Rationality generally refers to the quality of being based on or in accordance with reason or logic. It involves the ability to think, reason, and make decisions in a way that is consistent with logical principles and evidence.
Assuming decision-makers are rational is key in the field of game theory, which analyzes decisions made by a wide variety of decision-makers, from consumers, investors, to political actors, and even organisms in the context of evolutionary biology.
Rationality should not be confused with unbiasedness. While all humans are biased in their worldview, the majority of them still remain rational at the same time.
In many models, the criteria for rationality include abiding by the law of transitivity (if a>b, b>c, then a>c), preferring good over bad, and being able to rank preferences.
As it turns out, the overwhelming majority of individuals are able to comply with these requirements, except for people with mental conditions such as autism.
Many organisms in nature have been observed to make decisions that maximize their efficiency in obtaining resources, such as food, while minimizing the energy expended.
In what is known as the “optimal foraging theory”, honeybees have been observed to learn and adapt their foraging behavior based on their experiences.
For instance, if a particular flower provides a high nectar yield, they are likely to return to that flower or similar ones more frequently. Conversely, if a flower is less rewarding, they will avoid it in the future.
Similarly, humans exhibit the same tendency to make decisions that optimize a certain outcome.
This is a simple yet crucial theme of human decision-making. If we, or at least most of us, are considered rational, this implies there exists an underlying calculus behind every decision.
While you may disagree with the values or outcome of a decision, the fact remains that there is a logical, underlying formula that drives humans towards choosing making decisions.
A substance abuser, for example, is not irrational for choosing substance abuse over discontinuing it. He is simply overestimating the present benefit in his value system and underestimating the future cost. He might be biased but this ties to a question of perception and values, not rationality.
Similarly, when a political actor behaves in a way you may not agree with, agreeing that the issue revolves around values and perception, rather than rationality, is a game-changer in diplomacy and mutual understanding.
It promotes this view that by using emotional intelligence, one can understand the other, and even in times of disagreements, there is something universal about human nature that unites us all.