Empiricism, rationalism, skepticism from "summary" of The Oxford Companion to Philosophy by Ted Honderich

The empiricists emphasize a form of inductive reasoning, deriving general principles from particular experiences. By contrast, the rationalists argue for an approach based on deduction, arguing that we can draw valid conclusions from simple logic.

Empiricism is the belief that all knowledge comes from experience and evidence through observation or experimentation. It stands in contrast to rationalism, which emphasizes human reason as the primary source of knowledge.

Empiricism, rationalism, and skepticism each provide helpful tools for analyzing particular problems — and sometimes seemingly contradictory insights when taken together. Philosophers often stress how valuable it can be to entertain different points of view to gain a more comprehensive understanding.

Some philosophers have advocated for a combination (or “synthesis”) of empiricism and rationalism in their theories; others champion one philosophy over another. This debate has gone on for centuries and still continues today.

Skepticism is the practice of doubting the validity of claims and commonly accepted beliefs. It has its origins in ancient Greece and can be used to challenge both standard things like scientific ideas and deeper philosophical theories.

For the skeptic, any form of certainty is impossible; claims are either only provisionally true, at best, or simply false. This does not mean that skepticism leads to nihilism, however! There can be value in questioning assumptions and searching for better answers.