Occam’s razor, Ockham’s razor, or Ocham’s razor also known as the principle of parsimony or the law of parsimony, is the problem-solving principle that “entities should not be multiplied beyond necessity”. if you have two competing ideas to explain the same phenomenon, you should prefer the simpler one.
Occam’s Razor is attributed to English Franciscan friar William of Ockham (c. 1287–1347), a scholastic philosopher and theologian, although he never used these words. He stated that “plurality should not be posited without necessity.”
Scientists must use the simplest means of arriving at their results and exclude everything not perceived by the senses.Ernst Mach – a Moravian-born Austrian physicist and philosopher, who contributed to the physics of shock waves
Others before Ockham had worked using this same principle. Durandus of Saint-Pourçain, a French Dominican theologian and philosopher, Nicole d’Oresme, a 14th-century French physicist, as did Galileo later, in defending the simplest hypothesis of the heavens. Ockham, however, mentioned the principle so frequently and employed it so “sharply” that it was called “Occam’s razor”.
When you hear hoofbeats, think of horses not zebras.Theodore Woodward – American medical researcher in the field of medicine at the University of Maryland, Baltimore
However, it is essential to realize that Occam’s razor is more of a logical guideline than a law. It doesn’t prescribe oversimplification, and if a more complex theory is available that better explains the facts, then the more complex approach should be preferred. As is always the case with science, empirical evidence should win out.
If a thing can be done adequately by means of one, it is superfluous to do it by means of several; for we observe that nature does not employ two instruments [if] one suffices.Thomas Aquinas – Italian Dominican friar and priest, who was an immensely influential philosopher, theologian, and jurist
Francis Crick, a co-discoverer of the structure of DNA, warned that the “simplicity and elegance” of Occam’s razor wasn’t well suited to the messy world of biology. Darwinian evolution by natural selection, for example, is a far more complex theory than just saying all animals are the product of a divine creator, but ultimately, it fits the facts as we know them far better.
Whenever possible, substitute constructions out of known entities for inferences to unknown entities.Bertrand Russell – a British philosopher, logician, and public intellectual
The phrase Occam’s razor did not appear until a few centuries after William of Ockham’s death in 1347. Libert Froidmont, theologian and scientist, in his “On Christian Philosophy of the Soul”, takes credit for the phrase, speaking of “novacula occami”.
Any more complex theory might still possibly be true. A study of the predictive validity of Occam’s razor found 32 published papers that included 97 comparisons of economic forecasts from simple and complex forecasting methods. None of the papers provided a balance of evidence that the complexity of the method improved forecast accuracy. In the 25 papers with quantitative comparisons, complexity increased forecast errors by an average of 27 percent.
A hypothesis with fewer adjustable parameters will automatically have an enhanced posterior probability, due to the fact that the predictions it makes are sharpWilliam H. Jefferys (an American astronomer) and James O. Berger (American statistician)