As anyone who has lived with a cat knows, they sometimes understand time much as we do, but other times their perception of time is baffling. After extensive observation, I believe I finally understand the perception of time by felis catus.
For the average domestic cat, a very few events are set: dawn, dusk, in some cases mealtime. Stanley is about 90% consistent now on waking me up 0-10 minutes before breakfast time, for example. But, for the vast majority of events, cats rely on a scale of time that is significantly different than most humans’.
Now: Much like the human concept, but with less tolerance for delays. “Now” does not mean “as soon as you put your shoes on”–it means instantly, and any delay is unacceptable, because it is no longer “now”.
Soon: This is a loose translation—the wordier but more-accurate term would be “as soon as I’m done with this”. This is a very flexible unit of time by human standards. It means whenever the cat is done with whatever it is currently doing, and thus ranges from [in human terms] a minute or less (when using the litterbox) through a few minutes (when eating dinner) to several hours (when sleeping). But from a cat’s point of view, these are all the same unit of time.
Forever: Any unit of time greater than “soon” and still today is approximately forever from a cat’s perspective. An hour until dinnertime? Forever. Waiting 3 minutes to go outside? Forever. You’re gone at work for 9 hours? Forever.
Forever and Ever: Longer than “forever,” up to and including some time tomorrow.
Any unit of time longer than a day, or any event further away in time than tomorrow, is literally incomprehensible to the vast majority of cats, so they have no term for it. For them, units of time beyond “forever and ever” are simply meaningless–the proverbial third dimension for a flatlander.