What evolutionary steps would be required to have a house cat evolve sapience?
Cat’s already have developed brains based on how folded the cerebral cortex is (estimated twice as much surface as dogs, with features comparable to about 90% of humans), but to make them on par with humans their brains would need to enlarge significantly.
Humans have had at least two evolutionary leaps in brain size. No one really knows why. One of the leaps coincides roughly with evidence of fire. Cooking with fire allowed humans to get more nutrition from the food they were already eating, but it’s debated whether fire led to bigger brains or bigger brains led to fire.
There was another evolutionary leap in human brains, and it’s assumed that people began living in larger communal groups around that time. Some theories suggest that as social groups became more complex, human brains expanded to track important people and extended family relationships. How would tracking social connections effect evolution? When you are more likely to die at the hands of others in your own species than from environment or predators, keeping track of who your friends are might be very important to survival, as well as having a good idea of what others are thinking (called Theory of Mind).
So you have a good chance with cats. They rank among “intelligent animals” but there is much debate about how intelligence should be compared (it’s important to take studies that compare human and cat intelligence with a little skepticism, and many online articles are playing to a willing audience). If you own a cat you’ve no doubt seen them display an understanding of mechanics they cannot operate (like doorknobs). It’s hard to imagine they will grow useable thumbs and start building complex machines.
But It does seem reasonable to imagine a similar evolutionary path of brain expansion that alters how cats co-exist in larger communities (female cats already live communally but male cats are typically solitary roamers), and they would probably need to start cooking their food. Even then you might need 200,000 to half-a-million years of evolution before a cat society starts resembling ours.