In the absence of empirical confirmation, scientists may judge a theory's chances of being viable based on a wide range of arguments. This chapter argues that such arguments can differ substantially with regard to their structural similarity to empirical confirmation. Arguments that resemble empirical confirmation in a number of crucial respects provide a better basis for reliable judgment and can, in a Bayesian sense, amount to significant non-empirical confirmation. It is shown that three kinds of non-empirical confirmation that have been specified in earlier work do satisfy those conditions.