In one of my favourite papers about modal metaphysics, Rosen's 'The Limits of Contingency', Rosen develops the idea that there are two sets of modal notions which are apt to be conflated under the heading 'metaphysical modality'. Roughly: a correct conceivability modality, and a more properly metaphysical modality on which some things which are correctly conceivable are in any case not really possible.
In a recent paper, 'Correct Conceivability and its Role in the Epistemology of Modality' whichin a new book Les Principes Métaphysiques published by the College de France, Robert Michels considers an objection to Rosen's idea of a correct conceivability modality construed as giving an account of how considerrations about conceivability can takes us from non-modal to modal knowledge. I think this objection is based on a misunderstanding, as I will explain in this post.
Let me quote from Michels, first to set the scene, and then to see the objection and the main responses Michels considers.