The New York Times yesterday ran a bunch of articles about molecular biology, evolution, and evo-devo. All of which are awesome subjects and you should read about. One of them in particular was interesting, because it was about the idea of the soul and its place in biology/science. That article can be found here. The point of the article in the New York Times is basically two-fold, and obvious.
First off, the idea of the soul isn't biological in nature and therefore the question isn't a scientific one to begin with -- if you want to believe that humans have souls, you will, regardless of any scientific fact or lack thereof. And if you don't want to believe in the soul, you won't, regardless of any scientific fact or lack thereof. Pretty much every scientist in the article says this, which is perfectly logical and somewhat obvious.
The second idea, however, is the one that interests me. It is based on the presumption (which may be a rather large one, and I would have no idea since I am so very much not an expert on religion or the idea of the soul) that the soul and the capacity for complex thought and reason are the same thing. Or rather, that while the soul itself is by nature a religious/spiritual thing and cannot be guaged by science, conciousness or the capacity to reason is not, and perhaps a physical manifestation thereof can be found. Hence, conciousness is science's soul - the closest thing to a soul that can be guaged scientifically.
The interesting thing is that neurologists and their ilk are increasingly able to isolate the physical manifestations of things like conciousness, aesthetics, sensory perception, and the like. (For a GREAT review of this with a wry wit and a thoroughly readable voice, I recommend V.S. Ramachandran -- who is unfortunately not the same Ramachandran of Ramachandran plot fame.) AND other mammals, like mice, and other vertebrates, like fish and birds, seem to have similar or analogous structures in their brains.
An example is an article in Nature this week. (Here it is for those of you who can get it because you have access to a university's subscription or something like that. If you would like me to e-mail you the pdf, feel free to send me an e-mail.)
Some background: (Ramachandran covers this very briefly in one of his books). The Lateral Intraparietal area (LIP) appears to accumulate visual cues to make a decision in humans. These decisions are often probabilistic -- i.e. there is no specific predetermined right or wrong answer, but merely a bias toward reward with one specific outcome. These people trained monkeys to be able to make such a probabilistic choice. They would see four shapes on a screen and then look towards a red dot or a green dot. Depending on which dot the monkeys looked at, they would be rewarded, and the correct dot was determined in a probabilistic manner based on the shapes that were shown. (Each of the 10 shapes had a weight, changing the probability by -infinity, -.9, -.7, -.5, -.3, .3, .5, .7, .9, and infinity respectively).
The researchers saw a few interesting things: first, the monkeys were trainable but different monkeys picked up the patterns to greater or lesser extents. Second, the choice the monkeys made appeared to be strongly related to the activity in the LIP when the choice was made. Finally, the activity in the LIP was proportional (roughly) to a log likelihood ratio that the red dot was correct based on the shapes shown.
The big selling point, for me, is that these monkeys were guessing. What's more, they weren't guessing at random, but rather they were figuring out a pattern and guessing in an educated way. They seem to have been using logic to make an educated guess. That's a very human action, not an instinctual action. I've had arguments before about will vs. instinct, and what the difference is. I guess what I would say is that because of neurobiological studies like this one, I am increasingly coming to the opinion that there isn't a difference between will and instinct, and that the only thing that necessarily separates us from other animals is a written language (and possibly a spoken one as well, but complexity in dolphin 'names', and some monkeys as well makes me doubtful of that). Mice laugh, monkeys lie, and dolphins have names. At the risk of being a little bit too "Doctor Doolittle", maybe the only thing that is keeping us from realizing that animals "have souls" - have conciousness and will - is that we can't communicate in their language.