This paper addresses the issue of the relationship between Ralph Johnson’s idea of dialectical tier and the critical scrutiny function in argument. We first give a concise articulation of the critical view of argument, and then probe into both the apparent similarities and deep discrepancies between the critical view of argument and Johnson’s views on the dialectical tier and manifest rationality. On that basis, we disprove the conjecture that the presence of a dialectical tier indicates that the thesis in argument (...) is critically established. However, we also urge to bridge together the critical view of argument and Johnson’s theory of argument, and thereby to make the dialectical tier critical in nature. We argue that this could be a promising proposal, and conclude with some remarks on exploring the critical dimension within our current study of argument. (shrink)