> An apple is not an apple. An apple is a subjective construct that summarises the distinguishing features of a certain kind of object as it appears to our sens

> An apple is not an apple. An apple is a subjective construct that summarises the distinguishing features of a certain kind of object as it appears to our sense. It was clearly not about the apple, but about distinct entities with similar features. Now for another being these might not be similar, but something else probably is, disregard of different dimensions, different senses or the likes. As the observed reality for an alien species or actually any other species on this earth is different of course. > You cannot create an absolute internally consistent mathematics, because foundational axioms depend on subjective experience, not on objective logic. > And you can't prove a subjective experience objectively. I think the misconception comes from the fact that you need basic assumptions to build an abstraction. One of the most basic assumptions is that something like a shared reality exists and we're not for example in a virtual world or a dream. You can happily deny this shared reality, however I would not necessarily encourage you to touch fire (literally and figuratively speaking).