Euthyphros dilemma...

[Neo-Scholastic]

Why do irreducible nonphysical sources have the capacity to serve as foundation of value if physical sources do not? What is it about these hypothetical sources that makes them capable of providing foundation for intrinsic value?

My question and the failure to address it reveals the blind spot of materialism. You place a greater explanatory burden on dualist theories than on monist ones. My point was that your questions can be turned back on naturalistic theories, as in “Why does the physical ground of being have the capacity to serve as a foundation for physical properties?”

You can know many things about the material world, like forces and constants, without actually knowing what gives matter the power to express them. Materialist theories take for granted their assumption that, at base, an irreducible primal matter, distinct from the various properties assigned to it, underlies all physicality.

So when I ask, what gives matter the power to manifest physical properties, you have no answer. A source (Plotinus called it the Soul of All) for pure intentionality serves as the informing principle for primal matter, that which has a propensity to exist. The reason you can assign meaning and value onto physical reality is because you partake of that source.

Are we just natural intrinsic value bestowers?

No. That which bestows has inherent value. That is to say, you are the source of the value you give to the world.

... color isn't a real property of objects, but a mental interpretation of sense data...neither is color an essential property of the mind, it's something the mind creates... [and] ...value is [not] a property of mental things, but rather...value is a construction of the mental which it treats as a property of other things...

@MFM, your analogy fits. Color is a psychological (mental) phenomenon. Wavelength is a physical phenomenon. They are closely related; however, I think it begs the question to say one creates the other.