A shared world constituted by the prevailing appearances of things, and not conscious, either privately or collectively, of the falsity of the prevailing appearances of things is ultimately a false shared world. Kant proposes a conceptual realism that accepts appearances as veridical, in that they are all that we ever can have, but this is necessarily paired with an awareness that the thing itself eludes us. Take either proposition without the other, and it's simply a sanction for solipsism or authoritarianism.
One doesn't realize this until one spends some times with people and institutions and realize that they entirely consist of trying to be what they appear to be. It would be much better for both if they would try to be that which they didn't yet understand.