Better risk loss of truth than chance of error--that is your faith-vetoer's exact position. He is actively playing his stake as much as the believer is; he is backing the field against the religious hypothesis, just as the believer is backing the religious hypothesis against the field.
William James, John Dewey, John M. Capps, Donald Capps (2005). “James and Dewey on Belief and Experience”, p.107, University of Illinois Press