You cannot be an Aes Sedai unless you pass a test which makes you choose between, on one side, the evidence provided by all your senses, your memories and experience, and occam's razor, not to mention any sense of loyalty or responsibility you may have, and on the other side a voice in your head saying "The way back will come but once. Be steadfast."

Unless you are willing to forsake all evidence to obey that voice in your head, you will never survive the test for Acceptance.

And then they make an Ajah dedicated to reason out of the subset of women who passed this test.

The result of this? In The Gathering Storm Ferane, the 'First Reasoner' and a Sitter for the White Ajah, with two other Sisters of the White Ajah, get slapped around, 3-on-1, by a 19 year old girl armed with hollow platitudes and hypocritical self-serving preaching.