If a man, holding a belief which he was taught in childhood or persuaded of afterwards, keeps down and pushes away any doubts which arise about it in his mind, purposely avoids the reading of books and the company of men that call in question and discuss it, and regards as impious those questions which cannot easily be asked without disturbing it — the life of that man is one long sin against mankind.

William Kingdon Clifford (1845-1879) English mathematician and philosopher

“The Ethics of Belief,” Part 1 “The Duty of Inquiry,” Contemporary Review (Jan 1877)
    (Source)