Occam's Razor, or more properly "“Ockham's Razor”, is named after the late medieval theologian William of Ockham. Occam's razor is the idea that simpler explanations are more likely to be true than complex ones. William of Ockham (c. 1287–1347) is, along with Thomas Aquinas and John Duns Scotus, among the most prominent figures in the history of philosophy during the High Middle Ages. He is probably best known today for his espousal of metaphysical nominalism.
How Ockham used his razor Edit
Ockham's Razor, in the senses in which it can be found in Ockham himself, never allows us to deny putative entities; at best it allows us to refrain from positing them in the absence of known compelling reasons for doing so. In part, this is because human beings can never be sure they know what is and what is not “beyond necessity”; the necessities are not always clear to us. But even if we did know them, Ockham would still not allow that his Razor allows us to deny entities that are unnecessary. For Ockham, the only truly necessary entity is God; everything else, the whole of creation, is radically contingent through and through. In short, Ockham does not accept the Principle of Sufficient Reason.
Nevertheless, we do, according to Ockham, sometimes have sufficient methodological grounds for positively affirming the existence of certain things. Ockham acknowledges three sources for such grounds (three sources of positive knowledge). As he says in Sent. I, dist. 30, q. 1: “For nothing ought to be posited without a reason given, unless it is self-evident (literally, known through itself) or known by experience or proved by the authority of Sacred Scripture.”
How the razor is used today Edit
Evidently, then, the principle itself is poorly named when it is instead taken to mean "one may prudently deny the existence of putative entities beyond what the datum makes necessary in itself" and in that form is used to deny the existence of God, as this goes far beyond Ockham's own usage of the Razor and even contravenes one of the three exceptions he posited to the Razor (namely, "the authority of Sacred Scripture"). This usage is more indicative of the atheistic philosopher Betrand Russel's interpretation of the proper usage of the "razor", rather than Ockham's own. Modern Atheists, of course see no reason for saying that God (Far Right Religious POV) or even God (Liberal Christianity Viewpoint) are necessary and see no reason for treating the Bible differently from other Mythology.
Suppose that there are two possible explanations for an event. For sake of argument, suppose each premise has a 50/50 chance of being true. One explanation requires only one premise to be true, so therefore, the chance that this explanation is true is 50%, out of all possibilities, regardless of if the event happened or not. Suppose that there is a second explanation that requires explanation 1 to be false, and requires 3 other premises to be true. The chance that this explanation is true is 6.25%
When calculated, the chance that option 1 is the correct explanation is about 89%.
- Occam's razor Occam's razor explained very much more simply