How likely is the simplest explanation of something the correct one?

Question

When assuming how something is the way it is, you choose the simplest explanation. But what is the chance of this actually being the explanation? For example, say a cucumber randomly appeared on the ground. After your initial shock, you would try to figure out how it appeared without seeing it placed there. You might assume you blacked out for a second without noticing or it's a realistic dream. But how can you know the actual chance of this? There could be countless ways it could be like that (some could even include this being a fake reality, making there more ways), so is there really much chance it's what your theory is?

Answer 1

Philosophy deals with reality under the assumption that actual reality is reasonable, following observations that observed reality is most reasonable, most of the time (except for occasional unreliable reports of miraculous healing, UFO sightings and so on).

This is only possible thanks to mankind collecting and filing observations in a structured way. In the bronze age, a villager had little chance of knowing whether a caste standing on a cloud with a unicorn king was a realistic or unrealistic proposition.

If actual reality were unreasonable, such as cucumbers appearing out of nowhere regularly, philosophy would not be a useful tool.

So applying philosophy of a reasonable world to an unreasonable world does not work well.

However certain people in history have observed things that did not match their model of reality. Such as schizophrenics, people with hallucinations, but also scientists noticing signs that the earth is round, that species evolve, that traits are inherited, that sexual attraction is not always towards the opposite gender.

Given our knowledge of both perception flaws and paradigm shifts, it would seem most reasonable in case of observations that do not fit our model of reality to first question our own perceptions with the help of a psychologist, then question the validity of the world paradigms second with the help of a team of world renowned expert scientists, and only third to question the reasonability of reality itself (a very distant third) with the help of the global community of mankind.

This order seems most reasonable as given the distribution of observed perception flaws and paradigm shifts in human history.

Answer 2

The notion of a correct explanation is a difficult concept, because the question speaks to context and causality, and those are difficult to sort out because, given the main consensus, human reason is defeasible and thus fallibilistic. Thus, there is a standing issue in deciding what exactly is the "correct" explanation, and in the philosophy of science, it might be represented by the idea of underdetermination.

But the real difficulty in addressing your question is that your question asks about the nature of chance, which itself has several interpretations. Frequentism is one notion of probability. But is not the only. A brief survey of interpretations of probability reveals that the notion of "chance" has a number of metaphysical issues that affect interpret the question. This is why Occam hedged on his claim stating that simpler claims tend to be more likely for being correct but did not go so far as to say much more than that. Taken as a philosophical razor, it's just a general heuristic to hold any explanation that's highly complicated should be held suspect. It is not a probabilistic formulation that one might find in a theorem.

Answer 3

How likely is the simplest explanation of something the correct one?

We don't know. This something that depends on each specific case and may require hard work to find out, or may even be beyond our means to find out.

Reasonable people go for the simple explanation not because they believe religiously that simple explanations are necessarily true, or even just more likely true. They go for simplicity because it saves time and a simple explanation is much easier to falsify. This allows progress and is safer in the long run.

The God explanation is probably the most complicated explanation we can think of and after several millennia we still haven't been able to falsify it despite our superior logic and modern telescopes. Come back in a billion years and still nobody will have been able to falsify it and no wonder. Compare with science. Science is on the move. Progress is made all the time. And it works, and it works even when the theory is patently false like Newton's Universal Law of Gravitation.

Reasonable people start with simple explanations, and only if it becomes necessary they upgrade gradually to more complicated theories. How likely it is that even a brilliant mind would have discovered General Relativity say at the time of Newton? I think zero is the answer. So Newton was wrong as to truth but right as to methodology. Einstein proved Newton was right in this respect.