This paper provides a case study for the use of syllogistic reconstructions in the commentaries on Plato by the fifth-century commentator Proclus. The paper discusses Proclus’ reconstruction of the argument about the range of the Forms in Plato’s Parmenides (130b–e). In his commentary on this dialogue, Proclus reports a syllogistic reconstruction of the argument proposed by some of his predecessors. In this reconstruction, the argument as a whole is interpreted as a straightforward attack on the existence of Forms, while the different premises of the hypothetical syllogism represent the respective positions of Parmenides and Socrates in the discussion. For Proclus, however, the argument about the range of Forms is not meant to be critical of the Forms, but rather provides a positive instruction about their range of application. I argue that while Proclus finds the syllogism a useful tool to reconstruct the different positions in the exegetical history of the argument, he does not accept it as an adequate reconstruction on his own account. The argument can be traced back most likely to the so-called ‘logical’ interpretations of the Parmenides that Proclus discusses – and dismisses – in the prologue to his commentary.