(January 28, 2022 at 2:18 pm)Angrboda Wrote:(January 27, 2022 at 11:20 am)polymath257 Wrote: And if we allow for multiple 'substances', is it clear that all 'mental substances' are the same? Why not many different physical substances and many different mental substances? maybe, the distinction into 'physical substances' and 'mental substances' is, itself, problematic.
The problem with multiple substances is that you quickly run into questions of how the particles manage to interact with each other if they aren't all the same substance.
I don't see a problem. Why would things have to be the same 'substance' in order to interact?