Perception - What is a portrait? (Overlooking the lecture)

After having an hour lecture on the subject 'what is a portrait' i have found myself questioning the basics of myself and how we perceive ourselves. For example when taking a photo of myself how can i possibly potray me? What makes me me? Our personalities change and adapt over time just as our bodies do, with portraiture our subject is ever changing also. We are capturing them as they are in that specific time, how the photographer or subject wishes to be captured is their choice.
Maybe it's our thoughts, our consciousness that separates us from each other. If i were able to look into someones consciousness there would be no way to lie or hide from ones thoughts, i would know how they feel, their personal opinons. Do our memories make us who we are too? Looking back over old photos we reminisce, a sadness felt as it is only a memory. However how far back can we remember and how much do we make up? We fill the gaps instinctively to keep the memory alive.

Before we have anything in the world we have the ability to think, as we grow and learn thinking turns into judgement and opinon. Does this make us who we are?
When creating a portrait i understand that there are limitations, as in trying to portray someone for who they are and how they feel is one we can only attempt to do, as the photographer will never know how the subject is truly feeling.
Why do we have photos of family members, boyfriends/girlfriends, children, in our bags, wallets and purses? Its not like we take them out to admire them all the time, they just stay hidden until we occasionally glance at them. Is it a way to treasure a memory? If the photo was to become ripped or lost a feeling of sadness would overcome us as its a loss of something we intended of keeping for as long as possible. Maybe it's a way of keeping those close to us with us, on our busy day's. Knowing that their going on the same journey with you?
I found this lecture really interesting, i think as photographers unless we know the person well we can only attempt to capture the person how we have found them to be, our first impression of them. Yes the person i choose will end up becoming more of a friend than a stranger, but it's still my choice to portray them how i want them to be represented. We control the lighting, the focus, everything; it is our to choice to create a story to the viewer and have the viewer make judgement on the photo.

"I think therefore I am"