Besides the issue of "subjective experience" that has already been brought up, there's also the question of what "thing" and "exists" mean.

I believe some form of MUH is correct so when I say exist I mean the same thing as in mathematics (in the sense of quantifying over various things). So by a thing I mean anything for which it is (at least in principle) possible to write down a mathematically precise definition.

Presumably abstract ideas and virtual particles fall under this category though in neither case am I sure because I don't know what you mean by abstract idea/I don't know enough physics. I not sure whether it possible to give a definition for subjective experience so I don't know whether subjective experiences have subjective experiences.

Also, it's "an aforementioned". That's especially important when speaking.

Substituted an a for an an.