I have always been somewhat of a science nerd and had what I consider to be a first rate science education at a liberal arts college. I had gone to this school on a football scholarship with the intention of becoming a phy ed teacher and a football coach, but the science education there was too compelling to ignore. I ended up being a biology and chemistry major and rapidly forgot about football. Brook's essay of what is science, what is the most compelling science and how that makes psychiatry as far from science as possible led me to think about memorable experiments from my undergrad days.
Experiment 1: The Limnology experiment: For a while in my undergrad career, I considered being a limnologist or fresh water biologist. My undergrad college was one of the first to emphasize the environment and ecology. A lot of the work involved doing population estimates of plankton and aquatic invertebrates. We spent hours classifying and counting thousands of organisms that are unknown to most people. We used various sampling techniques and statistics to determine populations of these organisms and whether they seemed to be influenced by any environmental variables. At one point I had equations from an journal article to calculate the probability that a specific species would be in contact with another one - called the "probability of inter species interaction." This is biological science.
Experiment 2: The PChem experiment: Physical Chemistry was the undergrad chemist's dream course when I was in college. You dreamed that you would be able to pass it. We had a text that was not very accessible, but a professor who was brilliant, very accessible and an excellent lecturer. I liked it a lot after we finished thermodynamics and moved on to other topics. Back in the 1970s we had very primitive computing power. Our lab had an old HP calculator that was as big as a current desktop with less computing power than a modern day scientific calculator. One of our tasks was to estimate electron densities around carbon atoms in aromatic hydrocarbons. In an afternoon in the lab we ran the numbers. This was the science of physical chemistry.
I have intentionally left out all of the details of the experiments because for the purpose of comparison with Brooks thesis they are unnecessary. From his essay we learn that biology and chemistry are real sciences with a "distinctive model of credibility". The examples I have given are from those fields. We learn that psychiatry is a "semi-science" because "the underlying reality they describe is just not as regularized as the underlying reality of say, a solar system". I will stop at that point because Brooks further examples rapidly degenerate. What do we have so far?
Looking at my experiments, #2 clearly has the regularity of a solar system. What could be more regular than the electron density for a specific molecule? It fits Brooks definition of science to a tee. What about experiment #1, the biological experiment? Here we have a number of organisms. Some have nervous systems and the others (eg. phytoplankton) do not. I did a series of calculations to look at the probability of one species encountering another. There were certain assumptions to those calculations about randomness to make the calculation much easier to do. But what if I wanted for a moment to be a "behavioral limnologist" and attempt to predict the behavior of a specific stoneflies in the sample? What if I wanted to determine the 5% of stoneflies that exhibited behavioral characteristics, that differentiated them from the other 95%? Suddenly we have a problem. The source of that problem is a nervous system. The underlying reality of most even slightly complicated nervous systems is that they will never have the regularity of a physical system. They have evolved not to. Regularity in a nervous system locking it into a physically predictable system is not in any way adaptive for any animal that needs to forage and reproduce. It is the kiss of death.
But is gets complicated at additional levels. The human brain is highly evolved to have significant processing power. At another level, there are theoretical concerns about whether it is possible to ever to map behaviors and psychiatric symptoms directly onto some neurobiological system. Unlike my experiment 1 above we are rarely interested in looking at only life or death as the outcome variable. The variables that will allow us to study different populations are going to be much more complex than grossly observed behaviors. There is a complicated nervous system between those behaviors and the environment.
Is psychiatry really not a science because it is complex and attempts to deal with the complicated phenomena associated with the human brain? Should we ever be concerned about 1:1 mappings of psychiatric disorders onto a specific genetic or neurobiological defect? Is it possible that a human nervous system is so complex that it is unrealistic to expect that this might happen?
Unlike Brook's theme nobody is a "Hero of Uncertainty". Uncertainty is the expected condition and one that every psychiatrist should be comfortable with. Psychiatry and the associated neurosciences will never be reduced to the predictable calculation of a physical system and that has nothing to do with one being a more prestigious science. It has to do with evolution and complexity. It has to do with what philosophers call the "demarcation problem" between what is and what is not science. More to come on that in the near future.
George Dawson, MD, DFAPA