Is similarity a fact of things in the world, or is it an observation made by

Is similarity a fact of things in the world, or is it an observation made by

Is similarity a fact of things in the world, or is it an observation made by sentient beings? Take two cats, for example. Is it an objective fact of the world that the two cats are similar (shape, size, biology, etc.)? Or are there, ontologically speaking, just two phenomena (or two portions of the phenomenal world) that we, as conscious beings, perceive as similar and categorize as cats?

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