If you hear hooves you think of a horse, not of a zebra. Unless you live in Africa


“If you hear hooves you think of a horse, not of a zebra”. Unless you live in Africa.  

When faced with a problem, we do not always look for the easiest explanation, however, in the overwhelming majority of cases it is the right one, a clear reference to “Occam’s razor”. This is what I talk about with some students, who lose themselves trying to find solutions while forgetting about simplicity. 

Occam’s razor, also called “principle of economy” recommends doing without superfluous hypotheses when trying to explain a phenomenon, in other words: in the presence of two seemingly equally valid solutions to a problem, the simplest one should be preferred. 
Basically, it is not worth complicating a theory or adding elements to a discussion unless it helps to reach the solution or make something edifying. 
Occam’s principle, for which its postulator was accused by the Church of heresy, is used indiscriminately in philosophical treatises, for everyday matters, but also on great scientific themes, for example nature and the composition of the universe. 

Failure to use is a characteristic of pseudoscience, in all those cases in which we try to explain a more or less mysterious phenomenon by suggesting other even more improbable ones. For example, it is still not yet totally clear how the ancient Egyptians managed to build the pyramids: we could speculate that they did it thanks to advanced technology provided to them by alien civilisations, however, following the principle of economy, it would be preferable to assume that they managed alone by ingeniously exploiting the knowledge of the time. 
In this way, we are not obliged to hypothesize a series of particular conditions – that aliens exist, that they managed to reach the Earth, to communicate with the Egyptians and then disappear without leaving any trace – and we can explain the same phenomenon, the pyramids, using less hypotheses. 

The importance of Occam’s Razor lies in it forcing us to distinguish between what we know and what we don’t know. 
In forbidding us to go beyond the simplest description possible and it helps us to keep our distance from presumed knowledge and to understand where our theories are incomplete and are in need of improvement. However, this does not mean to say that we can use the razor as an improper weapon (that some ironically call “Occam’s chainsaw”) to destroy the theories that we do not like, maybe because they do not respond to an arbitrary definition of simplicity or do not share our metaphysical assumptions. 
Sometimes, especially in complex subjects like politics or economy, we witness reckless use of Occam’s razor that makes your skin crawl as much as the fallacies of pseudoscience, but these cases can be considered propaganda and not good scientific practice.