Aune and others on ifs and cans
If I propose an analysis of 'S can do X' in terms of 'S will do X if C', I would obviously reject the idea, on which Lehrer's argument hinges, that 'S will do X if C' is consistent with 'S cannot do X if not-C' and 'not-C'. For me, 'S will do X if C' is supposed to mean 'S can do X'; and since the special suppositions, 'S cannot do X if not-C' and 'not-C' immediately entail 'S cannot do X', I would never grant that 'S will do X if C' is consistent with them.