Hypothesis

A hypothesis is a proposed explanation for a phenomenon. In the scientific method, among other things, a hypothesis should be falsifiable, meaning that, if false, it can be disproven by further observation.

As an example, based on the quality of Wikipedia articles, one could form a hypothesis that Wikipedia articles can only be edited by highly qualified professors with multiple Ph.Ds. It can be considered a hypothesis, as it it falsifiable; it can be falsified by noticing that anyone can edit Wikipedia articles, using the 'edit page' link on all pages. An experiment in this regard would be to simply click that link, edit the page, and save. If the replaced page appears, and you do not have these multiple Ph.Ds, your hypothesis is falsified, and the experiment ends.

However, it is possible and desirable to extinct hypotheses with only a thought experiment, although more prone to error, to focus resources on the most insightful physical experiments, one where there is truly some doubt. For instance, one could conclude that, given the name of the link on the pages, that there was sufficient intent to eventually make all pages editable, that it would eventually work, and not bother to do the experiment. Such a choice raises the risk that one would not discover a form asking one to declare one's education at some point in the editing process, which if it existed, might validate the hypothesis. Determining whether such a risk exists is a lot of science - the philosophy of science explores these, and more complex, questions. A naive acceptance of falsificationism is no longer a scientific viewpoint.

See Philosophiae Naturalis Principia Mathematica for Newton's position on hypotheses ("Hypotheses non fingo" : "I do not feign hypotheses").

See also Statistical hypothesis testing.