“I’m sure the universe is full of intelligent life. It’s just been too intelligent to come here.”

“There was a time when genre fantasy was a mere annexe of the science-fiction marketplace. Nowadays, fantasy has the marketplace clout and the classic motifs of science fiction are increasingly being relegated to the status of stock ideas which can be deployed without discrimination alongside the traditional motifs of fantasy. It has been necessary to invent a special category of sf (“hard science fiction”) to distinguish that fugitive enclave of the marketplace where some sense of intellectual responsibility supposedly still holds, while more or less anything goes outside its beleaguered walls.”

“Gregory Benford might take some issue with this notion‥with his metaphor of all science fiction which is not hard science fiction being like ‘playing tennis with the net down’, meaning that hard science fiction is that science fiction which eschews violation of the presently known laws of the continuum.”

“When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”

“L’auteur de Hard Science Fiction peut aborder n’importe quel sujet à travers le prisme de la science, y compris la spiritualité, la politique et la nature humaine… à la condition d’éviter d’être doctrinaire… ce qui au fond il combat… Il se garde en réserve le droit d’inventer pour instruire sur les possibles et les impossibles et celui d’imaginer pour intéresser et divertir ses lecteurs.”

““Hard” science fiction is based on reality, the real world, as science has discovered and explained it. But it goes a step farther, beyond the known and into realms that have not been discovered and explained — yet.

The rule of thumb for a writer of “hard” science fiction is that the writer is free to use anything his or her imagination can invent and depict — so long as no one can show that it contradicts the tenets of known science.

The scope of “hard” science fiction is truly breathtaking: the entire universe and all of the past, present and future are the canvas on which we work.

All other forms of fiction are set in the here and now, on the Earth, where the sky is blue and there is solid ground beneath your feet. Science fiction tales, however, can take us to other worlds, other times.

In my own work, for example, I have taken my readers on a Grand Tour that shows how the human race might expand through the solar system and beyond. I have written stories about the biomedical breakthroughs that have the promise of making us forever young — or killing billions. I’ve set my characters at the walls of embattled Troy and across the endless steppes of Genghis Khan’s invincible Mongol armies. I’ve even done a tale about the end of the entire universe.

If the purpose of good fiction is to test the human heart in crucibles of fire, science fiction allows us to make the fire hotter, the test more grueling — and more interesting.

I’ve been writing “hard” science fiction all my life. I often tell people that I write historical novels that haven’t happened yet. But they will, just give ‘em time. Several of my earlier novels have already become history. We have flown to the Moon and built space stations in orbit. We have invented virtual reality technology, digital books, stem cell therapies. Perhaps we have accomplished sex in zero gravity, although no one has yet admitted it.”

“Le premier reproche, c’est que la hard-SF serait limitée et manquerait d’imagination. Il s’agit là d’une erreur d’interprétation des fondements de la hard-SF. Cette dernière s’interdit de transgresser ce qui est connu, mais cela ne signifie aucunement que l’auteur doit se tenir uniquement à ce qui est connu. Un ouvrage de hard-SF peut parfaitement contenir des technologies nouvelles, dont les fondements théoriques ne nous sont pas encore connus. La seule limitation, c’est qu’il ne faut pas contredire ce que nous savons déjà. Ainsi, la relativité interdit de se déplacer plus vite que la lumière, mais certains auteurs de hard-SF ne se gênent pas pour imaginer des moyens alternatifs. Simplement, ces moyens sont décrits en respectant l’état actuel de la science.”

“The only way to discover the limits of the possible is to go beyond them into the impossible.”

“Il existe un large consensus pour affirmer que la science-fiction se caractérise par un ou plusieurs éléments qui paraissent impossibles dans notre monde quotidien “normal”. Darko Suvin, l’un des pionniers de la recherche en science-fiction, a appelé cet élément le Novum (pluriel Nova), terme qui s’est généralement imposé par la suite. Il existe en revanche une absence de consensus sur la manière dont ce Novum se distingue des éléments typiques des contes et de la Fantasy. Les défenseurs de la hard science fiction disent que ce novum doit être explicable scientifiquement et compréhensible rationnellement. Cette position est très contestée puisque dans la pratique la plupart des nova de science-fiction sont de nature purement spéculative ou bien restent inexplicables par la science...

C’est la raison pour laquelle les derniers essais de définition de la science-fiction ne prennent plus comme point de départ la scientificité de la science-fiction, mais sa démarche caractéristique qui consiste à mettre la science au premier plan. La science-fiction est ainsi moins une question de plausibilité que de positionnement dans le monde fictionnel. La science-fiction prétend à la scientificité dans une sorte de “comme si scientifique” en se servant d’une rhétorique scientifique ou pseudo-scientifique. En littérature, cela s’exprime fréquemment par l’utilisation d’un jargon typique et souvent parodique qui sert simplement à dissimuler le fait que le novum en question est actuellement impossible.”

“The heart of the “hard SF” designation is the relationship of the science content and attitude to the rest of the narrative, and (for some readers, at least) the “hardness” or rigor of the science itself. One requirement for hard SF is procedural or intentional: a story should try to be accurate, logical, credible and rigorous in its use of current scientific and technical knowledge about which technology, phenomena, scenarios and situations that are practically and/or theoretically possible, and later discoveries do not necessarily invalidate the label.”