 Duns Scotus denied the necessity of the present and thought that it need not be incoherent to consider actually false propositions as possible at the present instant. That you are standing does not exclude that you are running is a logical possibility, it only excludes actual running. This kind of thinking has been found to reflect a major change in how alethic modalities are conceived. After Scotus, many thinkers thought of modalities as related to conceivability and logic, and not so much as based on being in someone’s power, or true at some time or other. That is, the possibility of a proposition became taken to be an issue unrelated to the flow of time.