I

What defines who I am?

Upon quick questioning, it doesn't seem too difficult to know what makes anyone that person. Perhaps, the general idea that someone is their physical body. With deeper digging, questions can arise to challenge the details of this idea. Who I am, or anyone is, in general, would basically come down to what the common interpretation is, of using that term. Different people could have different perspectives of what applies to define who someone is, but I’ll try to cover what seems to be the most common interpretations, and go into detail of potential rational parameters.

If it’s their physical body, at what point of the body's composition changing, does that change who the person is? According to studies, every cell in the human body is replaced by a new cell, over a 7-10 yr span. Does that make it a new person every 7yrs? Is it still the same person if they become brain dead, or lose all memories? Is a dead body of mostly the same composition, still the same person? If someone’s consciousness (or entire function of brain and memories) is transferred into another person or computer, is that still them?

It seems, at least by what most would likely perceive after considering the details, that a physical body does not effectively define who I am. Since the physical composition changes constantly, and the body could even be discluded (if the mind was transferred) from some perspectives. Perhaps the mind should be included, at least partially. But even if the mind defines who I am, some aspect of the body could likely still be included, since the mind functions based on the body it has used to build its methods of function in experience.

The mind has similar problems to the body as a definition, considering it changes constantly, from every experience that someone goes through. Every experience adds new memories and new neurochemical reinforcement (as further described in a post from 7 months ago; Reinforcement Mechanisms). From new reinforcement, changes likely occur at least to a slight degree, in habits, preferences, and ideologies. 

So it seems neither 100% body composition, or 100% mind composition effectively define who I am. Those ideas could potentially define who I am at 1 given moment, but it would change constantly with time. It seems that common interpretation would be that what defines someone would include a relevant time span. During a time span, perhaps someone can be considered to be; how their mind and body functioned throughout that timespan. 

Which timespan is relevant for defining someone, is likely a broadly changing variable, depending on perspective. A lot of people might consider somebody to be how they functioned throughout their entire life, whereas a lot of perspectives might be that someone is a different person after significant changes in their functions. Perhaps it can be generalized and categorized into 2 types of what defines someone; 1) Someone’s mind’s reactions (which incorporates their body) over their entire life. Or 2) over a period of time, before significant change (which in itself would have to be determined based on particular circumstances) in reactions.

It seems that the mind is likely more significant in defining who someone is, since it is what controls the body, and it is commonly the factor more significantly involved in someone’s reactions, interactions, influences, and decisions through life. But the physical body could still be a factor included, since the function of the mind is based on experience of utilizing that body. The tendencies of the mind over a timespan, seem to be a more applicable outline, than the mind at any given moment, but the length of time seems to be a significant variable based on perspective. Overall, it seems to be my mind that defines the answer to; who am I?