Anyone who can't trust their own mind and senses truly is lost, for that is the only means we can know this world, even if we do gain information from sources outside ourselves. For even this information will still be discovered and filtered through our own minds.
I understand some people suffer from mental illness and it is perhaps these people that become overly dependent on outer sources of "authority" for their world view. As someone whose senses and mind have never let them down I can't say I comprehend their view but for those who are weak of mind and lacking in self-belief science and religion may provide a useful crutch.
(Original comment made on a YouTube video here.)