A few centuries ago, one form of language use to persuade people became predominant in many areas of life—rational argument and logic. It is not that people could not use this before, but they were mixed in with other ways to convince people as well—primarily through social relationships.
‘Rational’ is based on the outcomes for the listener, what is in it for them—what are the immediate consequences from the environment for the recipient. The other persuasions are actually also about the consequences but those other consequences are social outcomes for the recipient—social relationship consequences.
So, people could certainly use reasoning and logic prior to their huge rise, but what happened during the Enlightenment (so-called, ironically) was that social forms of persuasion and getting people to do things became actively excluded from many discourses leaving rationality as the dominant or exclusive discourse (cf. Foucault, 1970). So rationality and logic were available prior to this, but they became more prevalent; not because people began believing in their superiority, at least not initially, but because other forms were excluded.
Whatever the reasons, rational persuasion became prevalent (describing and using the outcomes from the environment regardless of any social outcomes), and ushered in a new era during which the use of non-logical or non-rational ways to draw conclusions or to act were considered highly negative, and often punished. Ever since, acting in ‘non-rational’ and ‘non-logical’ ways have variously been punished, negatively labelled, laughed at, or used as a reason to exclude or control people.
The problem with this, however, is that the social outcomes are often the most important outcomes for everybody! If you have a choice of $20 or $1 and you choose the $1, you are acting in an economically irrational way. But if choosing the $20 will make you look greedy and lose you friendships, then the social outcomes are far more ‘rational’ and you should take the $1.
Science has always been thought of as perhaps the one domain in which we mostly need to pay attention to the environmental outcomes very strictly; to believe what the data tell you not what someone just says is true (and I agree). But we are now seeing the wayward outcomes of this in environmental degradation and not paying attention to at least some of the social outcomes when messing with the environment. This mostly occurs when we do NOT have the data but scientists (or those who pay them) want to pretend to have a rational answer (that is, when constructing theories and models).
Here are some other domains in a Table, which gives the rational discourse, the common rebukes for not acting ‘rationally’, and just a few of the positive social outcomes when using both social and environmental outcomes to guide us (it does not have to be either/or; we can do both).
Click on the above for Table.