The "validity" such an argument has(if that is the right word) is presumptive and provisional in nature.5 It is frail, andsubject to default.Even so, such presumptively based arguments can be very useful and important in cases where action must be taken, but firm evidence is not presently available. Examples would be in planning, where the future holds many uncertainties,or in practical deliberation, where prudent action often requires acting on provisional hunches and guesswork, always subject to revision, as better informationcomes in.

According to the pragma-dialectical theory of vanEemeren and Grootendorst, Blair noted, "sufficiency is a function of appropriatelymeeting the critics' challenges to premises and inferences" (p. 3 32) . Blair alsonoted that this means that an argument can rightly be said to be sufficient for itsconclusion in this sense when it meets its burden of proof3 relying on "what maybe presumed without or accepted without further question" (p. 333)

What has been shown, instead, is that each of these types of argumentationis tentative and inconclusive-open to critical questioning-while still being strongenough, in many cases, to have some degree of bindingness or logical correctnessin transferring acceptance from the premises to the conclusion. However, thebindingness is not of an unconditional or absolute kind-like deductive validity.Instead, it is a kind of tentative or provisional acceptance that is involved, (i.e.,"Now I have accepted these premises, I am bound to tentatively accept the conclusion, for the sake of argument or discussion,