Explanatory Virtues

When we recognize these theoretical virtues, we can use them as criteria to judge between competing hypotheses, to determine which is the best explanation for whatever we’re trying to explain. Sometimes, there won’t be a clear winner, and we can’t draw any firm conclusion about which hypothesis is the best explanation. But in many cases, one hypothesis will be clearly better than its rivals, exhibiting many theoretical virtues to a much greater degree than any alternative explanation we can think of. In cases like that, we’re justified in making an inference to the best explanation—that is, we can reasonably conclude that the winning explanation is probably true.

We can use this method of reasoning to evaluate scientific explanations, historical hypotheses, philosophical theories, or even entire worldviews. Inference to the best explanation is used by scientists, historians, philosophers, and—often unknowingly—by ordinary people in everyday life. Unlike formal logic, inference to the best explanation wasn’t invented by philosophers, nor is it the exclusive craft of highly trained thinkers. It’s really just a way of clarifying commonsense principles of reasoning that we all use every day. We intuitively understand that simple, unified, elegant explanations are better—and more likely to be true, in general—than complicated, disjointed, messy ones. So, the method of inference to the best explanation is just a way of recognizing and refining these commonsense, intuitive criteria we already use without even realizing it.