In the Stanford Encyclopedia of Philosophy the article about Realism has an argument in section 2 presented by a philosopher named Field regarding Platonism.
The argument goes this way.
Platonic realism is committed to the existence of acausal objects and to the claim that these objects, and facts about them, are independent of anyone's beliefs, linguistic practices, conceptual schemes, and so on (in short to the claim that these objects, and facts about them, are language- and mind-independent).
Any causal explanation of reliability is incompatible with the acausality of mathematical objects.
Any non-causal explanation of reliability is incompatible with the language- and mind-independence of mathematical objects.
Any explanation of reliability must be causal or non-causal.
There is no explanation of reliability that is compatible with both the acausality and language- and mind-independence of mathematical objects. Therefore,
There is no explanation of reliability that is compatible with platonic realism.
But I don't understand the 3rd one. How is that any non-causal explanation of reliability is incompatible with the language- and mind-independence of mathematical objects.
Can somebody please explain this in simple terms ?