It's a very good question but it's not new (well, is any question new?).
Knowledge is by definition biased. Scientific knowledge is still biased, and what we know will always be limited by our experiences, ability to understand connections, and see the larger picture. We have not seen much of the universe, and there is so much about it that we don't understand. Our understanding of the universe is extremely limited by our location and inability to move around in it.
Whether it is even *possible* to know everything is one question. I don't think so, because "everything" is too large. Does it involve memories, for example? Will future scientists be able to know what we thought? That information will be lost to them. Can we know everything about places we haven't visited? How do we even start to identify the things that we don't know?
