When it comes to a theory of value, many economists, including the classic Adam Smith, believed in a concept of "market value", which is sort of like the philosophical "inherent value" of an item, except expressed in dollars. From a philosophical perspective, later economists and also philosophers have decided that the concept of value cannot exist without a valuer. What I mean by that is "value" is not subjective, but rather an item has several values rather than one value. There is the value I place on it, the value you place on it, the value my neighbour places on it, etc. This does not change the thing itself. Rather, value expresses a relation ship between the valuer and the "valuee". This negates the idea that subjective value implies that reality is not concrete and objective. Rather, the flaw is twofold. One, due to people observing that an item has many values and thinking it should only have one value. Secondly, due to people thinking value is intrinsic in the item being valued, when in fact it is intrinsic in the relationship between the valuer and the item being valued; if either one of those ceases to be then that instance of value goes away, though any other values associated with either of those and anything else still maintains.

The philosopher Ayn Rand takes much of the above view and adds to it saying that life is an end in and of itself, which is reason enough to exist. The problem she would see with some of the things I see being described in the posts here is confusing perception with reality. Plato (and probably Aristotle, though I am less familiar with him) would also agree with this out as well, perhaps citing his famous analogy of the cave from "Republic" about how what we see with our eyes are just shadows of their true eidos reflected on the cave wall. But that does not make their reality subjective. Rather, we need to strive to exit from that cave so we can see the true nature of things rather than merely the nature our eyes let us see. (And now you know the origins of that cave you appear in upon resurection in Achaea...) For example, just because we all perceive things differently does not mean it is subjective. Perhaps it just means each of us has different tools of perception and different capabilities to interpret things. I think both of these philosophers would also attack a common related word game people play with words to disprove existance, noting that words can be very fuzzy and meaningless if you think about them too long. What is "old", if you cannot identify the exact age when one has live passed the period known as "young"? Thus "old" does not exist. Etc., etc. The same theory above holds also that language is merely an artificial construct to symbolize reality, but it is not reality in and of itself. Thus all the word game did was disprove that language is reality, which no one ever claimed it was.

Another philosopher, Nietzsche, rejected all of that, claiming that the only thing you can be certain of is yourselfe, and all the rest is subjective. But he basically said that even if the only thing we can be certain is ourselves, it doesn't mean we can't enjoy life's pleasures. IE-Meaning is not necessairy for enjoyment. Eat and be merry! If you are certain of yourself, you can be certain of your happiness and what makes you happy, so go grab that. His philosophy was an extension of Schopenhauer's pessimism where he explicitly attacked Nihilism as the incorrect conclusion of Schopenhauer-like pessimism and believed his jovial yet tumultuous views were the proper answer.

I hate to bring these philosophers up since they are heavily related to the Roark IC persona so may seem like a biased endorsement, but it is really purely coincidence that they are the only ones I know of that address these sorts of things. (I actually would not endorse Nietszche in many things, but regardless, he does address these issues so is pertinent.) Other philisophers I've read like Rousseau, Locke, etc. don't seem to apply too well here.