Rationality, or: Mistaking the Measure of Value for Value Itself

Ah, what a bliss to live in the prosperous 21st century! Finally, people are disentangling the mental chains of religion and guardrails of superstitious belief in order to come to embrace the only right (or should I say rational?) choice: rationalism. In the pursuit of dismantling the false idols of the past, the vanguard of science and technology, most prominently evolutionary biologist Richard Dawkins or neuroscientist Sam Harris, would most likely endorse such a characterization of the 21st century rationale, minus the over-exaggerations. Meanwhile, the scientific disciplines these thinkers have emerged from are reflecting their message: From AI over Game Theory to Cognitive Psychology, the leading paradigm is the (human) agent as a utility-maximizing information processor, i.e. rational agent. Who needs belief systems when you can simply be more rational instead? That is how you could sketch out their argument to be like. Rationality here shows to have instrumental value: Figuring out the most efficient path from point A (suboptimal present) to point B (less suboptimal future) by acting according to the laws of reason. Sounds, well.., reasonable, right?

The only problem though is the words’ circular definition, which might not become immediately obvious: Rationality is “the quality of being based on or in accordance with reason” according to Oxford Languages. However, as the laws of reason cannot be conveniently consulted through your advocate of trust, we might end up getting easily off-track in figuring out what they demand. We will have to break down the etymological common ancestor of rationality and reason in order to not be misled by the circular definition of rationality. Within the word “rational”, we find the root “ratio”, commonly only used in mathematical affairs. As one might remember from high school Maths (or derive from one’s intuition), a ratio quantifies the relationship between multiple numbers or measures. So, what does rationality have to do with millenia-old mathematics? It turns out that the Ancient Greeks were obsessed with ratios; balancing out the ratio between the four elements in one’s body was purported to be the source of health according to Hippocrates, insistence on the Golden mean, the harmonious ratio between two extremes, was not only reflected in the towering inscription on Delphi’s temple (μηδὲν ἄγαν – “nothing in excess”), but also runs as a connecting thread through the writings of Plato and Aristotle. What behavioral conduct these foremost thinkers of the Ancient West would have regarded as rational can be esteemed as being somewhat closer to the original meaning underlying the notion of rationality: A moderate proportionality between two things as a hallmark of rationality, which translates to treating the virtuous with their due respect, while scolding the vicious.

This ancient Greek notion of rationality is reflected up to this day in how modern societies conceive of the most rational approach in organising a society: All jurisprudence in Germany is subjected to the Verhältnismäßigkeitsprinzip (principle of proportionality), which demands that the measure for constraining individual rights or interests needs to proportional to the severity of the law’s violation. Achieving a proportionality between the degree of individual offense and that of the sentence is a legal principle so fundamental that it barely seems worth mentioning. However, the most omnipresent matters are often the least visible: The meaning of rationality as sound judgement according to a principle of proportionality.

Transferring the concept of rationality from the lofty spheres of law and Greek philosophy to the domain of less romantic decision making seems to be unproblematic, as long as we are dealing with

mathematically well-defined scenarios: When you have a 50 percent chance of winning money, let’s say by a coin flip, risking your stake for anything less than a doubling of your money in case you are right, is but irrational. It would be irrational, as you would not be acting in accordance with the proportionality of risk-to-reward ratio given in this well-defined scenario. This kind of irrationality is rather easy to spot but for many still hard enough to provide a reliable harvest for the multi-billion dollar business of betting. And this is possible despite the fact that the reasonable ratio of wager to possible win is clearly defined through the simplest of arithmetic. However, few scenarios encountered beyond the dubious world of betting provide a calculus through which we can come to figure out what the most rational action would be.

Academics like Nobel-prize-decorated Daniel Kahneman and Amon Tversky can lecture us about the lurking cognitive biases, leading to irrational decisions, and rightfully so, but their insights inform us about rational judgement only in a small subset of scenarios. These are namely the ones in which the game that is being played is mathematically well-defined. Deviating in them from the rational choice suggest an evaluative judgement: It is deemed irrational, i.e. misled, stupid. However, in domains where the boundaries of the game are not nearly as clearly delineated, conceptualising a situation the right fashion (with the right measure) already becomes an obstacle: In questions of what the morally right judgement or decision is, rationality alone provides not enough clues as to how to act. Figuring out what the correct judgement in a more complex scenario, e.g. as to how to react to your pinching roommate, is ends up not being an issue of figuring out the right reaction in proportion to the (sneaky) action confronted with but rather finding the right measure of the violation in the first place. Here, values and personal cultural biases come into play: Rationality can only help you in figuring out what the appropriate response relative to a given situation is but it cannot provide the grounds of evaluating issues of morality in the first place. Pinching somebody else’s sandwich might get you merely a scolding remark in some cultures, while it could get your hand cut off in others. How can we conceive of ratio-nality in terms of proportionality here when the severity of the violation is without the boundaries of what rationality is capable of single-handedly judging. Rationality works here as a function of value systems and not vice versa.

After all, rationality provides indeed a useful measure in how well your strategy is working with regards to a particular goal or value but it does not solve the problem of how to figure those out in the first place. Unfounded assumptions of value systems, like religions or political ideologies, are to be wary of but they cannot be overcome with means of simply “becoming more rational”. It means mistaking the measure of value for the value itself. Despite rationality being a majorly useful tool in order to see reality more clearly, for figuring out how to act, prioritize or decide it only works as a function of the values it receives as inputs. So when somebody tells you next time to simply “act more rationally”, check whether it might as well translate to “act in closer accordance to the value system I support”.