How do we know that people have preferences?
There are four ways of going about to answer this question.
(1) God created man with preferences.
(2) I have preferences. Therefore, to the extent that other people are similar to me, other people also have preferences.
(3) People reveal through action the behaviors which are consistent with preferences existing.
(4) I don’t know that people have preferences. Perception is fallible and subjective, and it is the only way in which I can perceive the world.
Really, the above question is just a proxy for another question “How does one know anything?”
There is an ‘a priori’ problem with each of these answers and none of which is necessarily wrong. The problem is that none of the statements can be either proved or disproved empirically. They are all based on initial premises – assumptions about the world which are frameworks for how to approach interaction with our surroundings. Although one set of assumptions may lead to more useful implications for discovery and more fruitful results from inquiry, the fact that each of the answers above are based in a premise opens the door for each them to have deductively valid syllogisms which flow forth.
No one would argue whether answer (1) is built upon faith. Although the conclusions that flow forth must be valid with the assumption, no one can refute the initial premise one way or the other. This is recognized by theists and non-theists. But I contend that the other answers are just as much assumptions which may as well be called faith.
Answer (2) is itself built upon premises. “I have preferences” is itself an implication that self examination yields fact and that, more generally, the senses also yield facts. It also assumes that one can think about thinking and trust the results. Huh? That’s more than a little opaque. Conclusions from introspection require that the observations be ‘contaminated’ as an endogenous part that which is being examined. We can’t very well think about our thinking without depending on the validity of the very thing about which we are inquiring.
An example of the conundrum raised by answer (2) is the classic ‘proof of will’. The story goes: Two people are arguing about the existence of free will. And the proponent in a fit of exasperation says “I can prove that I have free will. If I want to raise my hand, then I can do it!” He then thrusts his hand into the air and looks intently at his opponent, challenging him to refute the obvious. But the implication of free will, from the action, is not sound. The proponent’s decision to raise his hand was endogenous to the external circumstances and arrangement of everything inside of his own brain. Indeed, if physics and chemistry are true – that is, if logic describes the world – then how could the proponent have done anything except raise his hand? Was it not determined as a function of his own composition? The proponent is attempting to prove the independence of some mass of matter by interacting the matter with the rest of the world. ‘I have preferences’, argued this way, is a foregone conclusion. It is an assumption. It is faith.
Also nested in the assumptions for answer (2) is an implied way to measure the similarity of another person to one’s self (Which is another post: That Special Something).
In truth, answer (3) doesn’t answer the question of whether people have preferences. It answers another question which is “Why should we think that people have preferences?” The answer is consequentialist. It’s not concerned with whether people do in fact have preferences. It merely induces preferences from action. This is part of the study of praxeology – the study of human action. Preferences are a construct which help describe actions. No one has ever seen or dissected a preference. Talking about whether it exists isn’t really the point. Whether they can be used as a tool to explain behavior is what makes them worth describing AS IF they exist. In this view preferences are an analytical tool imagined to exist because they help describe behavior. Whether preferences actually exist is irrelevant to whether there are fruits from imagining that they exist.
Answer (4) appeals to the subjectivists and existential nihilists. It’s not clear that such a stance is helpful. It need not imply that nothing exists or that human perceptions are always wrong. But it does say that there is no reason for perceptions to reflect reality. The two need not correlate. People of this stance are reduced to deductive logic which is based on assumptions. The truth of the assumptions is negligible. But the logic can be valid regardless of the truth. So, the claim about preferences existing would be a premise in the beginning. Not something derived or true from observation. Other assertions may be consistent with the premise of preferences, but these conclusions would only be true to the extent that premises are also. Answer (4) suffers the same shortcoming as does answer (2). It assigns to a proposition validity based on a process that demands use of the initial proposition. That is, regardless of the truth of preferences, even using them as a premise in a syllogism assumes that deduction is a valid tool and reflects the real world. Just like a person can’t prove that preferences exist by invoking preferences, logic can not be proven by using logic. It’s a conundrum.
Personally, I don’t like the question. I fall in the camp of answer (3). I don’t know that anything necessarily exists. Indeed my perception is inaccurate. But that doesn’t stop me from pursuing goals and being happy. We all interact with matter in the world based on assumption in order to get what we want. We don’t know the infinite particulars of each atom and its relation to all of the other atoms. We have incomplete information and we do our best within the constraint of our own conception of cause and effect. My favorite example is of cutting a bell pepper. I don’t know the placement of each cell in the pepper. I don’t know how thick the skin is or the rigidity of the cell walls. I don’t know how many edges there are on my serrated knife. I just know how to manipulate my own body, the knife, and the pepper in order to end up with slices of pepper. Assumptions fill the gaps of our information so that we can interact with our surroundings.
Complete information doesn’t exist. Indeed, the concept is over-rated. It would be very costly to discover all of the information that could be used in cutting the bell pepper. But the cost would outweigh the benefits. Assumptions help to decrease the cost of actions because they get us what we want with varying efficacy. When people make bad assumptions, they change their premises the next time. Whether preferences actually exist isn’t terribly relevant. What makes a good assumption is not the accuracy with which it reflects objective truth. Good assumptions are those that help us get what we want. If the goal is to model our perception of human behavior, and the assumption of preferences helps us attain that, then to neglect preferences would be to increase the cost of discovery and forego a valuable shortcut in our studies of complex social phenomena.