Brazenly stolen from verytallguy's comment over at ATTP. What if JFK in his moon speech had adopted the approach of many `lukewarmers' like Ridley and Tol, that future generations can probably work something out?

All great and honorable actions are accompanied with great difficulties, and both must be enterprised and overcome with answerable courage.

We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organise and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win.

It is for these reasons that we should do nothing and just wait for someone to invent an antigravity machine.