It is actually a film that pretends to be about big ideas but that lacks even a single decent one.
What's the Big Idea Nolan presented to us? Space-time relativity? Wow. Welcome to the understanding of the nature of reality that Einstein established at the foot of the last century. This is the science that makes the GPS in your car possible. It isn't a theme which unfolds into meaning.
The special effects depicting space-time distortion are beautiful and the software that rendered them was engineered from equations worked up by a respected physicist. When the attempt is made to put the theory of relativity into the mouths of characters, however, the dialogue is bad. At one point, Nolan has one scientist explain that black holes aren't really holes but spheres to another scientist. They both might be expected to know this already, but the one explains it to the other anyway as if the one were some guy who slept through high school and the other was that dude at the party who watches a lot of Nova.
Outside of that subject, the movie tries out a handful of other ideas, none of which are all that good. Some contradict each other.
The hero is a reluctant, unhappy farmer whose career as a NASA pilot was forestalled by the nearing End of Days for life on planet earth. The nature of the apocalypse that befalls Earth in Interstellar is left vague and what is established makes no sense whatsoever. Nukes and war and avarice are mentioned here and there, but the main mechanism of Earth's demise is a blight which withers the planet's vegetation. Now only corn will grow and massive dust storms sweep the continents. It's un-fixable, we gotta build spaceships and evacuate Earth. That's what a secret cabal of what is apparently earth's only scientists concludes. The rest of the population is shambling around in the dust, growing corn and expecting the whole thing to hit bottom at some point.
Wouldn't it be more sensible to revive the dying planet you're on than to go to another galaxy looking for an already completely barren planet? Why did nobody think of that? Blight is perhaps a fine way to avoid making the dreaded, Republicans and/or Democrats Did The Apocalypse metaphor, which is fine, but Nolan hand-waves it like it just doesn't matter that this idea that interstellar exploration motivated by a global crisis that science and technology could more easily resolve by staying put makes no sense. Rather, it just seems that he wanted to evoke the Depression Era dust-bowl for stylistic purposes. This is not how you engage Big Ideas.
The education community in Interstellar is focused on the pragmatic concern of training kids in agriculture. The principal at the school our hero's son and daughter attend astutely puts it, "The world didn't run out of [gadgets], it ran out of food." He's right. A Professor adds that it's morally wrong to encourage kids to look to the stars when everyone's survival depends on this and several successive generations devoting themselves to tending to their soil and to one another. She's right. But our hero is angered by the idea that the world needs more farmers than explorers. "We used to look up and try to find our place in the stars," but now, "we look down to find our place in the dirt."
Somewhere in the middle of the film, the idea is proposed that love is or is like a physical force analogous to gravity, in that it can freely pass through time and space in ways which are mysterious to us, but the idea isn't developed enough to rate. It roughly mixes in with the Our Place in the Stars vs. the Our Place in the Dirt metaphor towards the thematic climax where all these half-chewed ideas clash into a paradox of meaning. The action at the climax seems to vindicate our hero's conceits about exploratory risk while simultaneously saying something like, "yea, but we only went out to the stars to discover ourselves". Why, we must wonder, did we undertake this journey in the first place if we could have discovered ourselves and saved the planet without the harrowing and extravagant trip to a distant galaxy?
I've spoiled about three fifths of Interstellar for you. Another fifth is good stuff and the remaining fifth is more of that half-chewed stuff that doesn't quite get over to the audience. How did the wormhole get there? How does our hero survive his trip through the event horizon of a black hole? What was that double-cross Michael Caine perpetrated all about? How do they justify knocking back beers on the front porch when wheat is supposedly extinct?
Whatever potentially decent ideas made it into Interstellar were poorly handled. The ideas of space-time relativity are big, powerful ideas, but Nolan failed to draw meaning from them. The plot objective is recursive. And yet the film didn't feel like a waste because it was so strongly crafted. Nolan's films are like this: intricate puzzle-boxes that unlock to reveal nothing but the creator's admiration for his own methods.
