> But take one thing and then another: you have two things. That’s true whether or not anyone notices.

You cannot justify this statement without equally justifying my position.

Say you conceive of a counterfactual world without any humans in it. You know that within this world there could be a rock and another rock, you understand that this would be two rocks, and so you are reassured that one and one is two, even though no one is watching within this counterfactual world.

All of this happened in your mind. All along, you were the observer of the supposedly unobserved world you conceived of.

You are the unavoidable human observer of any counterfactual world you conceive of. You intend the world to have no human observers, but your intention fails. It is impossible. The properties of a truly unobserved world are unknowable to you.

This is why the Enlightenment left Platonism behind centuries ago. We can't say what the world would be without us, because any attempt is not only constructed within the mind, but also contemplated and observed through the mind. You can't escape projecting your systems of ideas onto everything you think about.

Once this is taken into account, Platonism has no explanatory power and is nothing more than superfluous metaphysical mystification.