Today, few would deny the central importance of science to our lives, but not many of the general public would be able to give a good account of what science is. To most, the word probably brings to mind not science itself, but the fruits of science — the pervasive complex of technology that has transformed all of our lives. However, science might also be thought to include the vast body of knowledge we have accumulated about the natural world. There are still mysteries, and there always will be mysteries, but the fact is that, by and large, we understand how nature works.

We don't really know what the scientific method is.

But science is even more than that. If one asks a scientist the question “what is science?”, the answer will almost surely be that science is a process, a way of examining the natural world and discovering important truths about it. In short, the essence of science is the scientific method.

That stirring description suffers from an important shortcoming: we don't really know what the scientific method is. There have been many attempts at formulating a general theory of how science works, or at least how it ought to work, starting with Sir Francis Bacon. His idea, that science proceeds through the collection of observations without prejudice, has been rejected by all serious thinkers. Everything about the way we do science — the language, the instruments, the methods we use — depends on clear presuppositions about how the world works. Modern science is full of things that cannot even be observed at all. At the most fundamental level, it is impossible to observe nature without having some reason to choose what is worth observing and what is not worth observing. Once one makes that elementary choice, Bacon has been left behind.

Science, it turns out, is whatever scientists do. That, of course, is not an adequate philosophical description, but it may be the best we can do.