By synthesizing the argumentation theory of new rhetoric with research on heuristics and motivated reasoning, we develop a conceptual view of argumentation based on reasoning motivations that sheds new light on the morality of decision-making. Accordingly, we propose that reasoning in eristic argumentation is motivated by psychological (e.g., anxiety reduction) or material (e.g., vested interests) gains that do not depend on resolving the problem in question truthfully. Contrary to heuristic argumentation, in which disputants genuinely argue to reach a practically rational (...) solution, eristic argumentation aims to defeat the counterparty rather than seeking a reasonable solution. Eristic argumentation is susceptible to arbitrariness and power abuses; therefore, it is inappropriate for making moral judgments with the exception of judgments concerning moral taboos, which are closed to argumentation by their nature. Eristic argumentation is also problematic for strategic and entrepreneurial decision-making because it impedes the search for the right heuristic under uncertainty as an ecologically rational choice. However, our theoretical view emphasizes that under extreme uncertainty, where heuristic solutions are as fallible as any guesses, pretense reasoning by eristic argumentation may be instrumental for its adaptive benefits. Expanding the concept of eristic argumentation based on reasoning motivations opens a new path for studying the psychology of reasoning in connection to morality and decision-making under uncertainty. We discuss the implications of our theoretical view to relevant research streams, including ethical, strategic and entrepreneurial decision-making. (shrink)