Some philosophers reject Jackson's Knowledge argument by claiming that Mary does not really learn a fact (what redness looks like) when she sees something red for the first time; she merely acquires a new ability (to recognize redness). But I think the argument is easily tweaked to pre-empt such responses. Consider:
1. It is a factual question whether you and I experience the same color sensations when looking at an object.
2. This question cannot be settled by any physical information (or scientific inquiry).
3. So there are non-physical facts.
This strikes me as a pretty strong argument. The only response I can immediately think of is the 'old fact new guise' response, which claims that the phenomenal fact mentioned in #1 is actually identical to some physical fact, albeit in a new (hence unrecognized) guise. But which physical fact is it? I find this claim very mysterious.