Theravādins who have gone for refuge in the three jewels have a number of reliable sources for ascertaining valid knowledge:
- 1. the Pāli Tipiṭaka
2. the written & verbal testimony of noble persons
3. inferential perception
4. direct perception
Unfortunately, though, #1 and #2 constitute reliance on authority, which is not at all a solid basis for ascertaining valid knowledge. Authorities who are right on some questions can be mistaken about others. Even the Tipitaka contains passages here and there which are demonstrably wrong
Claims made from direct experience ("I saw it myself, and this is what I saw!") can also be unreliable, even when the witness is reporting their experience in good faith. They may have misinterpreted their experience or made some cognitive error. Similarly, inferences can be faulty.
A funny example of faulty reasoning is the ghost and the lampshade
story -- the credulous observer is convinced that his house is haunted because a lampshade appears to be moving as if tampered with by a ghost; however, he has failed to account for an electric fan below which is pumping currents of air in the direction of the lampshade.
But first, one has to abandon the limitations of accepting the false dhammas of atheistic and materialistic views.
One should not, however, surrender his or her critical thinking skills or encourage other people to do so. That would be harmful and unwise.