God"s being the best of these wouldn"t mean he is all-powerful, all-knowing, a perfectly good. The idea here is that god is a being who is the best possible being. There is no more perfect being in any possible world. What can be conceived of may vary from individual to individual. Where we can conceive of something is a fact about us as knowing subjects. What is possible doesn"t vary from one thinker to another. For something to be possible, it isn"t enough that you can conceive of its happening or that you can"t see any reason why it wouldn"t happen. God isn"t just the best being we frail human beings can conceptualize. God is supposed to be the best possible being. According to anselm, a truly perfect being wouldn"t depend for its existence on anything coningent. Also, a necessary being is more perfect than a coningent one.