The correctness of much testimonially based belief is no more than minimally creditable to the believer.

When we speak of ordinary unqualified knowledge, my thought is that we are implicitly relativizing to the standards imposed by our evolution-derived humanity. These are standards that determine when we consider it appropriate to store beliefs just as a human being, rather than in one's capacity as an expert of one or another sort. Such stored beliefs are to be available for later use in one's own thought or in testimony to others.

It is possible to produce something that is grammatical either by chance or under the supervision of another. To be proficient in grammar, then, one must both produce what is grammatical and produce it grammatically, that is, in accord with knowledge of grammar in oneself.

When I accept someone's testimony, I am thus only a small part of the full seat of epistemic competence, which might include many others in a long chain. My own contribution might then be slight, just through the perceptual and linguistic competence involved in knowing what someone is saying or writing, etc.

If we have a better understanding of knowledge than we do of such justification or competence, then we can explain the latter through the former.

When there are conflicts of observation, when experiments cannot be replicated, scientists may then retreat to a study of the various specific observations so as to explain the conflict, in the course of which they would make use of the concept of observation, or of some specification of that concept.

The risk pertinent to a particular attempt (and to its evaluation as an attempt of its sort) is the risk that the agent will fail to attain the end constitutive of that attempt. This risk of failure is coordinate with how likely or unlikely it may be that the agent will then succeed.