2. The Argument against Philosophy
Dissensus can be used in an argument against philosophy:
The Argument against Philosophy . The goal of philosophy is to uncover certain truths. Radical dissensus shows that philosophical methods are imprecise and inaccurate. Philosophy continually leads experts with the highest degree of epistemic virtue, doing the very best they can, to accept a wide array of incompatible doctrines. Therefore, philosophy is anunreliable instrument for finding truth. A person who enters the field is highly unlikely to arrive at true answers to philosophical questions.
This is a rough sketch of the argument. I will refine it as necessary as the paper proceeds. Note that Argument against Philosophy need not claim that no philosopher has found the truth. It is possible that Kant got everything right. Yet, philosophy also has arrived at hundreds of other incompatible doctrines. If philosophy leads to the truth, it is only because it leads almost everywhere.
A person concerned only to get the truth would at the very least try to believe some randomly chosen doctrine rather than be agnostic, since there is at least some possibility that a random doctrine happens to be correct. She might even pursue philosophical methods if they increase the probability of being correct, as it is possible they do. Perhaps philosophers are twice as likely to have true answers to philosophical questions than non-philosophers are. However, if this same person is equally concerned to avoid false beliefs about philosophical issues, then she would want to pursue philosophy only if it gave her a greater than 50% chance of getting a true belief. Given the degree of dissensus in most fields of philosophy, it seems unlikely that philosophy offers her this great a chance.
Here is an analogy. Suppose, thousands of people, each of whom wants to go to São Paulo, randomly board all flights departing Dallas-Fort Worth. Suppose they fill all departing seats, but are not told where they are going. Of these thousands, a few hundred in fact will land in São Paulo. Most will arrive somewhere else. Philosophy seems like this in many respects. It may bring some people to the proper destination, but it dumps most somewhere else. Actually, matters are worse than that. Travellers will know whether they have arrived in São Paulo. In philosophy's case, some may indeed arrive at truth. However, they will not have discernibly better grounds for believing this than their mistaken peers. They may believe themselves to have better grounds, and their peers believe this about themselves as well. However, from the outsider’s perspective, they look the same. They are smart people doing the best they can, and they disagree. The outsider has little reason to think one philosopher is closer to the truth than the next, and little reason to think that if she became a philosopher, she would do any better.
Here is another way of making the unreliability argument. Suppose that there are 10 competing doctrines in the field of philosophy of mind, each of which is accepted by 10 percent of the members of the American Philosophical Association. Suppose, optimistically, that on the nature of consciousness 10 percent of the members of the APA have the right theory. Suppose also that we can regard all members of the APA as epistemic peers, where two people are epistemic peers just in case they are equals with respect to their degree of epistemic virtue (thoughtfulness, freedom from bias, etc.) and their access to evidence.[^2] An uncommitted person, looking at the field from the outside, would worry that if she pursues philosophy, she will have something like a 1 in 10 chance of getting the right answer to the questions of the philosophy of mind. She sees that philosophical methodology—studying arguments, making new arguments, creating new distinctions, reading texts, debating, etc.—generally leads people to accept some theory or other of the nature of consciousness. (Let us assume that everyone who studies the philosophy of mind ends up accepting 1 of the 10 theories.) So, she knows that philosophical methodology will result in her accepting some theory, but from her standpoint, it is more likely than not that it will be the false theory. The greater the degree of disagreement among epistemic peers, the lower the probability that philosophizing will get her to the truth.
This argument assumes than an agnostic outsider who ends up pursuing philosophical methods will have either a random or proportional chance of accepting any theory. I.e., I am working on the assumption that she will either accept a theory at random or with a probability proportional to the percentage of her epistemic peers that accept any given theory. Real people probably do not have a random chance due to their background starting beliefs. A person who comes to philosophy as a Christian is probably more likely to end up being a moral realist and a natural law theorist than his atheist counterpart. A graduate student who studies ethics at Harvard University is probably more likely than a student at Australian National University to become a Kantian. People have dispositions towards one theory or another, and (in certain respects) non-random factors such as the people with whom they study philosophy affect the probability they will adopt any particular theory. Suppose, however, that our truth-seeking, error-avoiding agnostic has no such dispositions and manages to have even exposure to all competing doctrines. Will pursuing philosophy assign her to a set of beliefs randomly or in a probability proportional to the positions of her epistemic peers? Perhaps the agnostic will remain agnostic since she has no dispositions. Without a good empirical account of the mechanisms of belief formation, I cannot be sure whether she has a random chance of adopting any particular theory, adopting a theory with a probability proportionate to the percentage of comparably virtuous philosophers accepting that theory, or has some different probability altogether. From her viewpoint, the process will seem random in some way. So, I use randomness here as a hopefully good-enough substitute for the actual mechanism that assigns beliefs.[^3]
Under some circumstances, it could be reasonable for the outsider to think she has a better chance than others do of getting things right. For example, consider a an exceptional person with an IQ many times greater than that of the average philosopher, with an exceptional memory, who lived long enough to read every philosophy book ever written, and who exhibited the epistemic virtues far better than Kant or Hume did. This person could legitimately conclude that she might do better than other philosophers have. However, no real agnostic will be this exceptional. A good response to the sceptical worry should provide reason to pursue philosophy for a truth-seeking, error-avoiding agnostic with epistemic virtue comparable to a typical philosopher’s.
Philosophers do seem to aim for truth. Philosophy’s state of dissensus may show us that philosophy is not worth doing if truth is our goal. Pursuing philosophy is not a reliable method of finding to the truth about philosophical issues.