ABSTRACT
Locke's account of the grounds of assent or probability should be read with recognition of his concern with three things: the programme of 'natural history', the status of speculative hypotheses and the status of religious authority and faith. He began with two main distinctions. The first is between, on the one hand, 'the conformity of any thing with our Knowledge, Observation and Experience' and, on the other hand, the 'Testimony of others'v'" The second distinguishes propositions concerning particular 'matters of fact' falling within human experience and so capable of human testimony, from propositions concerning what lies 'beyond the discovery of the senses', and so beyond the scope of human testimony.':"
The probability of 'particular matter of fact' depends on the 'certainty of observations', and the 'frequency and constancy of Experience', both of ourselves and others.!" Although Locke concentrated on the relevance of general experience and report to judgements about particulars, what he said evidently applies also to generalizations. Thus the highest 'degree' of probability is when the general consent of others concurs with the subject's constant experience: 'such are all the stated Constitutions and Properties of bodies, and the regular proceedings of Causes and Effects in the ordinary course of Nature';':" The second 'degree' is when experience and testimony suggest that a thing is for the most part SO.122 The third, when unsuspected witnesses report, without contradiction, something which experience allows might as well have been so as not.':" Finally, it can happen that 'the reports of History and Witnesses clash with the ordinary course of Nature, or with one another'. The probability 'rises and falls, according as those two foundations of Credibility ... favour or contradict it'. Here, he says, there are no 'precise rules' .124
