Logical positivism is a way of thinking popular in the mid-20th century which attempted to make philosophy more rigorous by creating criteria for evaluating the truth or falsity of certain philosophical statements. Its main criteria for any statement is verifiability, which comes from two different sources: empirical statements, which come from science, and analytic truth, statements which are true or false by definition. Logical positivism heavily influenced philosophy of science, logic, and philosophy of language, among other areas, though today it is largely viewed as an overly simplistic approach which has been displaced by newer philosophies.

Logical positivism is an absolutist way of looking at statements and labeling them either true, false or meaningless. In modern times, this has been displaced by philosophies which view the truth or falsity of statements in a probabilistic rather than an absolute light. Logical positivists themselves had many disagreements, demonstrating that this notion of logical positivism was more a cluster of philosophies rather than any monolithic philosophical code.

A key component of logical positivism is that it rejected statements about ethics and aesthetics as being unverifiable, and therefore not a part of serious philosophical thinking. To have meaning, a given statement had to be connected to either empirical data or analytic truth. Logical positivism was a key step in connecting philosophy more closely to science, and vice versa. It continues to have influence to the present, playing a vital part in the formulation of philosophical ideas throughout the 20th century.

One of logical positivism's most salient critics was Karl Popper, who viewed meaning in terms of falsifiability rather than verifiability. Many critics of logical positivism asserted that its underlying principles themselves were not entirely verifiable or consistent, to which its proponents responded that no philosophical system can be entirely consistent in the same way certain mathematical systems can.

Later thinkers distinguished between two classifications of verifiability: "strong" and "weak" verification, the former being something being conclusively established by experience, the latter only being rendered probable by experience. Modern-day philosophers of science acknowledge that nothing can be conclusively established once and for all, and in fact all theories are only probabilistic abstractions progressively verified by experience, but never confirmed with 100% confidence.