4. The grounds of probability are two: conformity with our own experience, or the testimony of others'
experience.
Probability then, being to supply the defect of our knowledge and to guide us where that fails, is
always conversant about propositions whereof we have no certainty, but only some inducements to receive them
for true. The grounds of it are, in short, these two following:--
First, The conformity of anything with our own knowledge, observation, and experience.
Secondly, The testimony of others, vouching their observation and experience. In the testimony of others is to be
considered: 1. The number. 2. The integrity. 3. The skill of the witnesses. 4. The design of the author, where it is a
testimony out of a book cited. 5. The consistency of the parts, and circumstances of the relation. 6. Contrary
testimonies.