Another consideration in favor of the break-even heuristic might be something like the following (it’s a development of my parenthetical under point three in my previous post:
Suppose you were just icy-cold about death, utterly indifferent to just how much longer you would live from the moment of your decision onward. Suppose you regard death as nothing other than the cessation of experience, a permanent zero on the scale, and a period you no more dread than you regret the nonexistence before your birth. What rational decision procedure might you follow in deciding whether or not to accept the coin-flip? Well, what you could do would simply be to survey all the things in prospect in your potential future life that give you pain. If the quantity of pleasure is greater than that of pain — deprivations of good or normal things — then it would make sense to simply decline the coin-flip and live out your life. If they pains and pleasures were exactly equal, then you would be indifferent between the coin flip and continuation. If the scale tipped into more pain than pleasure, then the coin flip becomes a desirable gamble, because it represents an opportunity for a better life than you could have just leading onward.
Thus the even probability really does in some sense the break-even point between that at which life is and is not mostly suffering.
Of course if you do fear death — and most people do — then you would need a much heavier burden of suffering over good things in life before you would be willing to accept the fair-coin gamble. But that of course makes the test of someone’s being willing to accept that fair-coin gamble all the more compelling as evidence that her life is mostly suffering.