From Atomic Habits author James Clear a bit on 1920s mountaineer George Mallory and the joy of climbing:
"People ask me, 'What is the use of climbing Mount Everest?' and my answer must at once be, 'It is of no use.' There is not the slightest prospect of any gain whatsoever. Oh, we may learn a little about the behavior of the human body at high altitudes, and possibly medical men may turn our observation to some account for the purposes of aviation. But otherwise nothing will come of it. We shall not bring back a single bit of gold or silver, not a gem, nor any coal or iron…"
What does this have to do with story and story structure? Desirability. The Linear mindset—the type that climbs mountains simply because they are there—does so because of natural blindness towards Desire and Ability's blending.
If you cannot understand that there is something in man which responds to the challenge of this mountain and goes out to meet it, that the struggle is the struggle of life itself upward and forever upward, then you won't see why we go. What we get from this adventure is just sheer joy. And joy is, after all, the end of life. We do not live to eat and make money. We eat and make money to be able to live. That is what life means and what life is for."
Probably more accurate to say "something in (a) man which responds to the challenge," but the quote captures the blend well enough regardless. The Linear mind instinctively responds to longing and capacity as if they were the same. The ability to climb a mountain is more than enough to justify a desire for doing so. The thrill of the chase rarely reserves time for a questioning of motives; once we have it, we no longer want it.
I am speaking, of course, on behalf of all Linear minds and the natural tendency to blend space (Ability) with time (Desire) into a continuum.
The Dramatica theory of story takes this instinct and weaves it into the fabric of the narrative structure. The mind of a story flips between dynamic pairs like these in search of a solution; projection and resolution merge into debilitating preconceptions of conflict.
Mallory's quote inspires a narrative of man's longing to be able because it is the essence of narrative.