The brain is very, very complex. There are 100,000,000,000 neurons, with each one being connected to 10,000 others, and all the connections can be strengthened and weakened. Some people have called it the most complex object in the known Universe, and this is not much of an exaggeration.
The pattern of connections matters – it is what makes us feel emotion, think, see, hear, understand, remember and so on. We don’t really understand how it works and this is what makes it so fascinating. Everything that makes our existence seem meaningful comes from the brain.