 To entrench this idea he draws analogies between mathematic and logical knowledge and ethical knowledge (RG 29, 30, 32; KT 42, 85; FE 320). He is fan of synthetic a priori truths in ethics (and elsewhere) (FE 35–36; also 320). Since it might be possible to arrive at ethical knowledge by means of (mere) experience if moral terms were reducible to natural terms, this provides Ross with an incentive to show no such reduction is possible. He wants in short to protect a moral methodology prizing appeal to what ‘we’ think, the thoughts of the ‘best and most enlightened’ (FE 172), consensus amongst experts (OJ 119–120; FE 191) and various kinds of thought experiments. Indeed, it has been suggested that through the use of these tools it is possible to demonstrate that though ‘right’ is not synonymous with a natural property it nonetheless refers to some natural property, e.g., what has the greatest balance of justice, beneficence, fidelity, and so on, over injustice, non-maleficence and infidelity, and so on (Shaver 2007, 289). (This may be controversial if such notions as ‘justice’ are incapable of complete naturalization. If complete naturalization is not an option, then Ross may be forced to endorse a less palatable metaphysics.)