Q: If metaphysical entities cannot be verified to exist, how can we say anything meaningful about them?

Martin: My position is that everything is metaphysical. (c.f. the question ‘Is everything metaphysical?’ on the Quora website: www.quora.com/search?q=everything+is+metaphysical).

So, everything that exists is metaphysical, including language and thought, sticks and stones, trees, all bodies, etc. In other words, there is nothing that is ‘material’ or ‘physical’ per se (which is a pure abstraction or a metaphysical theory).