premise: arguments in justification of the prisoner
hypothesis: the best context for <mask> here is Adjustment of type (in printing), or of the final spacing of printed text, by spacing it so as to make it exactly fill a line, or line up at one edge of the allotted portion of the printed page; adjustment of a cut so as to hold it in the right place; also, the leads, quads, etc., used for making such adjustment; but not The act of justifying or the state of being justified; a showing or proving to be just or conformable to law, justice, right, or duty; defense.