Falsifiability

The Falsification Principle, proposed by Karl Popper, is a way of demarcating science from non-science. It suggests that for a theory to be considered scientific it must be able to be tested and conceivably proven false.
For example, the hypothesis that “all swans are white,” can be falsified by observing a black swan.
For Popper, science should attempt to disprove a theory, rather than attempt to continually support theoretical hypotheses.

Karl Popper argued that science would best progress using Deductive Reasoning (as opposed to inductive reasoning) as its primary emphasis, known as critical rationalism.