If argument is to provide sufficient reasons for accepting or rejecting a claim, then why is disagreement possible?
Agreement is valued everywhere: it sounds friendlier and builds communities of like-minded individuals. Valuing unanimity, we may accept tradition without asking too many questions. Agreement is easy, and invites acceptance of ideas without much thought, whereas disagreement is criticism, involving a great deal of creativity and willingness to go against the grain, and more often than not produces conflict. Kuhn advocated agreement in his ‘normal science’, knowing that science and a measure of dogmatism occur naturally: there are far worse traditions than science. There is an alternative to this admittedly irrationalist solution, namely a rational justification: as Bacon said, by far the best proof is experience. The problem then becomes how does experience justify theory?
This formulation of the problem of justification is problematic itself, for our justifications are always insufficient: in arguments, the dissenter objects to an assumed premise, stirring up controversy all over again. And how can one object to the dissenter? By appealing to the assumed premise? I think not. For instance, after agreeing on the nature of our collective experience, how does this then justify any theory over another? There are too many problems left: the problem of induction, underdetermination, etc., and there are many competing solutions.
… for instance, a scientist might object to an outcome of a crucial experiment: if the outcome of a crucial experiment and a theory contradict one another, then the outcome of the crucial experiment cannot compel a scientist to reject a theory and the theory cannot compel a scientist to reject the outcome of a crucial experiment. Experience and theory both suffer under the problem of meta-underdetermination: either the experience or the theory is wrong–or both.In other words, why should the scientist assume the meta-theory (M1) that experience is a reliable way to sort out true from false theories and not assume the meta-theory (M2) that theory is a reliable way to sort out true from false experience? All that can be determined is that the two contradict one another; however, even this may not be the case, for experience is theory-laden. Furthermore, experience and a theory that appear to contradict one another may in fact exist coherently if an auxiliary hypothesis is adopted, calling their very incompatibility into question.
Therefore, argument does not, and cannot, compel one to accept a proposal, at least not in its original sense.One solution is to modify the role of argument so that it is now designed to provide insufficient, but compelling reasons. This modification has weakened the role of argument: why one finds the subjective state of certitude of merit after it has ceased to guarantee the truth, I cannot say.
The new problem is as follows: when two people mutually agree on all premises, there is no controversy. Yet, all that we have established is agreement, not the truth of the premises. From here, we are once again forced to deal with Fries’ Trilemma.