Whatever arises from a just situation by just steps is itself just. - Robert Nozick

There are few books that set out what a mature person can believe - someone fully grown up, I mean. Aristotle's 'Ethics', Marcus Aurelius's 'Meditations', Montaigne's 'Essays', and the essays of Samuel Johnson come to mind. Even with these, we do not simply accept everything that is said. The author's voice is never our own, exactly; the author's life is never our own. It would be disconcerting, anyway, to find that another person holds precisely our views, responds with our particular sensibility, and thinks the same things important. Still, we gain from these books, weighing and pondering ourselves in their light. These books - and also some less evidently grown-up ones, Thoreau's 'Walden' and Nietzsche's writings, for example - invite or urge us to think along with them, branching in our own directions. We are not identical with the books we read, but neither would we be the same without them.

If one machine can be used to make X (and nothing else) and another can be used to make Y, and each uses the same raw materials in the same amounts to make a unit of its product, and X is more valuable than Y, then the first machine is more valuable than the second, even if each machine contains the same raw materials and took the same amount of time to make. The first machine, having a more valuable final product, will command a higher price than the second. This may give rise to the illusion that its products are more valuable because it is more valuable. But this gets things backwards. It is more valuable because its products are.

Once a person exists, not everything compatible with his overall existence being a net plus can be done, even by those who created him. An existing person has claims, even against those whose purpose in creating him was to violate those claims.