Deacon:
My understanding is that people are the most complex of the creatures we see around us today, mostly because of our brain.
I believe humans developed from simpler life forms over time. As I am not religious, I don’t have the option of saying that we have a soul. I think we have a brain.
I don’t think we can conclude that certain parts of the human body could only have been “designed” by a creator. The eye for instance exists in a variety of executions in nature—everything from simple light-sensitive cells, via eyes that resemble primitive box cameras (squid), to the amazingly acute eyes of a falcon or a vulture, to the middling human eye (not very good at one thing, pretty good at most things), has evolved from simpler types over the course of natural history.
Best,
Tor