The soul is a real sacred cow. People hear about the soul, or the spirit and they don’t even flinch. Obviously, these same people don’t stutter when they talk about using their brains. To many, the soul and the brain are not mutually exclusive, and some neuroscientists have even claimed to have discovered proof of the soul within the human brain. As a student of neuroscience, I view such “proof,” and further any misguided attempt to find it, to be reprehensible and not within the purview of science.

First let’s define some terms. By soul, most people mean some ephemeral, transcendental presence of being. People view the soul as the source of individuality, thought, and morality. When they discuss the soul, people mean something which can survive death, something indestructible and supernatural.

The brain, in contrast, is an organ. Pure and simple, like any other organ, it is made of cells. It has a job, which is to interface all of the information of the body to maintain the necessary equilibrium for life, called by scientist Claude Bernard Shaw, “the internal milieu.” Thinking happens in the brain. One way we have learned this is that when brains are damaged in certain places thinking is impaired in a predictable way. This is how we did much of the original mapping of the brain in neurology, and first identified the relationships between the brain, and thought.

Recently, medical scientists developed a marvelous machine called an fMRI (functional magnetic resonance imager) which can show what brain regions are engaged in oxygenation, and therefore presumably activity, as a subject completes a task. Before, scientists and doctors had to rely primarily upon accidents and diseases to damage sections of the brain, and observe differences between damaged and undamaged sections. Now we can observe and map the regions of the brain without ever even picking up a scalpel. You just lay in the middle of a great big round magnet while it literally reads your mind.

Don’t get me wrong, fMRI cannot project an image from your imagination onto a screen. But it can tell us what parts of your brain are more active than others, and because of what we are learning about the functional purposes of different brain regions, we can deduce a great deal about what’s going on in your mind.

So let me recap, the way your mind works is affected by the physical condition of your brain, and when your mind is doing stuff, specific brain regions get activated by what your mind is doing.

Given what we know about the brain– its restrictions and possibilities, the way it works– how can anyone maintain that thought, identity, and really any part of who we are originates anywhere else? By anywhere else, I of course mean the soul. How do people maintain support for a belief that has no factual basis in science? It’s because they aren’t really thinking about the implications of neurology.

Let me tell you my favorite case study, it is a universal part of any education in behavioral and brain sciences. It is when we began to understand to what depth what makes our personality is in the brain.

It was on September 13, 1848. Railroad foreman Phineas Gauge had a terrible accident. Phineas, by all accounts, was an exceptionally good man, a leader in his community, and a reliable man to all who he encountered. Then a railroad spike was blasted in through his skull and out the other end, destroying a region known as the prefrontal cortex. If you can imagine the area right behind your eyes, that’s about it. In the movie Hannibal, during the famous scene in which Hannibal Lecter feeds Ray Liota his own brain, he calls the prefrontal cortex, “the seat of good manners.”

Well, it turns out we know this because of Phineas Gauge. When his prefrontal cortex was destroyed, so was his likable personality. Phineas Gauge became a violent and belligerent man, and a pain to be around. This phenomena is universal in all people who suffer prefrontal cortex damage. It really is, “the seat of good manners.”

The question I’d like to pose, and the question which I see our knowledge of neuroscience as making impossible to avoid, is where was Phineas’ soul? If we accept that our morality is derived from some supernatural source, then damage to our physical bodies shouldn’t result in damage to our moral compass. If we accept also that the soul is immortal and imperishable, then no amount of suffering, and no amount of violence could have robbed Phineas of his good character.

Before I go too much further down this path and invite even more ire than I’m undoubtedly going to, I want to end this with a reminder of my initial point. Science and spirituality are incompatible. There are many scientists who are deep, sincere believers, and I’m not suggesting that should be disallowed. But when they try to turn science into a justification of the unjustifiable, they have exceeded the bounds of their mandate as scientists. Let’s leave the theology to the priests, and focus on solving real problems.