I’m taking a seminar on Derek Parfit’s new book On What Matters this semester. In it, he defends an Objectivist account of reasons. Roughly stated, this view claims that the normative force of reasons concerning our attitudes towards an object stems, not from our subjective desires concerning that object, but from the nature of the object itself. In contrast, a Subjectivist account of reason basically says that the normative force of reasoning comes from our subjective preferences. The way Parfit sets up the debate, most metaphysical naturalists and empirically minded moral psychologists essentially accept a Subjectivist account of reasons, and they do this based on evolutionarily considerations. This empirically minded Subjectivist tradition stretches back at least to Hume, who said that “Reason is, and ought only to be the slave of the passions”. This tradition has tried to argue that pretty much all reasoning is a matter of post-hoc rationalization for prior emotional convictions. This tradition has been recently taken up by people like Jonathan Haidt, who have argued that Reason is the tail being wagged by the emotional dog, and not the other way around.
Most people in the seminar are very skeptical about Parfit’s Non-Naturalist Objectivism, which makes out Reason to be this very mysterious and spooky thing, that seems to have magical normative powers to compel us to act in certain ways. Most people in the seminar, including the professor (Julia Driver), seem to basically accept the standard Humean account of Reason as the best and least mysterious account in the market.
Personally, I do not believe in the Humean story. I do not think that Reason is the tail, and emotions are the dog wagging that tail. I think the slave-master metaphor is a bad one, because both Reason and Emotion are masters in their own way. Let me explain. First of all, in order to tell my story of Reason, I need to make a distinction between what I will call instrumental rationality and Human rationality (for lack of a better term, though I think you could substitute conscious here just fine). Instrumental rationality is the rationality we share with all nonhuman animals in virtues of being the types of entities who have survival programmed into their genome. So if I am starving it is instrumentally rational to eat some food. If I am being attacked by a wild boar, it is instrumentally rational to try and defend myself. So far, so good. Instrumental rationality is not very mysterious and the normativity of instrumental rationality is fully compatible with a Subjectivist, Humean account.
However, I do not think Human rationality (or at least human-typical rationality) operates according to the same normative logic. I think there is a different normative structure in operation that governs the rationality of Human Reason. So this leads to a natural and obvious question: What is Human Reason? I propose an answer: a tool. Human Reason is a tool that is a product of cultural evolution, in the same exact way that Dan Everett has recently (and convincingly, imo) argued that language is a tool, in the same way that a bow and arrow is a tool. We do not grow the ability to make bows and arrows, we learn how to make them. Likewise, we learn language. And similarly, I am claiming, we learn to be Rational.
If Human Reason is a cultural tool, then it is going to operate according to a different evolutionarily logic than instrumental rationality. I see no reason why we should apply the Subjectivist story about instrumental rationality to Human Reason. They are simply very different things, although of course Human Reason bidirectionally interacts with instrumental rationality in very complex ways. I believe the story I am telling about Human Reason vs instrumental reason is more or less compatible with modern dual-process accounts of reason. On dual-process theory, there are basically two different reasoning systems in humans: one is evolutionarily ancient and shared with nonhuman animals, and one is evolutionary recent and likely unique to humans. My particular claim is that the reason why System 2 is evolutionarily recent is because it is a product of cultural evolution. Being a Jaynesian, I believe that Human Reason was “invented” through the mechanisms of cultural evolution very recently, perhaps within the last 10,000 years.
Moreover, I believe that philosophy as a cultural practice represents the loftiest instantiation of Reason as a tool. When humans invented the practice of philosophy, we developed a cognitive toolbox that opened up new vistas for human development. Indeed, natural philosophy itself eventually transformed into perhaps the most powerful tool of all: modern science. Science is the ultimate extension of Human Reason as a toolkit. It allows us unprecedented control over our environment. It allows us to, for example, surf the internet on our tablet computers while (someone else, hopefully) is driving a car which is being guided by GPS satellites. Science as a tool also allows complex feedback loops with instrumental rationality in virtue of the development of medicine as a means to prolong and maintain our biological health.
I started this post with a brief overview of the debate between Objectivists and Subjectivists about Reason. I rejected Parfit’s Non-Naturalist Objectivism because it makes Reason out to be this spooky, magical thing. But I also rejected Subjectivism for inappropriately applying the normative logic of instrumental rationality onto Human Rationality. The normative structure of Human Rationality is closer to Objectivism. However, I offered a cultural explanation for the origin of Human Rationality. Human Reason is a tool, in the same way that a bow and arrow is a tool. Just as there is (probably) no unique gene for making a bow and arrows , there is not a unique gene for Human Reason. It is a social construction. Which isn’t to say that there are not particular neural dispositions underlying our capacity to learn Human Reason that have a definite genetic basic. To say that Human Reason is a tool is to say that our brains do not grow the capacity for Human Reason, but learn it. For me this is essentially an optimistic picture, for it flips the depressing story about the dog and it’s tail around. Although emotion is certainly a force to be reckoned with, so is Human Reason when properly wielded. Not constrained to the evolutionary logic of spreading genes, Human Reason can allow humans to rise above the selfish-programming of genetic evolution and strive for decision making that is based on the application of principles that we have given to ourselves in virtue of our capacity to step back and think about what we ought to do. This gives me great hope, for it means essentially that Reason is not and ought not to be the slave of the passions; they are both masters in their own way.