I see prior probabilities talked about often in relation to scientific studies lately. But is it really appropriate to assign a prior probability to something that is already true or false?<p>The theory&#x27;s truth or falsehood is a fact in the world that exists independently of any of our models. Does it really have a &#x27;prior probability&#x27; of being true or false? And if so is there really any sense in which we could realistically assign it one? Should we look at the history of the field or the researcher?