A supposition; a proposition or principle which is supposed or taken for granted, in order to draw a conclusion or inference for proof of the point in question; something not proved, but assumed for the purpose of argument, or to account for a fact or an occurrence; as, the hypothesis that head winds detain an overdue steamer.
A tentative theory or supposition provisionally adopted to explain certain facts, and to guide in the investigation of others; hence, frequently called a working hypothesis.
The word 'belief' is a difficult thing for me. I don't believe. I must have a reason for a certain hypothesis. Either I know a thing, and then I know it - I don't need to believe it. Carl Jung
There are two possible outcomes: if the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery. Enrico Fermi
A fact is a simple statement that everyone believes. It is innocent, unless found guilty. A hypothesis is a novel suggestion that no one wants to believe. It is guilty, until found effective. Edward Teller
The only relevant test of the validity of a hypothesis is comparison of prediction with experience. Milton Friedman
If I were to awaken after having slept for a thousand years, my first question would be: Has the Riemann hypothesis been proven? David Hilbert