Occam's Razor

Written by Studio AM.

When two explanations both fit the facts, which should you believe? A principle known as Occam's razor offers a rule of thumb: prefer the one that assumes the least. If a simpler account and a more complicated one explain the same evidence equally well, the simpler is usually the better bet.

The razor does not claim that the world is always simple. Reality is often tangled, and the plainest story is sometimes wrong. The narrower advice is this: do not multiply assumptions without need. An extra assumption should do useful explanatory work. If removing it changes nothing about how well the account fits the evidence, there may be no reason to keep it.

Consider a light that will not turn on. One explanation is a dead bulb. Another is a fault in the town's power grid combined with a coincidental failure of your neighbor's line and a problem with your switch. Both accounts could include a reason for the darkness, but the second adds events for which no evidence has been given. Checking whether the bulb works is a reasonable starting point. Other observations, such as nearby lights failing too, could support a different account.

Used well, the razor is a guide to allocating attention, not a substitute for evidence. It tells you where to look first and which added assumptions need support, not which is finally true. When new facts arrive, the simplest explanation must yield to them like any other. The razor guides the search; it does not end it.

Questions

Choose an answer. The explanation appears after you answer.

  1. Question 1 of 4

    What does Occam's razor advise, according to the passage?

  2. Question 2 of 4

    In the example of the light, which is the simpler explanation?

  3. Question 3 of 4

    Why would evidence that nearby lights had also failed matter?

  4. Question 4 of 4

    What does 'multiply' mean in this passage?

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