Fair enough but what about the joy of knowing as best we can, above all so that we are not deluded by nonsense? There is a great danger that the above thinking allows us to believe that little is known and there is no solidly based expertise to advise us. This is simply untrue.
Through science and research of all kinds and our own experience (correcting for our biases) we can try to know as best we can. Yes, we should always accept, as Umair says, that we cannot know perfectly. We can always learn more. But we can know enough to make informed decisions to better our lives.