Man is not a rational being but a subjective one.
Humans cannot perceive anything outside of themselves although their senses give them an illusion of doing so. But what people actually do when they see, feel, smell, touch and hear is to experience sensations occurring entirely within themselves.
All decisions that humans make are therefore based on perceptions that exist only inside their own individual bodies defined by its envelope of skin. Further, our senses are designed to perceive things that are useful to us, not to study the nature of reality. Our senses are tools we use to find the things we want and to avoid adverse consequences to ourselves. We generally only look for things that we want or want to avoid. Our vision is used to drive our car or make our way down the street, to avoid obstacles, find food or entertainment, spot a potential mate or to watch a movie, TV show, video game or piece of art that it interests us to look at.
What people look for, seek out, want and desire are the things that interest them at a specific time and place. They may go about their quest in a logical, haphazard, enthusiastic or desultory way depending on how they feel at the time. And what they want may be hurtful, harmful, helpful, fun, silly or sexually arousing to them.
How do we fit rationality into this entirely subjective structure that we all live in all the time? For example, imagine an unhealthy, unhappy person named A who is obese and suffers from diabetes. A has been repeatedly warned by his doctors against binging on ice cream. While A occasionally refrains from going out for ice cream, A now decides to put caution aside to get a half gallon of Häagen-Dazs chocolate fudge brownie ice cream. A may now quickly develop a quite logical plan to obtain the ice cream by going to the nearest store that usually carries it and bringing sufficient funds or a credit card to pay for it.
A is setting about this expedition in a perfectly logical way making sure that he has everything he needs to secure his ice cream goal. But is A acting rationally? One supposes not because A may even kill or harm himself further by devouring the ice cream. But what do we then mean by “rationally”? To be a rational act, must the goal itself be rational or the manner in which one sets about achieving it?
Rationality it turns out is a characterization that can only be judged by an observer in relation to a purpose. And that purpose can only come from some interest of the actor in the matter. Human desires and motivations are not known for their rigorous application of logic.
The term “rational” and “reason” are usually thrown around casually as though they had an agreed upon meaning. But describing something as “rational” is a purely subjective characterization. It is not a factual statement. It is like saying an act is “good” or “bad”. That kind of judgment makes no senses unless one knows what the act is “good” or “bad” for. By the same measure, one must understand in what relation to an act it can be said to be “rational.” Must it be rational in its conception, its execution, or in its ultimate aim? And who is to make this subjective judgment of rationality and based on what set of values?
If an Islamic terrorist is on Jihad, it is quite rational for him, based on his belief system and values, to blow up a government building or stadium or other target where he can inflict the greatest possible number of casualties and get the most press coverage. And most such attacks are planned with precisely those considerations in mind. But to others, the result of this act is the senseless murder of innocent bystanders. How can this be a rational goal? In the mind of the terrorist it is rational, because the terrorist believes his goal is more important than the lives of innocents.
Even in the most basic kinds of decision-making there is an unresolvable disconnect between goals that might be considered rational. Is it rational to sacrifice one’s life in the military? Or is it more rational to desert one’s unit and save one’s life. Rationality is entirely relative to the conception, means and purposes of the act and is in any case only a subjective judgment by an observer. It has no objective meaning.
Just as time runs faster or slower relative to the velocity and distance of two observers, so the idea of rationality is relative to the purpose or goal with respect to which it is being judged. Like time, rationality is not an objective absolute. It changes depending on who and where the observer is.
People hold up “reason” and “rationality” as the solution to all human problems. ‘If only people would behave rationally,’ we sit and think. ‘Why can’t everyone just be sensible,’ we muse to ourselves.
Rationality it turns out, if it exists at all, is not an absolute. It can only be judged in relation to a goal. And wouldn’t you know it; all goals involve subjective interests. Yet subjective interests cannot really be judged as rational or irrational. They are simply the desires of a being. Only our famously non-existent objective observer can ultimately judge whether our acts are rational or irrational.
So we see that rationality is not easily attributable to human desires. We simply want what we want whether it be a drink, a cigarette, a mouthful of chocolate or 100 million dollars. Once we have a goal in mind we can use reason to achieve it. You can just stagger up from the couch and rummage through all your coat pockets until you find a pack of cigarettes. That is using reason. Or if you are hungry, you can think about which restaurant to go to.
But this does not mean that humans are rational beings. Far from it. They are subjective beings, capable of operating only within the envelope of skin in which they find themselves. And it is the needs of what is contained in that envelope that they will most often be preoccupied with, regardless of what the rest of the universe is up to all around them.