A student emailed me asking me about the role of doubt in a materialist/science dominated culture. It was an excellent question. What role would doubt play in someone who believed that science could find all the answers? We do doubt, but the materialist is often portrayed as a person with a particular sort of confidence in her worldview. The materialist not only believes that everything that exists or could exist is physical, or physically based, but that all such things can be given fully physical explanations as well. While not all materialists do believe such a strong claim, enough do to lend strength to the stereotype.
I suggested to the student that doubt is what drives materialism, and that it is doubt that the materialist uses to suggest it is superior to dualism. What follows is how I tried to portray this to my student.
I think that most materialists would accept the description of them as ‘big bang until now’ kind of believers. There was the beginning, whatever that was (and whatever that was, it was entirely physical), and, given the laws of physics, everything has turned out as it has. That we are able to peer into the earliest times of the universe with our telescopes backs up this materialist perspective. It is, of course, possible that there are places or parts of the universe that are not bound by the laws of physics, but that seems less and less likely the more we learn about the universe.
What of doubt though, you ask? Is it evolutionarily beneficial? I have not read much on that issue specifically, but I have read quite a bit about it in a roundabout fashion. Here is what I think a materialist/scientist would suggest as the role and purpose, naturalistically speaking, of doubt. We are born not as blank slates, but as probability machines. What that means is that while we are not born with knowledge of how the world works, nor are we born with no rules or inclinations at all. Rather, we are born with a set of ingrained tools that allow us to figure out how the world seemingly works. Babies and children (and some adults), rarely take things at face value, despite appearances to the contrary. A child does not know how gravity works until it has seen many things fall (and many things, such as balloons and planes, not fall). The child is constantly touching and tasting and probing its way about and through the world to learn what the world is made of and how it works. But, one might say, that is curiosity, not doubt. I think that is right — at least, partially right.
Curiosity is the drive to learn, but the truly curious, which children are, do not merely accept what they encounter. They seek out not just new experiences, but the commonality that exists between and within those experiences. That means that, along with the curiosity, there is doubt present. There is doubt that what the child has just experienced is enough to understand, is correct, is the right sort of standard by which other experiences can be judged. We doubt, though not always (or even often) in the philosophical sense, because of its survival benefits. Should I trust that sound, just because it was trustworthy the first time I heard it? Should I believe that all red fruits are healthy and all blue breads are bad? Doubt drives curiosity drives doubt. If we did not doubt, the first suspected causal unions would have been good enough for us. A virgin in the volcano seems to have forestalled an eruption, therefore, the gods have been appeased. What need would we have of science if we had no doubt?
Curiosity is the desire to learn, but doubt is the tempering of what we have learned into knowledge. A creature that does not doubt will not survive long. And it is doubt that is built into science itself. The idea of falsifiability is based on doubt. If there is no way in which a theory could be shown to be false, it is not considered to be a good or strong theory. That is doubt.
While we are or can be 100% certain of how things seem to us on a sensory basis (I seem to be seeing green; I seem to be tasting an apple; I seem to be hearing crunching; etc.), often what we sense does not fit with what we have previously sensed or with what we currently believe. That is where the doubt comes in. Suppose I hear a voice telling me it is Volthoon and that I must kill my neighbors. I cannot doubt that it seems to me that I am hearing such a voice and that I am hearing it say such a thing, but I can doubt whether there is such a voice saying such things. Maybe I won’t question it (there are many who do not), or maybe I will not think to question it (there are many in this group as well), but I can certainly accept what I am sensing as something that I seem to be sensing without also accepting that it is a real and genuine thing that has not been concocted by my mind alone.
If I were to see a cat bark like a dog, it would confuse the hell out of me, not because I would doubt what I sensed, but because what I seemingly sensed did not fit in with any of my previous sensory experiences. Now I wonder which belief or set of beliefs I will have to drop or alter (and there comes doubt again). Now I wonder if I can trust my eyes or my ears (see the McGurk effect for a cool example of this), or neither or both. This doubt leads to the “why” question, I think, though you are entirely correct that it is a question that I may never be able to answer.
Doubt, unsurprisingly, is the philosopher’s bread and butter and beer and pillow. We all want to know what is going on, but we all want to be right. Those are desires that are at unfortunate odds with one another, but they are so because we doubt. I am not sure that the world is a better place because we doubt, but I am reasonably sure that we have survived as a species, and, less importantly, philosophy has thrived as a discipline, because we do.