Monthly Archives: May 2013

A Modalized Moral Argument

The follow argument attempts to do a few things:

A) It tries to ground the intuition that only God could be the ontological ground of moral values. That is, if God exists, then the cause of facts in the world is identical to the cause of values, and so facts cannot be divorced from values, a la Hume.

B) It provides a straightforward account of value by which a thing can be said to have value if goodness is said of it in relation to something. A thing could be said to have subjective and extrinsic value to, say, me if it is a good in virtue of my being. I take intrinsic value, then, to be a modal property where a thing is good in virtue of itself in all possible worlds. This is because a defender of intrinsic moral values will say that something like a human being is necessarily good in virtue of itself in all possible worlds, even if humans don’t obtain in every possible world. Rather, should a human come into existence in said world, it would have intrinsic goodness.

Finally, C) the argument attempts to show that the mere logical possibility of intrinsic values is sufficient to prove God’s existence. This depends upon my use of the S5 axiom, and a corollary to the Barcan Formula. So while the atheist might object to the traditional non-modal version of the moral argument on the grounds that objective and intrinsic moral values don’t actually exist, this version of the argument forces the atheist into the position of saying that intrinsic moral values are plausibly logically incoherent, or metaphysically impossible. But I see no reason why it is incoherent or impossible to be necessarily good in virtue of itself, at least prima facie.

One might note that my defense of the need for God as the ontological foundation for values depends upon a few theological notions. The first is that God is the eminent cause of truth and goodness in the world. Thus, God is the supreme exemplar of truth and goodness. Furthermore, Hume’s so called fork is circumvented in classical theism through the doctrine of Divine Simplicity, wherein Goodness and Truth are merely transcendental modes that, while perspectively distinct to finite knowers like us, are identical to Being itself, and therefore, God.


Gxy – x is good in virtue of y; something has intrinsic value iff it is necessarily good in virtue of itself, or □Gxx

t – the eminent cause of truth in all things

g – the eminent cause of goodness in all things

θx – x is divine

1. (∀x) [(□Gxx) → □(t = g)] (premise)
2. (∀x) {□(t = g) ≡ [□(x = t) & □(x = g)]} (premise)
3. (∀x) {[□(x = t) & □(x = g)] → θx} (premise)
4. ◊(∃x)□Gxx (premise)
→5. ~(∃x)θx (assumption)
↑6. ~θu (5 EI)
↑7. [□(u = t) & □(u = g)] → θu (3 UI)
↑8. ~[□(u = t) & □(u = g)] (6,7 MT)
↑9. □(t = g) ≡ [□(u = t) & □(u = g)] (2, UI)
↑10. {□(t = g) → [□(u = t) & □(u = g)]} & {[□(u = t) & □(u = g)] → □(t = g)} (9 Equiv)
↑11. □(t = g) → [□(u = t) & □(u = g)] (10 Simp)
↑12. ~□(t = g) (8,11 MT)
↑13. □Guu → □(t = g) (1 UI)
↑14. ~□Guu (12,13 MT)
↑15. (∀x)~□Gxx (14 UG)
16. ~(∃x)θx → (∀x)~□Gxx (5-15 CP)
17. ~(∃x)θx → ~(∃x) □Gxx (16, QN)
18. ◊(∃x)□Gxx → (∃x)◊□Gxx (CBF)
19. (∃x)◊□Gxx (4,18 MP)
20. (∃x)◊□Gxx → (∃x)□Gxx (S5 axiom)
21. (∃x)□Gxx (19,20 MP)
22. ~~(∃x)□Gxx (21 DN)
23. ~~(∃x)θx (17,22 MT)
24. (∃x)θx (23 DN)

More needs to be argued by way of the premises, but I think this moral argument is more powerful than those traditionally offered in defense of theism.

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