Name for various theories, including: first, the view that certainty is unattainable and that we should therefore seek and be satisfied with mere probabilities (a mild form of skepticism); secondly, the view that science can give positive probabilities to hypotheses and need not content itself with falsificationism.
These two views can be thought of as approaching the same position from different ends. In Roman Catholic doctrine, probabilism is the view that when in doubt about how we ought morally to act we may follow any reputable authority.
L Wittgenstein, Philosophical Investigations (1953), 243-315;
O R Jones, ed., The Private Language Argument (London, 1971)