Introduction
At different stages of their lives, people can be very different. As time passes, their experience, knowledge about the outside world, reactions, and behaviors undergo numerous major changes. Moreover, as a result of the constantly occurring process of metabolism, all the individual atoms or molecules constituting a person’s body are eventually replaced over a certain period of time. On the contrary, some stable elements in an individual – such as the genotype, the obtained basic experience and knowledge about the world, and even the very perception of oneself as the same person – allow for speaking about the same person at different stages of their life, rather than about different people in different points of time.
Analysis
First of all, an individual retains their genotype throughout their life. However, certain mutations in their genes do occur due to various factors. Therefore, on the one hand, mutations of genes are possible. In addition, persons with identical genes (i.e., monovular twins) may demonstrate significantly different personal characteristics due to the varieties in the manifestations of their genotype in reaction to different environments (i.e., their phenotypes may differ considerably). On the other hand, the gene mutations are usually relatively minor, so the part of an individual which is defined by their genes will remain constant at all times, and the part which depends on the interaction between genes and external environment will still remain inside a certain array of possibilities dependent upon one’s genotype. The presence of this stable “core” and of a stable array of possibilities is one of the factors that permit an individual to remain at different stages in their life, even though some of their characteristics change.
Second, it is important that an individual retains the knowledge that they previously gained, and also learns new information each day. Therefore, the experience and knowledge accumulated throughout one’s life remain with that person and, in fact, have an effect not only on their attitudes and behaviors but also on what they will learn in the future. In contrast, new information and knowledge are continuously gained, and some of the old knowledge is constantly lost (forgotten). Again, the presence of a rather stable component allows for speaking of the same person at different stages of their life, even though new knowledge and skills gained every day may modify their attitudes and behaviors.
Finally, subjective factors, such as self-perception and memory, also play a critical role in ensuring that a person remains at different points of their life, even though their perceptions and memory change. On the one hand, a person forgets a considerable amount of details of their life (in particular, those which the brain does not “judge” to be important enough for preservation), and in certain cases, the memories of one’s past self mismatch one’s current conception of self. On the other hand, some memories of key points of one’s life still exist in all cases, and one will perceive these memories as one’s own memories, even if they find it difficult to “recognize themselves” in past situations. Therefore, people remember and perceive themselves as the same person throughout their lives, but at different stages of their life, an individual can be very different.
Conclusion
On the whole, although one can be very different at various stages of their life, they are still considered the same person rather than a number of distinct individuals. It is likely that this is because certain stable elements in a person (mainly “structural” components, such as the genotype; the basic, shaping experience of the world; and the perception of oneself as the same individual) allow for preserving a degree of stability of oneself and speak of oneself as of the same person, even though particular characteristics, traits, knowledge, and memories may differ considerably throughout one’s life.