In the 17th century, the philosopher John Locke noticed that the intellectuals of his day tended to make big claims about the world without supplying convincing sensory evidence.
Instead, Locke argued for intellectual honesty. If our evidence is not strong enough to answer a question, we should be brave enough to admit ignorance. This idea became one of the hallmarks of the scientific method.
Locke analysed this problem in his groundbreaking Essay Concerning Human Understanding . It's goal was to “inquire into the […] certainty and extent of human knowledge.”