free from bias

See: impartial
References in classic literature ?
Strange as it always is to consider any assembly in the act of submissively resigning itself to the dreariness of some complacent person, lord or commoner, whom three-fourths of it could, by no human means, raise out of the slough of inanity to their own intellectual level, it was particularly strange, and it was even particularly affecting, to see this crowd of earnest faces, whose honesty in the main no competent observer free from bias could doubt, so agitated by such a leader.