Why "mysterious ways" don't matter.

[pocaracas]

... a knowing subject only ever has belief that he knows something. The level of certainty that the subject possesses about a given object does not affect whether or not that object truly exists. You can know something for absolute certain and still be dead wrong.

Following your line of reasoning that which you just stated is merely a belief and no true knowledge is possible. Nihilist.

That's why standard philosophy dictionaries define "knowledge" as justified true belief.