Understanding what it means to be human and, more specifically, the nature of consciousness, has long occupied scientists and philosophers alike. We’ve seen consciousness explained as a connectome, a rainbow, and a kind of meaningful whole composed of meaningless parts. In this short video, philosopher John Searle defines consciousness by its four features — it’s real and irreducible, caused by brain processes, exists in the brain, and functions causably — and argues for a biological understanding that counters many of the philosophical conceptions. Perhaps a reductionist take — does the whole of our existence and purpose really amount to a set of biological processes? — but a fascinating one nonetheless.

We have to think of consciousness as a biological phenomenon. It’s as much a part of human and animal biology as digestion, or photosynthesis, or the secretion of bile, or mitosis… The main difference, at least in our present state of knowledge, is that we have a better understanding of digestion than we do of consciousness. The brain is a tough nut to crack.

For a deeper dive, see Searle’s fascinating Mind: A Brief Introduction.