Giacomo Melis (University of Stirling) & Susana Monsó (UNED), "Are humans the only rational animals?"
The Philosophical Quarterly, 2023
By Giacomo Melis and Susana Monsó
Imagine that you want to know where this week’s departmental seminar will take place. You ask your office mate, Nadja, who tells you that it’s in room A. You go to room A and find that it’s empty. You sit and wait for your colleagues, assuming that everyone is late, while, unbeknownst to you, the seminar is actually happening in room B. Because Nadja had misinformed you, you end up being ten minutes late for the seminar. The following week, when Nadja tells you that the seminar is in room A, you decide to double check on the departmental website, just to make sure.
Imagine now a different scenario. You go to the hair salon to get your hair dyed. The hairdresser pulls out a selection of colour samples for you pick from. You choose one and leave the salon feeling happy about your new look. However, once you get home and look in the mirror, you realise that the lighting at the hairdresser’s wasn’t quite right and that the dye is actually a much lighter colour than you would have liked. Next time you go to the hair salon, you ask to take the samples out onto the street so that you can look at them under natural sunlight and make a better informed decision.
In both cases, we think it’s safe to say that you are acting rationally. You have realised that your office mate is an unreliable informant and that the lighting at the hair salon is not trustworthy, and you have taken measures to ensure better outcomes in the future. These cases exemplify your rationality because they show that you are capable of responding to “undermining defeaters” that suggest that some piece of evidence may be misleading. Nadja’s past mistakes don’t guarantee that she’ll always be wrong, the same way that the lighting at the hair salon doesn’t guarantee that you won’t like your hair once you make it home, but in both cases they give you good reason to look for more information before making a decision.
If you, like us, believe that cases such as these exemplify an agent’s rationality, then you, like us, will have to conclude that humans are not the only rational animals. Read our paper to find out why!