I take theoretical possibility for granted: any truth can be re-conceived in myriad true ways (and infinite false ways).
But theoretical possibility is much broader than practical possibility, which is narrowed by a number of limiting factors. One of these limiting factors is social possibility. If nobody feels dissatisfaction with things as they are, many possibilities are never even glimpsed, much less entertained, explored, pursued or actualized.
Dissatisfaction and deep diasagreement is the opening up of social possibility.
Great! Now, at least, I have justification for my existence.
The real task is not stopping at disagreement, but instead linking one’s own dissatisfactions with other people’s dissatisfactions, and forming alliances abstract and deep enough to accommodate enormous diversity but practical enough to direct people’s efforts toward concrete outcomes. The alliances can (and maybe must) start with agreeing on the faults of the status quo, but it can’t stop there. It is necessary to develop positive, concrete alternatives that appeal to a large enough proportion of the population to lure them away from what they already have. It’s just like what Kuhn says about scientific revolutions.