Occam's Razor - The simplest explanation is usually correct
When choosing between multiple explanations
Also known as: “The law of parsimony”; “The simplest explanation is usually the right one”; “Ockham's razor”
What Does “Occam's Razor - The simplest explanation is usually correct” Mean?
Among competing explanations, the one requiring fewest assumptions is usually right. Don't multiply entities beyond necessity. Simple explanations are more likely true than complex conspiracies.
Origin and History
The principle is named after William of Ockham, a 14th-century English friar and philosopher who often argued from parsimony. The famous Latin wording 'entities should not be multiplied beyond necessity' does not appear in his surviving works; it was coined later (it is usually traced to John Punch in 1639). Strictly, the razor does not say simple explanations are true - it says that, among explanations that fit the evidence equally well, you should prefer the one that needs the fewest assumptions.
Examples
- Medicine: 'When you hear hoofbeats, think horses, not zebras' - check common causes before rare ones.
- IT support: if the screen is black, check whether it is plugged in before suspecting a broken graphics card.
- Everyday life: a friend is late - traffic is a better first guess than an elaborate scheme.
- Science: a model with fewer free parameters is preferred if it explains the data as well as a complex one.
What Happens When You Break It
Ignoring Occam's Razor leads to overcomplicated theories, conspiracy thinking, wasted effort on unlikely explanations, and missing obvious truths.
Benefits of Following This Rule
Applying Occam's Razor finds truth faster, avoids overthinking, simplifies problem-solving, identifies likely explanations, and prevents conspiracy thinking.
Frequently Asked Questions
What is the rule called where the simplest explanation is usually correct?
It is called Occam's (or Ockham's) razor, also known as the law of parsimony.
Did Sherlock Holmes say the simplest explanation is correct?
No. Holmes's maxim is different: 'when you have eliminated the impossible, whatever remains, however improbable, must be the truth' (The Sign of the Four). That is about elimination, not simplicity.
Is the simplest explanation always right?
No. Occam's razor is a rule of thumb for choosing what to test first. Reality is sometimes complicated, and evidence always beats simplicity.