The Limits of Scientific Reductionism
The following paper is something that I wrote for an Introduction to Metaphysics class that I took within the Philosophy department of Harvard Extension School, in December 2014.
Science has given us an untold amount of information about the natural world and how it works. It is particularly effective in explaining material phenomena, and the simplicity of its explanatory power is sought for all kinds of intractable problems. Science is largely seen as a reductive strategy, its explanatory power coming from the breakdown of physical phenomena to its simplest form. Philosopher Thomas Nagel has a problem with this approach. In his book, Mind and Cosmos, he argues that science’s reductive approach leaves out blaring explanatory gaps, like the origin of life and more specifically the origin of consciousness and the subjective self. Expanding on the mind-body problem, he ends up arguing that certain things cannot be known given the existing methods of science. Even with this, he neither offers an alternative explanation for the phenomena of consciousness nor creates an argument that goes beyond the idea that science’s reductive approach gives an incomplete explanation of consciousness. He ultimately makes an interesting yet repetitive case against reductionism.
It’d be helpful to explain in more detail what is meant by reductionism, or materialist reductionism. Materialist reductionism is the view that all phenomena in the world are solely physical. This would mean that all functions of the brain, including consciousness, would eventually all be explained in their simplest terms, by the laws of chemistry and biology. It is the view that by breaking down complex phenomena like the circulatory system into its constituent parts, we are more equipped at explaining said phenomena. This approach has worked fabulously well in developing our understanding of the human body and outer space, in part because phenomena follow from principles and throughout time empirical observation confirms this tendency and turns it into law.
The fact that we have discovered laws that govern phenomena make reductionism such an attractive viewpoint. An especially powerful law that has been used as a blanket explanation for the behavior of living organisms is the theory of evolution. The theory of evolution, though not Darwin’s original intention, has been used as a tool for scientific reduction. Scientists are able to explain the structure and behavior of organisms based on how fit they are for their environment. The general scheme of the theory of evolution is that random genetic mutation over a long period of time drives natural selection and creates the best-suited organisms for their environments. While this is the reduced, mainstream scientific view of evolution, Nagel is doubtful that what we see today is the “result of chemical accident, without the operation of some other factors determining and restricting the forms of genetic variation” (Nagel, 9). To Nagel, a purely reductive view of the universe’s evolution is a problem because it leaves out the origin of consciousness, in particular the ‘what it is like’ or phenomenal consciousness.
Another problem for Nagel is that the “prevailing doctrine” that evolution is the story of random mutation and natural selection is purely mechanistic. To his credit, it also plays to a certain bias. There is no overwhelming proof for this view; “it is an assumption governing the scientific project rather than a well-confirmed scientific hypothesis” (Nagel, 11). Scientists, philosophers and others want a tidy and consistent view of the universe. Admittedly, it’s hard to see why someone wouldn’t view the world this way. Someone who views the world as a series of processes reduced to physical terms and activities has a lot of evidence supporting them. To date, it has become the most effective way of explaining how the physical world works, but it is not nearly as effective at explaining how the mental world works.
Nagel’s main contention with the reductionist model is that it doesn’t give a satisfactory explanation for both the appearance and the origin of consciousness. In this way, he unites the project of science with the much-thought over mind-body problem. The question of how does the self, or consciousness, arise from the physical brain, and how they are different, is the source of an ongoing debate. One of the more influential views, one in turn influenced by materialist reductionism, is behaviorism. Behaviorism got rid of the subjective, the first person, and stated instead that mental concepts could be explained in terms of their behavioral conditions. Behaviorism dealt with the mental by leaving it out, which is incomplete as a method of inquiry.
People tried to get around this by relating a mental event (Y) to a physical event (F). Under this scheme, mental events could be broken down as physical events or brain states. This was called the psychophysical identity theory. Saying that Y = F implies that the two states are equivalent, but the question arises, what exactly makes the mental the physical? These theorists needed to synthesize mind and body by saying that the two states, mental and physical, are related by physical behavior. This revised theory, however, was ineffective at incorporating subjective impressions into a comprehensive view of mind’s activity. Rather, it ignored these impressions, disregarding an entire side of their Y = F equation.
Additionally, while the identity theorists may have argued that brain state and mental state are identical, they turn out to be contingent, rather than necessary truths. Philosopher Saul Kripke pointed out that when identity theorists make the claim Y = F, they were likening it to other physical identities like Heat = Molecular Motion or Water = H2O. In the physical cases, like water, all the properties of its chemical structure are represented in its behavior. At a certain point it melts, at a certain point it freezes, etc. In other words, “the intrinsic properties of water…are fully explained by H2O and its properties” (Nagel, 41). Similarly with heat and molecular motion, the generation of heat is exactly what is observed when speed at which molecules travel increases. The two properties are necessarily identical, representing their relationship with an equals sign. For the brain/mind, this is not the same. For Kripke, “the Y/F relation appears to be contingent,” not identical (Nagel, 40). Nagel uses this as evidence for the mental being separate from the physical, but the way it was just expressed, it seems that the mental originates from the physical. It’s when he discusses the mind body problem that Nagel’s argument starts to lose strength.
There’s been an ongoing debate concerning the origin of consciousness from the brain, as well as the structure and function of it. Unsurprisingly, the scientific method has illuminated many of our questions concerning how information is stored, even how emotions are processed throughout the nervous system. Making the claim that a theory which cannot explain something as intangible as consciousness “cannot account for the whole truth” to me seems presumptuous and may even highlight an ulterior motive (Nagel, 45). What he’s asking for is another scientific revolution. His dissatisfaction with science resembles that of a scientist from the 16th century who wracked their brain coming up with an origin story for the universe, or accurately, of a layperson who had a ‘system’ for revolutionizing the prevailing method for scientific discovery.
It can be said that what Nagel criticizes is the reduction of phenomena under the umbrella of natural selection. Reasonably so, natural selection has been the tool by which scientists describe the development of organisms. For Nagel, however, natural selection cannot explain the irreducible nature of consciousness, and why it appears the way it does in certain animals, the way it can explain its chemical structure and organization. A separate evolutionary theory has to be developed for the development of consciousness, one that accurately describes its “essential causal role in the survival and reproduction of organisms” (Nagel, 53). Furthermore, these characteristics would have to be passed down to future generations genetically. Claiming that consciousness is a byproduct is not enough.
Consciousness, specifically the development of phenomenal consciousness, would have to be an important enough event in the evolutionary timeline to become a key feature of the human brain. But is it reasonable to argue that consciousness of self, of subjective impressions, could have arisen outside of the physical aspects of the brain? It is one thing to be an eliminative materialist and argue that neither mental properties nor subjectivity exist. But it’s another thing to argue that emotions or personality traits don’t have a strong biological component. For example, we know that clinical depression can be quantified by an imbalance of neurotransmitters. A chemical imbalance in the brain has drastic implications for a person’s health and outlook. This is one case of how the biological are intimately related with the subjective. Furthermore, this is a case where the cognitive, and otherwise “more necessary” aspects of thought are damaged, alongside sense of self and feeling of place in the world. In order for the origin of consciousness to be explored, the phenomenal side will have to be studied as something connected to the strategic, or access side. No one will arrive at a satisfactory explanation of consciousness through conjecture. The real difficulty is in exhausting the study of phenomenal consciousness until correlations to the physical brain become less obvious or nonexistent. Even then, it will be very unclear how to study the mind without data from the brain. How could we come to study the mind without a physical platform? If we do so, how do we compare or measure different human experiences? Nagel seems to be frustrated at the idea that science has not developed those measurement tools yet.
Additionally, it is entirely possible that access consciousness, the awareness of one’s surroundings, has an adaptive value in tandem with other features of the mind, like abstract reasoning or the feeling of “’what it is like’ to be human. Our current reasoning powers as a species most likely have their roots in the survival instincts of our distant ancestors. Let’s say a predator is charging after us. Our qualia would tell us it is a dangerous situation, and reason would tell us to run away. Furthermore, reason would eventually tell us how to combat such enemies and survive. Given this, it is completely possible that these observations of cause and effect, combined with the evaluative nature of qualia, form the basis of scientific reasoning. Being able to observe one’s environment, and make predictions based off of repeated activities has great immediate, and long-term, value. Over time it is not hard to see how that can apply to curing an illness, or preventing someone from ingesting a poisonous fruit. Nagel is wrong when he says it’s difficult to see how the “manifestation of [reasoning] abilities [has] survival value in everyday life” (Nagel, 77). Even the study for theoretical physics, which isn’t as immediately helpful as the study of medicine, is still the application of the long evolved human reasoning apparatus. All that he is describing as characteristic of scientific inquiry, has its roots in early survival, which is itself an exercise in the awareness of one’s self and one’s environment.
In total, there are two points to take away from Nagel’s critique of scientific reductionism. One is that it hasn’t come up with a satisfactory origin story for consciousness, and the other is that consciousness, specifically phenomenal consciousness, is hard to examine. The difficulty in presenting the question of “What is consciousness,” in turn makes it difficult as an object of study. More so than making an overhaul of science’s current methodology, one should focus their efforts on locating the “person” inside the brain, and see how that connects to what we already know about the brain, such as centers of attention, sensory perception, emotional processing and memory. Is consciousness, the feeling of ‘what it’s like,’ somehow connected to these functional areas of the brain? These are the kinds of questions both philosophers and scientists should be asking.
If one were truly interested in exploring the topic, they would find a way of breaking down a large phenomenon into its constituent parts. This doesn’t mean that someone right now has the formula for integrating all the research going on in different parts of the brain into consciousness. But it doesn’t mean it’s an impossible task either. All the more measureable features of the brain make up what is commonly referred to as the self. The self is a large and ambiguous topic, but also one of extreme potential and growth. If we are studying these problems correctly, we will never exhaust our curiosity, like the philosopher who always asks “Why are we here?”
Works Cited
Nagel, Thomas. Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False. New York: Oxford UP, 2012. Print.
