First Questions: An Introduction to Philosophy

Philosophy asks the questions that no experiment or dictionary can close, and answers them by argument rather than by observation or authority.

An argument is a set of premises offered in support of a conclusion, which is exactly what separates reasoning from mere opinion.

A valid argument has a form that guarantees its conclusion if the premises are true; a sound argument is a valid one whose premises are in fact true.

Knowing something is more than believing it and more than happening to be right: on the classic account it is holding a true belief for good reasons.

Descartes deliberately doubts everything he can in order to find what he cannot doubt, and reaches the one belief that survives the demolition: that he is thinking.

The radical skeptic cannot be simply refuted, but the challenge can be answered and, more usefully, turned into a tool for testing which of our beliefs are actually justified.

The mind–body problem asks how conscious experience relates to the physical brain, with dualism and physicalism standing as the two great and opposed answers.

What makes you the same person as the child in your old photographs stops being obvious once body, memory, and psychological continuity are pulled apart as rival criteria.

Determinism says every event, choices included, has prior causes; compatibilism answers that a choice can still be free when it is caused in the right way — by your own uncompelled desires — so freedom and determinism need not conflict.

Consequentialism holds that an action is right in proportion to how much good it produces overall — counting everyone's welfare equally — so rightness is judged by results, not by the motive or the rule behind the act.

For Kant, an action is right only if the principle behind it — its maxim — could be willed as a universal law for everyone, and only if it treats each person as an end in themselves and never merely as a means.

For Aristotle, a virtue is a settled disposition of character to act and feel well, and each virtue sits as a mean between two vices — one of excess and one of deficiency — found by practical wisdom in each situation.

The question of life's meaning is really several questions — about purpose, about value, and about mattering — and each takes a different kind of answer.

Whether God exists is argued as a matter of evidence — from cause, design, and being in favor, and from the problem of evil against — with each argument weighed on its merits.

A just distribution can be judged by fairness, by liberty, or by need — and Rawls's veil of ignorance is one influential test for principles no one could reasonably reject.

Mill's harm principle marks the border of legitimate coercion: your liberty may be restricted only to prevent harm to others, not for your own good.