Recall that the master argument for skepticism went like this. First, you don’t know you’re not in a simulation. (This amounts to saying no to the Knowledge Question.) Second, if you don’t know you’re not in a simulation, you don’t know anything substantial about the external world. Conclusion: You don’t know anything substantial about the external world. If you accept both premises, you have to accept the conclusion and accept global skepticism about the external world.
