How did logical positivism use the verifiability principle to test statements?

Logical positivism utilized the verifiability principle as a criterion to determine the meaningfulness of statements. According to this doctrine, a statement is considered meaningful only if it is either tautological (true by definition) or empirically verifiable through observation.12

To test a statement that purports to describe a matter of fact, logical positivists asked what specific empirical conditions would count for or against its truth. If no observable evidence could be relevant to determining its truth or falsity, the statement was deemed "assertorically meaningless"—a category they applied to most metaphysical, ethical, and religious claims.312

The application of this principle evolved over time:
* Early View: Initially, the requirement was strict, demanding that a statement be conclusively verifiable through a finite set of observation reports.13
* Later View: Recognizing the limitations of strict verification, later proponents required only that a statement be supported, made evident, or rendered probable by relevant empirical observations.13

Ultimately, the positivists used this principle as a tool to challenge the significance of metaphysical systems, arguing that such claims often lacked any connection to observable reality.3