A manufacturer of lipstick may well make a greater fortune than a manufacturer of microscopes—even though it can be rationally demonstrated that microscopes are scientifically more valuable than lipstick. But—valuable to whom?

A microscope is of no value to a little stenographer struggling to make a living; a lipstick is; a lipstick, to her, may mean the difference between self-confidence and self-doubt, between glamour and drudgery.

This does not mean, however, that the values ruling a free market are subjective. If the stenographer spends all her money on cosmetics and has none left to pay for the use of a microscope (for a visit to the doctor) when she needs it, she learns a better method of budgeting her income; the free market serves as her teacher: she has no way to penalize others for her mistakes. If she budgets rationally, the microscope is always available to serve her own specific needs and no more, as far as she is concerned: she is not taxed to support an entire hospital, a research laboratory, or a space ship’s journey to the moon. Within her own productive power, she does pay a part of the cost of scientific achievements, when and as she needs them. She has no “social duty,” her own life is her only responsibility—and the only thing that a capitalist system requires of her is the thing that nature requires: rationality, i.e., that she live and act to the best of her own judgment.

- Ayn Rand. Capitalism: The Unknown Ideal (1966).