So maybe what you called "the world" here just is whatever it is we seem to understand. In this case, no need to assume knowledge. Some hallucinations may give you the certainty that you understand how the world works.
What about tangible evidence that your understanding leads to consistent, positive outcomes and a more enjoyable, flourishing life?
Hallucinations.
Hallucinations look just like tangible evidence. And you just can't ignore them.
I'm not sure how "positive outcomes and a more enjoyable, flourishing life" is necessary for understanding the world. But anyway, hallucinations can make your life looks enjoyable and flourishing.
EB
Not sure what you're trying to say here. Is seeing a car drive down the road just a hallucination, and not evidence that someone figured out how to build a motor? Obtaining the outcomes that you desire is evidence that your understanding of how to reach those outcomes was correct. And so positive outcomes, and an enjoyable flourishing life for a person is evidence that they know how to get what they want out of life.
Granted, yes people only know what they know, but that's the whole point. Enlightened naturalism would assume the world is knowable and that increasing one's knowledge about it would lead to a better life.
What is that part of the Buddhist eight-fold path? Right understanding.
Or in Taoism: wu-wei