Two Kinds of Strategies

Suppose I need to decide whether to go off to fight for a cause in which I deeply believe, or stay home with a family that needs me and that I deeply love. What should I do? My friends say I should determine the possible outcomes of the two proposed courses of action, assign probabilities and numerical utilities to each possibility, multiply through, and then choose whichever alternative has the highest number.

My friends are wrong. Their proposal would be plausible in games of chance where information on probabilities and monetarily denominated utilities is readily available. In the present case, however, I can only guess at the possible outcomes of either course of action. Neither do I know their probabilities. Nor do I know how to gauge their utilities. The strategy of maximizing expected utility is out of the question, for employing it requires information I do not have.

Nevertheless, my friends have not given up trying to help, so they point out that I could simulate the process of maximizing expected utility by assuming a set of possible outcomes, estimating their probabilities, and then making educated guesses about how much utility they would have. I could indeed do this, but I decide not to, for it occurs to me that I have no reason to trust the formula for maximizing expected utility when I have nothing but question marks to plug into it.