  The acceptance of probable hypotheses as the best available was a significant revision of a model of human knowledge, originally derived from Aristotle, according to which genuine knowledge must achieve the degree of certainty that is provided by intuition and demonstration (Clarke 2011).  While other natural philosophers, even at the conclusion of the seventeenth century, refused to classify explanations of natural phenomena as knowledge, because they were uncertain, Regius had accepted in mid-century that such uncertainty is inevitable except in the case of divine revelation. “Although, apart from divine revelation, there is no apodictic certainty about things that exist outside our mind, but only moral or probable and likely certainty, that is still sufficient to perform adequately and to control all the activities of human life, since nothing more is required for them apart from moral or probable truth or the certainty and likelihood of knowledge” (Regius 1654, 351).