Occam’s Razor (also spelled Ockham’s Razor) cuts through complexity with a pragmatic approach. The philosophical maxim “Numquam ponenda est pluralitas sine necessitate”, written by the 14th century Franciscan friar William of Ockham, translates to “Plurality should never be posited without necessity”. In other words, all things being equal, simplicity is best.
So is it really true? Is the simplest explanation usually the best?
Not exactly. Ockham never said that complexity is inherently inferior to simplicity, nor did he say that complex explanations are inherently wrong. Complex scientific questions often require complex answers, and that’s not at odds with Occam’s razor. The principle simply states that unnecessary complexity is, well, unnecessary.
“Occam’s razor is to find the simplest solution that works”, Johnjoe McFadden (opens in a new tab)professor at the University of Surrey in the UK and author of the book “Life is Simple: How Occam’s Razor Unleashes Science and Shapes the Universe (opens in a new tab)” (Basic Books, 2021), Live Science said in an email. “It never fails as long as you remember the necessity clause.”
Ockham was not the first (opens in a new tab) promote simplicity. Aristotle held that “the most limited, if adequate, is always preferable”, and Ptolemy considered it better “to explain phenomena by the simplest possible hypothesis”. Some three centuries after the genesis of Occam’s razor, Isaac Newton declared that “we should only admit for natural things causes that are both true and sufficient to explain their appearances”. About 200 years later, Albert Einstein would agree that “everything should be made as simple as possible, but not simpler” (which is, in fact, a simplification of his original quote (opens in a new tab)).
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When used correctly, Occam’s razor works. If two computer programs perform the same task, the one that contains the least code is necessarily the most efficient. The simplest medical diagnosis is usually correct; hospital interns are often taught to think of horses, not zebras, when they hear hoofbeats. An involvement of the second law of thermodynamics (disorder increases for any spontaneous process) is that these processes always consume as little energy as possible.
“Copernicus proposed the heliocentric model of the solar system solely on the basis that it was simpler,” McFadden said. “The existence of a single Higgs boson was the simplest solution to the equations of particle physics. Between these points are a thousand scientific advances that depended on simplicity.”
When misused, however, Occam’s razor can become a blunt instrument of overgeneralization. Principle does not mean, for example, that we blindly follow the simplest theory, whether good or bad. “Very often the simplest assumption is too simple,” Elliot sober (opens in a new tab)professor of philosophy at the University of Wisconsin-Madison and author of the book “Ockham’s Razors: User’s Manual” (opens in a new tab) (Cambridge University Press, 2015), Live Science said in an email. “The simplicity of a hypothesis is one consideration, among others, that is relevant in assessing whether a hypothesis is true.”
When it comes to data science, Occam’s razor may cause more problems than it solves. In this case, “the simplest approach is usually wrong,” said Pedro Domingues (opens in a new tab), professor emeritus of computer science and engineering at the University of Washington in Seattle. When Domingos investigated the applicability of Occam’s Razor to machine learning in the early 2000s, he discovered that a more simple (opens in a new tab) model (opens in a new tab) is superior to a complex only if it is equally good at predicting new data.
“As modern machine learning has shown time and time again – in model sets, deep learning, etc. – it’s usually the more complex approach that is correct,” Domingos told Live. Science in an email.” And that’s no surprise; the phenomena we model are almost always more complex than the models, and the closer we get to their true complexity, the more accurate the models.”
Still, Occam’s razor remains a useful tool for cutting the fat off of voluminous assumptions, at least in our day-to-day lives. “The universe is a complicated place, but it’s sometimes made more complicated by the invention of complicated explanations that suit a particular ideology, philosophy, or political persuasion,” McFadden said. “Occam’s razor tells you to forget all about it.”