We do not know the world, but our world. Our beliefs are not true representations of a world objectively independent of us, but tools for living- for what would be better, a “true” belief that led you to despair and terror or a false belief that allowed you to continue?
Mathematics is not real, but it is useful. √(-1) is i and -i, though it cannot exist; even √2 cannot be expressed precisely. Even -1 does not exist, but is useful to describe a debt. God is like mathematics, God does not exist but is useful to explain human experience.
In a quantum universe where the photon always takes the shortest path to the receptor, so enabling plants to live, how could we imagine we understood anything at all?
Our language is only human, and our ideas shaped by the words we use to express them. Yet those words are imprecise, unable to share an experience: a peach, I tell you, is sweet, juicy and rich; it overwhelms my senses and I luxuriate in it. You think of your last experience of a peach, rather than mine. And writers especially, but everyone, come up with better metaphors, to better express ourselves. Lawyers distinguish cases.
The equator is a concept which cannot be observed, only calculated, and the Greenwich meridian is not an arbitrary choice because Britain is better than France- everyone admits it!
Science produces theories which are useful pictures of the world, and may be superseded as Newtonian gravity was by Einstein. If they let us predict outcomes they are useful enough.
Like other animals, we may simply not notice things which do not serve our purposes or threaten our desires. We don’t know and we cannot know THE world, absolutely. We can know only OUR world, a world shaped by our ideas, seen from our perspective, and built by us with our needs in view.
Nor do we know ourselves.
I got this from the Rev. Don Cupitt, who uses it to attack belief in God- though God may reveal God to us, continually rather than by one final revelation. Or, if Jesus was the final revelation, we are yet to fully understand Him and we can get closer to His Truth. Whether believing in God as a useful metaphor or as objective reality, the loving parent, or as childish illusion, we can learn to be more moral.
Philosophers may debate epistemology, but I move between the ideas according to which seems most useful at the time. And more often than I might like, I am like a weanèd child, not knowing, having to accept.