"Article IV. Section V. The Censor shall either commend or censor members of the Society at the conclusion of each general meeting."
The Censor is a member of the Executive Board, serving as the equivalent of the vice-president of the organization. Or, in Philo terms, the cranky old person. The Censor's primary role is to produce the Censor's Report at the conclusion of each meeting. The Censor also assumes the power of executive decision in cases where the Moderator has a conflict of interest.
There are no prerequisites for being Censor. Traditionally, the role has been given to the Moderator emeritus, but any member deemed worthy (and crotchety enough) of the position may be elected to it.
It should be noted that serving as Censor does not fulfill the executive board prerequisite for becoming Moderator.