sensations only brought about by the external things which allow us to identify anything in the first place. Even worse for the Innatist, there are philosophical traditions throughout history which acknowledge the concept of identity as we today generally hold it to consist of, but deny for any kind of its existence altogether. As each of these sorts of abstract concepts, like identity, is then at best only acknowledged to widely varying extents, and never universally, it seems impossible for them to be born out of innate ideas. They could not suffer such extremely divisive opinions as those which tend to form around each attested innate concept of the mind, certainly not excluding that of identity. Although Locke desired first an alternative account to the innate concept of identity which would solve these sorts of problems, he thought it was a separate, further issue that we should be able to acknowledge specifically the identity of a thing persisting as the same kind across time, most notably being of the kind, “person”. While he is willing to allow that the nearly universal assent of certain ideas thought to be innate should necessitate his providing an alternative account of their propagation, he believes all prior notions concerning personal identity as an innate idea are rendered nonsensical in light of the uncompromising premises held by each polar extreme framing the ongoing controversy, which since antiquity has surrounded it.
Narrowed down to its most basic conception, the argument lies over whether personal identity is to be explained by either a physical or immaterial substance. According to Descartes’ Dualist tradition, we as thinking things are composed of an immaterial soul to which all the operations of the mind are necessarily constituents. This is as directly opposed to the physical body, which exhibits no form of thought at all, but is only acted upon through the processes of extension and its other modes. Locke claims otherwise that he does not feel thinking is not exactly essential to his personal identity, but that it is rather something he happens to do at certain times, most often when he is not asleep. More importantly, identity seems to at least be a concept which shares some relation with experience, so often basing our identifications on the similar sensations pressed on us between separate instances of it in time, but the soul comparably may only be posited and never itself observed. It seems impossible to found a theory of personal identity on the private soul when we will never come in contact with any other than our own, though we’d like to be able to account for the appearance of so many persons besides ourselves. In this way we seem to be moving toward a materialist view, which would identify oneself with their biological processes. However, Locke also wants to avoid diving in to any of the specific physical details in his own theory of personal identity, as he believes he will provide an ample account based on the workings of the understanding alone. Furthermore, this theory allegedly overcomes the difficulties still present for the physicalist today so many hundreds of years later, if they have not yet been found insurmountable, that consist primarily in identifying all the workings of the mind with their physical counterparts, as holding to a materialist view eventually necessitates.
Locke takes what he claims to be a deflationary stance toward personal identity among these two extremes. In this way he sets aside the metaphysical question concerning the ontological status of persons, claiming that we must first be able to deduce the practical limitations of the human condition before moving on to further philosophy. We should not trust our understanding subject to all these same very limitations to deduce convincing knowledge about matters which present themselves as being even less readily attainable to the mind. The apparent conditions for the continuity of life depend on the persistence of certain sets of biological processes as they function in organisms over time. In this way, a hawk is born from an egg, and eats food in order to sustain its digestive system, which provides nutrients to its other anatomical systems, including those which allow it to perceive the world around itself through the operation of its senses, and eventually these systems fail, at which point we would likely suggest that the hawk ceases to exist. What sets us apart again as persons from other living creatures is the continuing function of our self-conconsciousness through time, and so not only do we perceive the world around us, but we are able to look inward at this process and think about the things which we are perceiving, and are self-aware about the very fact that we are able to perceive at all.
For all the merits of this sort of alternative psychological process theory, which works to stake out a middle ground in the discussion of personal identity by setting aside the strong metaphysical question of existence for the more practical descriptive question of function, it seems to me to be too readily reducable to a physicalist theory. Ask any functionalist which takes up a theory similar to Locke’s whether they would assent to your shooting them in the skull. Locke is forced to bite the bullet and admit that personal identity is a separate issue from biological processes that make up a human, but that this does not disallow for the self-consciousness to be dependent on them. Although the sciences still have some ground to cover in the topics of biology and psychology, it does seem that they will eventually provide a complete description of the processes which we identify collectively as the self-conscious, and therefore an accurate theory of personal identity. But as long as the psychological view is yet preferable to any biological one for all the reasons so far presented, how can these two competing views be made compatible with what we hope to claim is an irreducably physical external world? In so far as there appears to be a yet insurmountable divide between the biological explanation of human life processes and the psychological explanation for their self-conscious, without positing any sort of redundant identity between these two separate physicalist projects, it seems that despite the strong basis which Locke set out and all the work which has been done since then, nearly the same question of personal identity still remains a topic of open debate.
Nativists believe that there is some amount of knowledge we as humans come equipped with as a basic part of our nature. This is a kind of knowledge that we do not gain through any sort of sensory experience, but instead have always held deep within our consciousness. It is also important in forming our apparent human rationality, rather than being deduced through its use as we generally might come about knowing say a novel mathematical proof. In fact, the nativist also claims that experience may at times some how bring such innate knowledge out from the depths of our subconscious, but even in such cases it was always lingering present within oneself, just lying dormant and waiting to be triggered. But how did it come about that we appear to possess innate knowledge in the first place? Some common explanations for the basis of such knowledge is that it has either been developed through the process of natural selection and is rooted in our genetics, or that it is instilled in us through some sort of higher power. However, we simply want to focus on what innate knowledge might be, or if we even possess it at all.
So if there is indeed such a thing, what preexisting knowledge do we come equipped with exactly? Of course nativists often differ as to the extent of such knowledge, but they all agree that there is some necessary minimum threshold in order for human nature to be as it is. Because many major nativists were doing their work at a time when the Catholic Church held a large amount of power, one very common belief is that the knowledge of the existence of God is innate. This very conveniently solves the common problem of faith, as all humans are born with the idea of God always present inside themselves, while still allowing for our imperfect will to falsely deny the existence of such inherent knowledge. Others believe that certain concepts of mathematics must be innate. In the subject of geometry we often speak very naturally about shapes like triangles and circles, and even without thinking about it particularly we appear to conceive of perfect forms of these shapes, but where do we draw these concepts from? It’s almost universally accepted that such shapes do not exist perfectly in nature, in that the closer we come to constructing a square, its imperfections merely become less and less apparent – but never nonexistent. Therefore such concepts can not be granted through any sort of sensory experience and then must be some how innate to human knowledge.
On the other hand, the empiricist claims that no knowledge is innate, and therefore that if we can hold any knowledge at all, as even this they at times oppose, it must somehow be gained through a process of sensory experience interactions. It would seem at first that the ability to acquire knowledge through the use of one’s reason alone leads to a quick contradiction, but the empiricist would reply that we may only use reason in order to generate relations between sets of information, not surprisingly gained through the use of sensory experience. Regardless, Locke doesn’t need to get in to this debate at all, as his sole objective is to simply deny the existence of innate knowledge. He suggests there are two ways in which knowledge can be innate, in the first it is simply knowledge that everybody possesses. But how can this be true considering even such a simple and universally agreed upon proposition as “a thing can not both be and not be” isn’t commonly accepted by say small children and the mentally handicapped? Children may even be able to lead their lives according to the principle, but not hold the exact concept so strongly in their mind. And surely their reason is still functioning to some extent, as they are without difficulty able to consider and express their basic needs. If on the other hand what is innate is our mere capacity to come to possess such knowledge, then what knowledge is there that is not innate, as are we not also capable of knowing everything that we happen to know? Although this isn’t necessarily a contradiction, Locke brushes it aside as being simply uninteresting: if all knowledge is inherently the same in our capacity to know it, there is then no reason to try to make a distinction between its being innate or not. Then it is either the case that innate knowledge is too narrow and there are perfectly rational beings that lead their lives without it, or too wide and all knowledge, no matter how large or small, is blandly equal in our capacity to know it.
Modern nativists will suggest it is neither inherent universal knowledge nor the capacity to know that represents innate knowledge, but rather that innate knowledge is something that is determined to crop up eventually as a normal part of human development. In this way it is simply the case that children have not yet reached the correct part of development in order for certain innate knowledge to present, and the handicapped have gone through abnormal development that prevents certain innate knowledge from presenting altogether. Let’s suggest that it is evolution which causes this and so something every human will tend to go through in a similar fashion. If the innate knowledge is acquired over time as we develop, and we can trust in this knowledge specifically because of its basis in evolution, is this still not ultimately knowledge based on experience – if even at some point in the distant past? It became useful for our species to tend to acquire certain knowledge because individuals who happened to acquire it were better off for it. Although it is true that some knowledge seems almost universal to be inevitably acquired, Locke presents a difficult case for the nativist to completely overcome in terms of explaining innate knowledge in a manner that warrants its distinction from knowledge developed strictly through sensory experience.