Descartes’ Rules for the Direction of the Mind (see my blog dated June 22, 2015) gives not only the basic rules for a methodic approach of scientific problems. It contains also a number of statements that have a wider meaning; statements that have sense in the daily contact of men with each other. Some seem obvious. Nevertheless we often forget to apply them. For example, in Rule IX Descartes tells us that people are often more impressed by difficult high-flown far-fetched reasonings that they don’t completely understand than by simple transparent arguments. Knowledge, so Descartes, must not be deduced from what looks important and obscure but from what is easy and common. Isn’t it so that – my instance – a politician that uses bombastic language without content and not founded on the facts tends to have more followers than one who says the truth in a clear way?
Descartes’ words made me think of what is called Occam’s razor. Occam (or Ockham) himself didn’t use the word “razor” for his principle and he formulated it also in different words than we do today. He was a Franciscan friar who lived from about 1287-1347. The maxim that made him famous was in his words “It is vain to do with more what can be done with fewer”. Today this is read as “Entities are not to be multiplied without necessity”. For example, take the reasoning (1) “All men are mortal”- (2) “Philosophers are men” - (3) “Socrates is a philosopher” - (4) “So Socrates is mortal”. This reasoning contains the entity “philosopher”, which is superfluous here, for if we would define “philosopher”, we would get something like “a man who studies fundamental problems”. Fill in the definition in our syllogism and you’ll see that the entity “philosopher” is superfluous in this explanation why Socrates is mortal.
Sometimes Occam’s razor is considered meaning “Say it as simple as possible”. This interpretation is not correct, for arguing from several entities can be more brain breaking than a single statement with one or two entities that comprises a lot. Aristotle thought that bodies like stones fall on the ground because it’s there that their “natural place” is. However, reality appeared to be more complex and now we use complicated Newtonian suppositions and formulas for explaning gravity or, even better, Einstein’s theory of general relativity, even though Aristotle’s view was simpler.
Occam’s razor has a long history. Actually Occam was not the first one who formulated the principle. Once clearly formulated by him it had a big influence. Many scientists applied it and many philosophers referred to it. Wittgenstein, one of my favourite philosophers, said it this way: “If a sign is not necessary then it is meaningless” (Tractatus logico-philosophicus: 3.328). Or later “Occam’s Razor ... says that unnecessary elements in a symbolism mean nothing.” (5.47321).Things that we first thought to be simple can be quite complicated but Occam’s razor helps us avoid unnecessary complications. It’s not completely harmless, as we have seen, and take care of the pitfall of oversimplification of Occam’s razor, but nevertheless as a rule of thumb you can start with the idea to keep it as simple as you can and then look what it brings. It helps prevent that you’ll be deceived by people who want to impress with an air of erudition and scholarship. For as Descartes warned us in Rule XII: Learned people are often so ingenious that they find a way to be blind even in matters that are clear as such and that every simple mind understands.