In this paper I will argue that phenomenal consciousness is not sufficient to ontologically ground morality.  I will make two arguments for this thesis. First, I will argue that the thesis in question is logically improbable; secondly, I will use the deductive closure principle to make a short argument against phenomenal consciousness as constitutive of objective morality, and thereafter conclude that theism, since highly probable, involves this thesis to be false.
Here is the first argument:
- Phenomenal consciousness involves the what-its-like of experience.
- Objective morality is experience-independent.
- There is no such thing as phenomenal consciousness independent of experience.
- Therefore, nothing which can ground morality can be based on experience. (2)
- Therefore, phenomenal consciousness cannot be constitutive of objective morality. (1)-(4).
Here is a second argument:
- Theism is highly probable. 
- If theism is highly probable, phenomenal consciousness does not constitute the objectivity of morality (God does).
- Deductive closure principle: if S knows P and P->Q, then S knows Q.
- Therefore, if theism is true, and theism entails phenomenal consciousness as insufficient to ground the objectivity of morality, it follows that phenomenal consciousness is insufficient to ground the objectivity of morality. (1)-(4).
These are just two reasons I regard this attempt to save the objectivity of morality on naturalism to be unpromising. (Consider as a side argument the following: phenomenal consciousness is more probable on theism than naturalism; theism entails God as constitutive of objective morality, not phenomenal consciousness; therefore, phenomenal consciousness points towards its own inability to be constitutive of objective morality and the truth of theism).
 Arguing for phenomenal consciousness as constitutive of objective morality is usually an attempt to save objective morality on naturalism i.e., those denying a reductive ontology. (This is rather strange, though, as most naturalists reject, ontologically, morality).
 This second argument is tailored for the person who accepts theism (whereas the first is universal); I do this to reach both audiences (secular and non-secular alike).