Think of a well-engineered car: an engine with good horsepower, sound suspension – capable of navigating numerous types of terrain. Assume that it has to go from point A to B via a thin, rather arduous patch of road. The degree of success, then, is dependent not only on the car itself, but also on the proficiency of the person driving it. While the line between the two is thin, once visible, it cannot be overlooked. Intelligence becomes the car, and rationality the driver. The car is a given; unalterable and permanent. The driver’s resourcefulness, then, determines the probability of reaching the destination. In casual conversation, intelligence and rationality may mean the same; however (counter-intuitive as it may sound), they are only weakly correlated, and therefore, largely independent of each other.

Intelligence is defined as “ability to efficiently achieve goals in a wide range of domains”, while rationality is “the art of choosing and implementing actions that steer the future toward outcomes ranked higher in one’s preferences”. Intelligence – quantified by IQ – is a measure of how easily one picks up various skills (the “theory” component). Rationality (measured by RQ) is the ability to use acquired skills, account for various innate cognitive biases, other non-cognitive domains such as empathy, socio-economic factors and make decisions to deliver a desired outcome.

From an evolutionary standpoint, intelligence precedes rationality. Jared Diamond hypothesised that an average tribesperson of Papua New Guinea is more intelligent than the average European, his rationale being that European countries have a good standard of living and good accessibility to important services, while in the case of the tribes, isolation from such facilities presents challenges to the continuation of life on an almost daily basis. Meeting these challenges requires intelligence, synonymous with adaptability. Simultaneously, perfect rationality is never possible. This is for two reasons: first, the number of cognitive biases is so great that we do not have the ability to account for all of them. Secondly, any previously acquired knowledge is inevitably associated with certain prejudices – more so in the case of people with higher IQ.

Unlike IQ, however, RQ is not an unalterable quantity; one may make himself “more rational” by learning about the thinking errors and fallacies the human mind has a tendency of committing, and avoiding them in practice. Greater rationality leads to a happier future, as it signifies agreement between one’s actions and one’s view of the consequences of those actions in the future.

In hindsight, it becomes apparent that rationality and intelligence are differentiable attributes. Ernest Hemingway once mused: “Happiness in intelligent people is the rarest thing I know”. Intelligence (here) encompasses self-awareness – knowing one’s capabilities and limitations; the good and the bad embedded within. Focussed on the possibilities these entail rather than actually pursuing them, intelligent people often swim in rivers of self-doubt and self-hate. Rational people skip straight to the answers, and are able to get what they desire out of such situations. Morality and ethics are unimportant, insofar as they are able to fulfil their own needs. Intelligence becomes severely debilitating; rationality frees us from its chains as long as we learn to forget what we assume we know.