Posted by: dacalu | 26 February 2012


I wanted to make a brief comment today about Ockham’s razor, or the philosophical preference for simple explanations over complex ones.   Ockham’s razor does important work and has been instrumental in the production of elegant, efficient, and productive theories.  Modern chemistry, for example, can model most everyday reactions solely on the basis of keeping track of electrons.  Previous theories postulated many different kinds of matter, many different types of forces.  No we think in terms of protons, neutrons, and electrons and electromagnetism.  (Turns out even the most complicated chemistry can be explained with fewer than 20 basic particle and 2 forces.)  Ockhams’ razor is powerful.

What William of Ockham actually said was “never multiply entities (unnecessarily).”  That is, if you can explain something using only one cause or factor, don’t add more.  And this is credited with the very successful reductionisms in modern science.

So far so good, but I want to bring up a related topic, that of infinite regress.  Many scholastic theologians (though not Ockham) subscribed to a cosmological argument for the existence of God.  They argued that every physical thing must have a cause, and that meant there must either be a first cause or an infinite regression of causes (turtles all the way down).  For most scholastics, that meant there must be a first cause, a necessarily non-physical cause, because all physical things have causes.  This uncaused cause or, as Aristotle had it, the unmoved mover was equated with God.  Ockham rejects the deductive argument against an infinite number of causes, but I think he still would have found it unappealing just because and infinite number of causes is way too many entities.  For him, an unmoved mover was far more elegant.

On the other hand, there is an anti-cosmological argument put forward by anti-theists claiming that Ockham’s razor cuts the other way.  They say that physical things explain all observed phenomena, so why should we posit an non-physical unmoved mover.  God, for them is a whole class of entities added onto the explanation.  Therefore, the argument goes, God is an inelegant and unnecessary supposition that should be eliminated.

I disagree that God gives no additional predictive power, but for the moment let us assume that were the case.  That challenge comes from the fact that the anti-theists and the scholastics both claim to be using Ockham’s razor, but they come to opposite conclusions.  Everyone gets frustrated.

I think this results from different schemes for counting entities.  Think of an engineering problem.  Do you want the solution that takes the least amount of time, the least amount of money, the least amount of space, or the fewest number of steps?  Desalinization is a great example (removing salt from water).  It’s tremendously cheap and simple to evaporate salt water and collect the moist hot air in a cooling tower.  In hot, dry environments, this can be a very effective way for a small number of people to gather drinking water.  Unfortunately it does no scale up well.  Heat input and space can be expensive.  Reverse Osmosis turns out to be a better large scale method, but it requires complex mechanisms.  Other methods, like nanofiltration, have their own strengths and weaknesses.  So the most elegant method will be different depending on how you define elegant, what you simplify and what you maximize.

The same is true in philosophy.  We cannot simply invoke simplicity (or Ockham’s razor).  We have to think about what commitments we have.  It frustrates me when anti-theists invoke Ockham’s razor as ruling out supernatural entities.  In most cases, they have chosen to start with empiricism, which requires methodological naturalism – that is to say scientists (in so far as they are scientists) can only speak meaningfully about physical (and energetic) entities.  It’s no surprise that non-physical entities are not needed to explain physical processes and, if you reduce everything to physical processes from the start, no, they won’t magically pop up.  Using science as an argument against non-physical entities is like using red goggles to disprove the existence of green lights.  It assumes the conclusion.

Let’s not let the other side off the hook, however.

First, pro-theists genuinely need to prove that the God assertion does useful work.  It’s not enough to rule out the infinite regress as implausible.  As Sherlock Holmes says, “when you have eliminated the impossible, whatever remains, however improbable, must be the truth.”  Implausibility reflects on the reasoner’s lack of imagination, not on the universe.  Those of us that do value Ockham’s razor will want some theory of God that has predictive value.

So, I’d ask all of you who are reading this to think critically about the theories you use to explain the world around you.  First, formulate them in the simplest way possible.  Second, ask how you simplify.  And third, use this not as a rock solid defense of your position, but as a way of identifying which fundamental assumptions you hold.  After all, it doesn’t do any good to minimize entities, if you can’t even identify what those entities are.


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