That's because only a real artist knows the actual anatomy of the terrible or the physiology of fear - the exact sort of lines and proportions that connect up with latent instincts or hereditary memories of fright, and the proper colour contrasts and lighting effects to stir the dormant sense of strangeness.
Contrary to what you may assume, I am not a pessimist but an indifferentist- that is, I don't make the mistake of thinking that the... cosmos... gives a damn one way or the the other about the especial wants and ultimate welfare of mosquitoes, rats, lice, dogs, men, horses, pterodactyls, trees, fungi, dodos, or other forms of biological energy.
A serious adult story must be true to something in life. Since marvel tales cannot be true to the events of life, they must shift their emphasis towards something to which they can be true; namely, certain wistful or restless moods of the human spirit, wherein it seeks to weave gossamer ladders of escape from the galling tyranny of time, space, and natural law.
I could not help feeling that they were evil things-- mountains of madness whose farther slopes looked out over some accursed ultimate abyss. That seething , half-luminous cloud-background held ineffable suggestions of a vague, ethereal beyondness far more than terrestrially spatial; and gave appalling reminders of the utter remoteness, separateness, desolation, and aeon-long death of this untrodden and unfathomed austral world.
The one test of the really weird (story) is simply this--whether or not there be excited in the reader a profound sense of dread, and of contact with unknown spheres and powers; a subtle attitude of awed listening, as if for the beating of black wings or the scratching of outside shapes and entities on the known universe's utmost rim.
A certain atmosphere of breathless and unexplainable dread of outer, unknown forces must be present; and there must be a hint, expressed with a seriousness and portentousness becoming its subject, of that most terrible conception of the human brain - a malign and particular suspension or defeat of those laws of Nature which are our only safeguard against the assaults of chaos and the daemons of unplumbed space .... Therefore we must judge a weird tale not by the author's intent, or by the mere mechanics of the plot; but by the emotional level which it attains at its least mundane point... The one test of the really weird is simply this - whether or not there be excited in the reader a profound sense of dread, and of contact with unknown spheres and powers; a subtle attitude of awed listening, as if for the beating of black wings or the scratching of outside shapes and entities on the known universe's utmost rim.
We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far.The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the deadly light into the peace and safety of a new dark age.
I'll tell you something of the forbidden horrors she led me into - something of the age-old horrors that even now are festering in out-of-the-way corners with a few monstrous priests to keep them alive. Some people know things about the universe that nobody ought to know, and can do things that nobody ought to be able to do.
He talked about terrible meetings in lonely places, of cyclopean ruins in the heart of the Maine woods beneath which vast staircases led down to abysses of nighted secrets, of complex angles that led through invisible walls to other regions of space and time, and of hideous exchanges of personality that permitted explorations in remote and forbidden places, on other worlds, and in different space-time continua.
As I shivered and brooded on the casting of that brain-blasting shadow, I knew that I had at last pried out one of earth's supreme horors-one of those nameless blights of outer voids whose faint demon scratchings we sometimes hear on the farthest rim of space, yet from which our own finite vision has given us a merciful immunity.
Would to Heaven we had never approached them at all, but had run back at top speed out of that blasphemous tunnel with the greasily smooth floors and the degenerate murals aping and mocking the things they had superseded-run back, before we had seen what we did see, and before our minds were burned with something which will never let us breathe easily again!