[The cat] and I have an agreement: I leave her alone and don't make sudden moves when I wake up to find her perched on my chest, staring with an unbl… - James Nicoll

Niven made a name for himself as a author, which is to say, someone whose SF provides enough technical detail that the reader can be certain that various mechanisms and events couldn't work the way the author has them working.

Look, I tried the cat experiment. On the third trial, the cat was dead. On each of the subsequent 413 trials, it remained dead. Am I doing something wrong?

A common issue with SF settings is that causally disconnected civilizations nevertheless are close enough in technological development that conflict is possible, rather than it being a matter of laser cannons against a thin film of single celled organisms.