Value is definable only in relational terms.  

Well, maybe not.  Everything we value has low entropy that we can make use of (though not everything that has low entropy has value for us).  

No animal can sustain itself by eating its own excrement--the excrement is a degraded, low-entropy output of the animal's life processes--though some animals (like bacteria and dung beetles) have evolved to eat the low-entropy outputs of others.  

I'm suggesting that a metaphysics of value has to account for two things:

Some values are relative.  You like pictures of Elvis painted on velvet, and I like poster-sized copies of impressionist paintings, and my friend won't stand to have any reproductions hanging in his house at all.  Each of these is "low entropy"--a bit of organized matter (not decayed pulp and faded ink or paint)--but we each value what we like, and wouldn't pay money for the other.  This is the subjective part of value, and why it's true to say that not all low entropy has value for us.  (Poisonous mushrooms are "low entropy," but they don't have value for us either.)  

But some values are objective.  Everyone prefers food that has not been eaten to food that has already passed through another person's digestive system.  A gallon of gasoline is more valuable than the exhaust, waste heat, and water vapor you produce when you burn it.  Coal is more valuable than ashes.  High grade ores are more valuable than low grade ores, and concentrated ingots of metal you can produce from them (with additional inputs of energy) are more valuable than either.  Low entropy is the physical basis of value.  

Subject, object, neatly united in one metaphysics.  

There are many great intellects out there: all they need is a new set of assumptions, and off they go.

Check out the assumptions of the emergent field of Ecological Economics.  This is the field in which you'll find Nicholas Georgescu-Roegen, whose "The Entropy Law and the Economic Process" stands as this field's equivalent to Smith's "Wealth of Nations."  It's a paradigm that accepts that economic activity is not exempt from the laws of thermodynamics; and that, in fact, in the absence of entropy, we'd have no need for a science of economics, since every good thing ever made would still exist, and we could push cars backwards to fill their gas tanks.  They don't and we can't; therefore, we experience scarcity; therefore, there's a niche for the science of thinking rationally and carefully about how to satisfy human wants with scarce means.  No entropy, no scarcity; no scarcity, no economists.  Entropy makes economists useful; it's a shame that more of them haven't returned the favor.  

My diary contains a few citations leading to more info about this field.  Minds are working in it.

Industrial society is not sustainable. Unsustainable systems change--or disappear.