A man can surely do what he wills to do, but he cannot determine what he wills.

But this was that view of human destiny which she had most passionately hated and rejected: the view that man was ever to be drawn by some vision of the unattainable shining ahead, doomed ever to aspire, but not to achieve. Her life and her values could not bring her to that, she thought; she had never found beauty in longing for the impossible and had never found the possible to be beyond her reach.

That which you call your soul or spirit is your consciousness, and that which you call 'free will' is your mind's freedom to think or not, the only will you have, your only freedom, the choice that controls all the choices you make and determines your life and your character.

No one's happiness but my own is in my power to achieve or to destroy.

It is my will which chooses, and the choice of my will is the only edict I must respect.

whose steps were a restless substitute for flight.

Man has no automatic code of survival. His particular distinction from all other living species is the necessity to act in the face of alternatives by means of volitional choice. He has no automatic knowledge of what is good for him or evil, what values his life depends on, what course of action it requires...Man must obtain his knowledge and choose his actions by a process of thinking, which nature will not force him to perform.

And, after all, you've got to live." "Not that way," said Roark.

You cannot predict the future.

Yet if there really were a complete unified theory, it would also presumably determine our actions—so the theory itself would determine the outcome of our search for it! And why should it determine that we come to the right conclusions from the evidence? Might it not equally well determine that we draw the wrong conclusion? Or no conclusion at all?

According to Feynman, a system has not just one history but every possible history.

Do the laws governing the universe allow us to predict exactly what is going to happen to us in the future? The short answer is no, and yes. In principle, the laws allow us to predict the future. But in practice the calculations are often too difficult.