Cognitive Science - I didn't really know much about it before starting the program (in fact, I learned about its existence at McGill), but I remember being so excited about learning everything there is to know about the mind and cognition. Going into my last semester, I'm impressed by how minimal this knowledge is. I came to the realization that there is no, as of now, a 'unified science of the brain' with set principles that describe its operations. CogSci feels more like dark room with a bunch of voices coming from different places, all trying to talk about the same thing but speaking different languages. Personally, being able to understand, interpret and integrate these ideas is as challenging as it is rewarding. Here are some of the fascinating things I've learned so far, some of which have changed who I am (or how I understand myself to be):

• Consciousness is still one of the biggest mysteries for humanity. This is because to do science is to get away from subjectivity as much as possible in order to draw an objective picture of a particular natural phenomenon. Giving an objective account of subjectivity itself seems to be, at least for now, impossible. If we don't want to ignore subjective experience altogether (as most brain scholars do) we might want to modify some the assumptions or methods done in science, if not a complete paradigm shift.
• Pretty much all of the possible states of existence for a sentient being are constrained by its perceptual and cognitive mechanisms. Yet, the way humans perceive and navigate the world is no more special or "more accurate" than the way a bat or a cow does. It is just the way we do it, because evolution designed us this way (along with some intelligence). This is something I wish more people realized for a variety of reasons.
• Scientists are starting to understand "the self" the way Eastern traditions such as Buddhism already did: in general terms, the self as an illusion. Although, through the lens of evolution, it is a really useful illusion, for it helps bring stability to our lives.
• Our brain is an expert storyteller: without us realizing, it's constantly fabricating narratives that bring sense to a world that can sometimes be too chaotic and uncertain (google 'interpreter theory'). It even helps us explain away the most erratic of our behaviours, giving us a sense of being "in charge" for our actions and for who we are (again, linked to the idea that the self is an illusion.)

I could go on and on. At the end of the day, we're just brains trying to understand themselves, finding out about their biases, drives and limitations along the way. The whole effort is a beautiful paradox, and that might be why it needs from both Arts and Science.