I have read in a few books about writing science fiction that a compelling concept should override considerations for character, and possibly other things like setting or plot. I have the notion to write in a subgenre of science fiction known as philosophical science fiction (see here or here). Is what I stated really true in science fiction in general, and philosophical science fiction in particular?
Art is, in its truest form, the ability to communicate a concept through its medium; in novel writing, your medium is the story. The fundamental building blocks of a story are the plot, the characters, the setting, the themes, and so forth. As brilliant as your philosophy may be, if you fail to invest your reader in your idea, you've missed the trees in the forest.
Now, don't get me wrong. I'm not one of those advocates for "only show, never tell." Whenever someone tells me that, I tell them that people like Terry Pratchett or Neil Gaiman exist (or, in the case of the former, existed :( ) who spend their novels generally telling, but do so in an interesting way. You need a device to carry your idea - Pratchett's was humor and spoof, Gaiman's is his own unique blend of combing the everyday with the fantastical. If you strike that blend between device and concept, you've got a winner.
Of course, one should be careful not to push too far the other way. My favorite example of this is the Matrix. As much as I like the Matrix as an action movie, its philosophy felt (for want of a better word) very textbook and token. One common mistake when writing these "philosophical" texts is to state the question, but to never provide the answer, e.g. as if Hamlet dropped the curtains on "to be or not to be?" Dramatic, perhaps, but not enlightening.
TL;DR Concept and device have equal weighting. One cannot either have a topic but not engage the audience, or engage the audience but not have a topic.
If you lead with a compelling concept, you should write an essay. A story is not, principally, about exploring an idea. Principally it is about creating an experience. Creating an experience can be a fantastic way to explore the implications of an idea. But it can only do so effectively if it is first and foremost a compelling experience. We don't receive the philosophical implications of the experience if we don't first receive the experience itself in all of its force.
Think about Flowers for Algernon. The concept is simple: Mentally handicapped man receives treatment that makes him smart enough to figure out that the effect of his treatment is temporary. By itself, the concept is a punchline of a rather cruel joke. But that is not how we remember the book. We remember a profoundly moving experience of a man's personal tragedy. The whole story is built on a concept, and yet it is not the concept, but the personal story that moves us, that makes us remember Flowers for Algernon when so many other stories quickly fade from memory.
A concept, in other words, is never compelling in itself. A hundred other writers might have tackled the same concept and made something completely forgettable (and maybe they did). It is the characters and the writing and the vividness and poignancy of telling that make Flowers for Algernon compelling. So it must be with any story.
The concept is everything, but also not the only thing.
In The Left Hand of Darkness by Ursula Le Guin, she explores many concepts but the major one is gender and what gender means to both others and the id (ego/super-ego). What made it a Hugo winner wasn't the concept. It was the way she explored it, by building a world where the concept had evolved naturally and ran freely throughout.
In The Hand Maiden's Tale Margaret Atwood explores female subjugation and religious totalitarianism. It won the Nebula and Booker prizes because the field in which her ideas had been had been sewn... was a complex, extremely well imagined and cohesive world.
In Stranger in a Strange Land, Heinlein explores the concept of self, the nature of innocence and about a zillion other things. It won a Hugo and was named as one of 88 books that shaped America by Congress. The concepts in it were literally mind altering, but the reason it and many other Heinlein works were so popular, was his world building was like nothing that had ever been done.
The concepts were the keystone of each story and yet without the world that defined the rules of that concept, all would be shadows of their former selves.
A concept is extremely important, but it needs a lot of narrative support or it becomes an essay. All three books aren't exactly high concept sci-fi, but they take concept and give it a place to flourish. World building is critical if you don't want your concept to be only that. It doesn't have to be flashy, but it needs to be vivid, otherwise you're just preaching.
You ask if the concept should override the considerations of character etc. My question would be: why do you feel you need to choose one over the other? Why do you find yourself in a position where you feel that in order to explore a creative concept your characters must be, to take a few possible options, flat or inconsistent or boring?
And once you answer that question, I think you will open the door to a better story.
Do you have a character that does seemingly conflicting things? Then either split him into two characters, or consider what are the psychological underpinnings of this inconsistency (in your case, perhaps there are internal conflicts in the futuristic "concept" you are exploring).
Do you have a character that is simply the foil for the hero, making him overly simplistic? Ask yourself why someone would be that way, make them more than just a caricature. I think Ayn Rand tried to do this in, for example, "The Fountainhead" - and that was clearly a book that designed it's characters to serve the concept she was trying to promote.
And so on. You might even find that while trying to figure out how people function in this sci-fi setting in a deeper level, it will also bring you to deeper appreciation and exploration of the concept you want to focus on.
Strength in good writing comes from its unitary nature. Concept, characters, plot, settings, and the unfolding of the story itself should be all one thing. This may sound like waffle. It does have the drawback of being a high-level abstraction, but even high-level abstractions have their place.
In practical terms, stories can start from anywhere. If you are interested in writing philosophical science-fiction (hereafter, PSF), then you want to write with a concept. If so, you will need to look at a suitable setting where that concept naturally arises, the right characters who can personify aspects of the concept in a variety of ways, and especially the consequences of the concept on the characters and on the setting.
Above all you are writing a story. Always try to make sure the concept is in the service of the story. This is not an essay or a text book about the core concept.
For example, if your PSF story involved a near-future world where a device had been invented that could access parallel versions of Earth. Not radically different ones where, for example, Hitler won WW2, but parallel Earths with minor differences. Star Trek: The original Series had four seasons and not three, sort of thing.
This will raise questions about identity, causality and destiny (you can see different life choices made by different versions of the characters and how they work out), how this affect the nature of the economy, politics, even entertainment (remember that fourth season of ST:TOS, and what hit movies, books, TV shows not made in our world), and would some worlds be better than others or much worse? What would be the consequences of wanting to replace a version of yourself who had had a better life in his or her world.
Basically no matter how strong or powerful the core concept is, it is expression as a story that matters the most. The core concept of any PSF story is not a substitute for good storytelling. This means the characters must be well done, the setting must feel right, and the plot has to be the sort of plot that best illustrates what the consequences of the concept will be.
Let me give you an example of what is involved in working through a concept to be able to write good science-fiction. The British Sf author Bob Shaw devised the concept of slow glass. Glass that slowed down passing through it to an incredible amount. This was an extrapolation of what happens already in nature when light passes through any transparent medium.
What Shaw did was not simply write a story using the first possible consequence of slow glass. He carefully considered all the possible consequences of an invention like slow glass that he could think of. This process he said was like treating those consequences like the facets of a diamond. Turn it this way and certain possibilities emerged, then turn further and other possibilities appeared. It was only when he found the possibility arising from slow glass with the greatest emotional impact, then he used that to write a short story.
Shaw went on to write a series of slow glass short stories. Most of which were incorporated into a fix-up novel.
Consider doing the same thing. Think through as many consequences and as many possibilities related to a philosophical concept and find ways they lead to stories. When you find the one with most emotional impact, then that's the one should consider writing.
Good luck with writing philosophical science-fiction!
All bestselling fiction has a strong concept. The concept is the red thread that leads the reader through the story. It is the reference point against which the actions of the characters become meaningful.
I have been admonished by this site's community for saying so, but it is a banal truth that not all readers are highly intelligent. If you want to appeal to the less intellectual part of the reading public, you will have to provide (besides a simple language and uncomplicated characters) clear and unmistakable directions through your story. These directions, or this guide, is your concept.
Hollywood movies and million-selling books usually have a very simple, very clearly stated, and unmistakeable concept, and for all these the concept comes first.
As a writer, you can think of concept as the ground on which the character arc rests.
In literary fiction – another term many members of this community despise – all considerations for your readers may be set aside. In literary fiction you do not write to sell, but to realize an artistic vision. Therefore, that vision comes first. It may or may not entail a concept.
Where you place yourself between these two extremes is your decision.