(1) According to the Theory of Reflection and Knowability , News communicators can promise the news to be true.

(2) In epistemology, knowability and agnosticism have been the focus of debate of philosophers.

(3) Things with knowability and the exhaustiveness of knowing the things with knowability are two different matters.

(4) The knowability of the execution situation of event-based prospective memory(EBPM) was manipulated and its effect on EBPM processing was examined.

(5) Knowability is the objective nature of all the things in the universe, but not all the things with knowability can be transformed into the knowable things in reality.

(6) This paper is to make an analysis of the knowability of things and the non-exhaustiveness of knowability so that it can lead to further discussion about this subject.

(7) Improving measures, which has take the actuality into account, to knowability are suggested for existing problem and verify the feasibility of study strategy.