hypothesis

[haiˈpɔθisis]
[C] an idea or explanation of sth that is based on a few known facts but that has not yet been proved to be true or correct:
to formulate / confirm a hypothesis
◆ a hypothesis about the function of dreams
◆ There is little evidence to support these hypotheses.
[U] guesses and ideas that are not based on certain knowledge
Synonym: SPECULATION
It would be pointless to engage in hypothesis before we have the facts.