Thanks -- that helps. Maybe we can agree on some distinctions.
1.In some places in his writing, at least, Lovecraft perceives all that is as, intrinsically, brute phenomena, completely meaningless; we may begin to perceive this truth by contemplating the universe,* but really this truth applies also to the more familiar phenomena of nature here on earth, and to human history, and finally to ourselves. This conception contributes to his pronouncements such as "The most merciful thing in the world is the inability of the human mind to correlate its contents," that the progress of science is a fundamentally alienating activity because it reveals ever more ineluctably this nihilistic truth of things. However, a man of integrity may be able to face up to this bleak vision at least intermittently and to a degree.
2.I take him then to be saying, in such places, that human emotions towards all things (space and its contents, including ourselves) are incommensurate and irrelevant. It seems to me that an inescapable implication of this belief is that, while Lovecraft may prefer the company and writings of people who feel about things as he does, there really is no external criterion whereby his responses may be judged more appropriate than those of a man who pays no heed to anything beyond his petty concerns of getting a living and having a bit of fun. In fact all human activities, including all human mental activity, are "petty." He cannot allow exceptions.
3.But in other places he does seem to allow exceptions, does seem to say that to be stricken with awe is more appropriate to the nature of things such as the vastness and teeming abundance of the universe than not to be. I'm not quite sure how his former intuition can be squared with this latter one.
4.For context, it seems to me that we may discern several possible understandings of man-in-the-universe.
[a]The view I have attributed to Lovecraft in nos. 1 and 2 above. To this I added, earlier, what I understand to be Lovecraft's view that, knowing his thoughts to be incommensurate and irrelevant, a man may find comfort nevertheless in cultivating his inner world, his sensibility -- the associations he happens to have for loved scenes, the pleasure he takes in antique associations, the wonder he feels when looking through his telescope or at a sunset seen from a terrace, and so on. Lovecraft would say that a man might as well do this as part of the business of getting through his life, but of course when he dies it will be ultimately meaningless to say that this was part of a life lived well; like-minded friends may do so, but it's not really so. Life is futile because it is hopelessly anthropocentric to think that any way a person could live would be more appropriate to the facts of the universe than any other way.
The view you seem to suggest in remarks such as"To Lovecraft, however, these things have beauty and strangeness whether or not human beings are there to perceive it, as long as there is some sort of consciousness which can perceive the universe around it." Here it seems that there is a genuine complementarity between observing mind and observed universe, that they belong together, that some people "realize" this complementarity more fully in their lives than others do, and that these lives are lived better than lives that do not. Is this Lovecraft too? Can this understanding be reconciled with the futilitarian one I have just sketched?
[c]The view that I take Plato and Machen (and others) to have held, that beauty is a category of reality. It antedates the temporal and spatial universe. The universe that our senses perceive manifests in space and time an uncreated, transtemporal, transspatial beauty. Machen thus sometimes refers to things as "sacraments." The things we see, whether a lovely rose or damp, gritty bricks in the pavement of a London alley, participate in, have their being in, the eternal. (I don't think Machen was a pantheist ["all is god"] but he may have been a panentheist, i.e. one who holds that all that is, is "in" God.) I don't wish to argue that Machen was a philosopher. I doubt that he had worked out some of the issues that might arise with such a belief or intuition. But that this strong affirmation was part of his thought seems probable.
5.For Machen, beauty is antecedent to space and time, which manifest it; part of our being in the image and likeness of the creator inheres in our, too, being able to say, or to learn to say, that these things are beautiful and good. For Lovecraft, nothing could possibly antedate space and time (materiality), though after eons of space and time, creatures happen, by chance, to evolve who have nervous systems like ours, and some of these creatures imagine things such as "beauty" and project them on to the grinding mechanisms of space and time, which will keep in grinding away after those creatures are all extinct, their brief appearance and their inevitable disappearance, and the appearance and disappearance of their thoughts, being without any importance.
6.So now we can come back to the Chesterton passage. For Machen, "The flower is a vision because it is not only a vision. Or, if you will, it is a vision because it is not a dream." The flower perishes, but the beauty it manifested is changeless. "Let us so pass through the things temporal that we lose not the things eternal," said Machen, quoting from a prayer of the Church.** For the Lovecraft of my nos. 1 & 2 above in this message, the "visionary beauty" of the flower (or rather the sunset) is a "dream" -- that beauty is how-he-happens-to-feel or how-he-chooses-to-feel about what he perceives. It can't be anything else. He doesn't "owe" to the flower or the sunset any appreciation; but he may cultivate such appreciation because it is pleasant to do so while we pay out the hours we have before our extinction.
*Which to us appears "vast," but if we say it is "vast," we really are just saying something about how it affects some people's nervous systems and inevitably limited and "provincial" imaginations.
**This is actually from one of Machen's essays in which he rages against what he calls "puritanism" or "Protestantism" at times, though he was an Anglican, not a Roman Catholic. Machen is affronted when he finds the text of the prayer to read, "Let us so pass through the things temporal that we finally lose not the things eternal," taking this to be saying, basically: "Let us pass by the things temporal so that we can get through this earthly life -- pah! -- and attain heaven." He says, in effect -- Oh no, rather let us perceive the things of space and time as pervaded by, subsisting in, and manifesting the eternal, which otherwise we are likely to forget about as we grub a living and amuse ourselves with petty greeds and lusts; but let us, as we ought to do, take these things we see for what they are, "sacraments."
This by the way relates to Tolkien's argument in "On Fairy-Stories" about how such fantastical tales open our eyes, apt to become dimmed by trite familiarity, to the real beauty and goodness of common things.