difference between correspondences in our experience and similarities

"we have given an account of metaphorical grounding in terms of systematic correspondences in our experience, for example, being dominant in a fight and being physically up. But there is a difference between correspondences in our experience and similarities, since the correspondence need not be based on any similarity. On the basis of such correspondences in our experience, we can give an account of the range of possible metaphors. The weak homonymy position has no predictive power at all and seeks none. It simply tries to provide an after-the-fact account of what similarities there are. Thus, in the cases where similarities can be found, the weak homonymy position still gives no account of why just those similarities should be there." (#60 1996)