Sun
Earth and Space

Values in science and Occam's razor

Physics Narrative for 11-14 Supporting Physics Teaching

Occam's razor: simplicity is a guiding principle when constructing theories

The important point about the photographic evidence provided by a camera pointed at the Pole star is that we cannot decide between the two possible explanations. Both fit with the evidence.

We choose to believe the explanation that the Earth on which the camera is fixed is turning. Why? Because one of the values that scientists work with is parsimony, to put it in simple language, the KISS (keep it simple stupid) principle.

If you were to take the first explanation you'd have to explain why all the stars are turning around one point. That would require another theory.

William of Occam, a medieval philosopher, summarised the principle in what is commonly known as Occam's razor: That you should never multiply the entities beyond those required for the explanation.

This value lies at the heart of science which (nearly!) always looks for the simplest explanation possible.

IOP DOMAINS Physics CPD programme

New videos on forces

Our first collection of videos gives teachers and coaches of physics a preview of the training we offer ahead of this term's live support sessions.

Find out more