This paper is a case study. After formulating three norms for critical assessment of argumentation (section 1), I give a brief overview of Galileo’s argumentative strategy in his Dialogue and present his argument for the cause of the tides, which appears as an argument by analogy (section 2). I then discuss possible reconstructions of this argumentation, with one particular suggestion in detail. These arguments seem to fall short, given the aforementioned set of norms (section 3). This leads to my own (...) proposal of Galileo’s argument. I defend this proposal and it’s general idea - that is, the argument’s pattern. It will be classified as ‘interventionist’ and useful regarding the goals of critical assessment (section 4). Finally, I suggest that the pattern of argument is applicable to other cases and useful for applied theory of science (section 5). (shrink)