On what distinguishes great science fiction cinema from generic science fiction cinema.

Science fiction is a genre defined by premises rather than forms. The premise — what if technology did X, what if aliens existed, what if the future looked like Y — organizes the narrative but does not determine the film's quality.

Generic science fiction cinema uses its premise to generate plot and spectacle. The premise exists to create situations in which things happen, and the things that happen are thrilling or dangerous or involving. There is nothing wrong with this. Most genre films, most of the time, are doing exactly this.

Great science fiction cinema uses its premise as a philosophical lens: the what-if generates a question about the actual world that the film is genuinely trying to answer. Arrival uses first contact with aliens to ask about the relationship between language and time. Her uses artificial intelligence to ask about the relationship between desire and personhood. Blade Runner uses replicants to ask about the relationship between memory and identity.

The distinction is not about intelligence or prestige. The Terminator is not a philosophical film but it is a great science fiction film because it takes its premise seriously on its own terms. The failure mode is the science fiction film that has a serious premise and doesn't have the courage to ask the question the premise implies.