Steel_Wind said:
The problem is that SF, in order to work, operates under our laws of reality and physics.
Except that in a great deal of great SF, it doesn't. But what does that have to do with Harrison's admonition against making an exhaustive survey of you imaginary world?
You can bend them (a la Star Trek) but you must do so coherently and in a rational and ordered manner.
Trek makes hash out of science. Whole new species of particle physics were invented haphazardly whenever the writers felt the need the turn the crew into babies or sex maniacs (I exaggerate, barely).
For the record, I
do think Star Trek is rightly considered science fiction, because it addresses most of the major themes associated with the genre, in a serious fashion --usually. But claiming its approach to scientific speculation is ordered and rational is crazy talk.
That is the defining characteristic of speculative fiction.
The defining characteristics of SF are a whole other can of worms. At the very least its not merely a matter of scientific accuracy, or an honest attempt at it. Even hard SF stalwarts like Stephen Baxter sometimes write about things that are wholly outside what can meaningfully be called science; like car-sized FTL spaceships, star-killing handguns, and dark matter birds that flock malevolently in suns.
Because it is THAT rationality which distinguishes SF from Fantasy.
Or a pretense to that rationality.
Godzilla (or better, the original Gojira) isn't particularly rational, but it sure looks like science fiction, being a work that directly addresses the anxiety over rapid technological change, say, like the Bomb.
But in a SF world they do not have that license. The rules must work and be plausible and consistent - or the reader loses his suspension of disbelief and turns away from the SF tale in disgust.
SF writers have the license to engage in their own kinds of fantasy; force fields, instantaneous communication, FTL, magic gussied up as psionics, the utter inanity of most depictions of space warfare.
It is that very element which is the heart and soul of the distinction between SF and Fantasy
I think important differences between "SF" and "F" are thematic. That conceptualization at least results in a more stable definition of the genres.
And it is also why the quote mentioned in the OP's post is 100% dead frickkin wrong.
But the quote concerns worldbuilding when it occludes the main point of the work, not all attempts at creating a coherent counter-factual world.