Ideal Theory and "Ought Implies Can"

When we can’t live up to the ultimate standards of morality, how can moral theory give us guidance? We can distinguish between ideal and non-ideal theory to see that there are different versions of the voluntarist constraint, ‘ought implies can.’ Ideal moral theory identifies the best standard, so its demands are constrained by one version. Non-ideal theory tells us what to do given our psychological and motivational shortcomings and so is constrained by others. Moral theory can now both provide an ultimate standard and give us guidance; this view also gives us new insights into demandingness and blame.