The Economics of Marriage

Richard Posner, while explaining his position on pre-emptive war, wrote here:

It would be paralyzing to suggest that we should never act unless we can quantify the expected benefits and costs of our acts (there would be very few marriages under this approach).

Exactly. We cannot quantify perfectly any expected costs and benefits; all, or nearly all, of our decisions are made under uncertainty. Courtship is shopping -- a way of acquiring information to reduce the range of uncertainty about our expectations.