An important change in contemporary imagination research is to approach the problem of imagination from the perspective of modal epistemology.The response to the three questions involved is that,first,although in most cases imagination requires the aid of images,there can be non-image imaginations.Second,to the CP thesis,"conceivability implies possibility",it is necessary to add a condition of"needing to be a sufficient reason"to Chalmers's"ideal positive conceivability".Moreover,since the role of CP thesis is similar to that of"hypothesis",it seems that it can be classified as hypothesis,and its main significance is only to enrich the category of hypothesis and draw attention to the role of imagination in hypothesis.Third,Williamson's assertion that"metaphysical modal epistemology is a special case of counterfactual conditional epistemology"is acceptable,but his view that counterfactual conditional sentence knowledge is a third type of knowledge alongside a priori and empirical knowledge may not be true.