What philosophical evidence is there against believing in non-physical entities?

[Panatheist]

I presume a waking experience involving a highly complex visual experience unrelated to my immediate environment involved a physical correlate in my brain.  Likewise when this involves the (purely subjective) experience of being transported entirely to a different location.  I call this an altered state because it is very different from how I usually perceive my reality.

Without any way of actually measuring you presume too much.  

Of course I cannot prove how I am experiencing the world anymore than you could prove you saw green aliens from Mars after ingesting acid.

No one asked you to, as far as I know.  I snipped the rest because it was elaboration on this theme.  I only asked if you had any way of determining that your experience or memory of that experience was an altered state as theres is..not an altered state as in "it's different than the way I usually see the world".  That;s important...because you're drawing some sort of validity from those other "x"s without knowing whether or not yours actually -was- one of them...rather than any number of other common cognitive ticks present between all of our ears.

Reading my post again I see how you could have thought I was making a necessary connection between atheism and skepticism of the paranormal.  I don't think Blackmore was theistic in a traditional sense, but probably believed in some source or reality that could be called God, and she does describe herself as an atheist.  All I meant is that she became an all-around skeptic to any sort of god, higher realm, the paranormal, all of that.  Seems to me that she was pretty New Age.

Now I get you.  You know what's interesting to me...that she was a researcher for two decades but not a skeptic.  How does that even work, right?

She researched to verify her own interpretations of her experiences and became disillusioned over the years, so that was the original motivator.

I'm not sure what exactly an altered state would entail for you. To clarify I mean an altered state of perception. I can only assume that involves a physical correlate. Everything we are aware of does.