 A theory’s clashing with common sense is not the only way in which it can face a burden of proof. Of two theories, A and B, if A explains a range of observable phenomena more readily than B, then proponents of B will have to undertake extra labor of squaring their theory with the available evidence—and this may be the case even if B strikes people as the more intuitive theory. For example, perhaps Newtonian physics is more intuitive than Einsteinian, but there is observable data—e.g., the results of the famous solar eclipse experiments of 1919—that the latter theory is much better equipped to explain.