I borrowed the phrase "Strength to Dream" from Colin Wilson's book of that title, but only for the basic felicity of the phrase, not because I'm discussing any of Wilson's themes here. (I'm fairly sure I read it many years ago and have placed it on my to-be-reread list.)
I began thinking about the association of "strength" with "dreaming" thanks to the works of two famous writers who discussed how readers accept what I call metaphenomenal fiction. The first writer is Samuel T. Coleridge, whose most famous phrase in common parlance may not be anything from his poems, but from his autobiography, wherein he coined the phrase "suspension of disbelief."
In this idea originated the plan of the LYRICAL BALLADS; in which it was agreed, that my endeavours should be directed to persons and characters supernatural, or at least romantic; yet so as to transfer from our inward nature a human interest and a semblance of truth sufficient to procure for these shadows of imagination that willing suspension of disbelief for the moment, which constitutes poetic faith. Mr. Wordsworth, on the other hand, was to propose to himself as his object, to give the charm of novelty to things of every day, and to excite a feeling analogous to the supernatural, by awakening the mind's attention to the lethargy of custom, and directing it to the loveliness and the wonders of the world before us; an inexhaustible treasure, but for which, in consequence of the film of familiarity and selfish solicitude, we have eyes, yet see not, ears that hear not, and hearts that neither feel nor understand.
I confess that I have never read the full text of the bio, but I doubt that Coleridge uses the phrase again since none of the online references mention more than the one quote. The book concerns Coleridge's far-ranging theory of poetry, and so is not primarily about the ways fantasy-loving readers justify their preferences. In fact, the full context of "suspension of disbelief" is that Coleridge and William Wordsworth, in collaborating to produce various poems for their 1798 collection LYRICAL BALLADS, took two differing approaches to poetry, with Wordsworth favoring "things of every day" while Coleridge concentrated upon "shadows of imagination" that necessitated "poetic faith." Early in the history of this blog I described this literary dichotomy as one between works of "thematic realism" (Wordsworth) and "thematic escapism" (Coleridge), though in recent years I've inclined more toward an opposition between "verisimilitude" and "artifice," as in the last year's THE WHOLENESS OF HALF-TRUTHS PART 2:
"Verisimilitude" includes everything in a narrative allied to the limits of the physical continuum, while "artifice" includes everything in a narrative allied to the limitless nature of the continuum of abstract concepts.
Coleridge did not develop the "suspension of disbelief" concept, but many later writers quoted it and gave their takes on the idea, among them the second writer I mentioned above: Stephen King. King's 1981 book DANSE MACABRE largely concerns his theories about the horror genre, just as Coleridge's biography concerned poetry. King mentions "suspension of disbelief" in Chapter 4, where he extrapolates a meaning of "strength" from Coleridge's "suspension" metaphor.
...I believe [Coleridge] knew that disbelief is not like a balloon, which may be suspended in air with a minimum of effort; it is like a lead weight, which has to be hoisted... and held up by main force...it takes a sophisticated and muscular intellectual act to believe, even for a little while, in Nyarlathotep, the Blind Faceless One, the Howler in the Night.
And then he validates many fantasy-fans by turning a pitying eye upon those persons who reject all metaphenomenal content as being unreal in terms of real experience:
They simply can't lift the weight of fantasy. The muscles of the imagination have grown too weak.
Though I like King's extrapolation of Coleridge, ultimately it's a little too simple. I agree that it can take a "muscular intellectual act" to engage with stories that represent, not "the things of every day," but "shadows of imagination" that rule our dreaming selves. It does take "strength to dream," though not all dreams are equal. It takes a muscular intellect to imagine Nyarlathotep, but not so much to imagine the Children of the Corn (just to take a shot at one of King's less fruitful dream-shadows). On the same page from which I've quoted, King cheats a little by bracketing Lovecraft the "Escapist" with "Realist" Arthur Hailey, writer of bestsellers like AIRPORT. A fairer comparison to Lovecraft would be a Realist of some depth, like Joseph Conrad, who famously sneered at ghost stories. In Part 2 of 2015's THE DOMAIN GAME, I contrasted Conrad with Tolkien:
What Joseph Conrad deems to be artistic freedom relates to the perceived rigor of the naturalistic, while J.R.R. Tolkien associates freedom with marvelous creations like green suns.
Coleridge's contrast between his chosen form of poetry and that of his colleague Wordsworth is also a much fairer one, and I find it interesting when he says that Wordsworth does not just sedulously reproduce the everyday things he sees, but that he gives them "the charm of novelty." It does take a "muscular intellectual act" to re-organize the things of common experience to make them into art, even art that may argue that it's silly to read fantasy-stories (say, Austen's NORTHANGER ABBEY). To pursue an opposition for the dream-metaphor I've introduced, the advocate of realism may often believe that he's "awakened" from the delusional dreams of religion or superstition. I of course relate these modes further to the categories of cognitive restraint and affective freedom, but at present these do not need further elaboration in this new context.
On a small side-note, the decade in which Wordsworth and Coleridge collaborated on the LYRICAL BALLADS-- said by some to have launched the English Romantic movement-- is also the decade in which the Gothic novel enjoyed its first major flowering with such authors as Radcliffe and Lewis, with a second but distinct outgrowth evolving in the next twenty-odd years with Mary Shelley, E.T.A. Hoffmann, and Edgar Allan Poe. Though there had been scattered important metaphenomenal works throughout the 18th century, the 19th century would be conceived in the midst of ongoing arguments about the virtues of naturalistic fiction as against stories of fantasy, many of which are still argued about today, and which inform the warp and woof of modern fiction.