ZONDI AJ (i) using a child or person who is mentally disabled for pornographic purposes as contemplated in sections 20(1) and 26(1) of the Criminal Law (Sexual Offences and Related Matters) Amendment Act, 2007, shall, unless some other period is expressly provided for by law, lapse after the expiration of a period of 20 years from the time when the offence was committed.‖ It is apparent that currently section 18 deals selectively with survivors of sexual violence. It precludes some survivors of sexual offences from access to criminal legal recourse, while protecting others. [47] The question is whether section 18, by treating the survivors of sexual violence selectively, is irrational as contended for by the parties. This calls for the critical examination of the means chosen by Parliament to determine whether these means are rationally related to the objective it sought to achieve. This is so because, although Parliament has authority to make laws it is required to exercise that power within the law; it cannot act irrationally. This Court held in Law Society of South Africa: ―A convenient starting point in evaluating these submissions is to restate, albeit tersely, the rationality standard that may be culled from the decisions of this court. The constitutional requirement of rationality is an incident of the rule of law, which in turn is a founding value of our Constitution. The rule of law requires that all public power must be sourced in law. This means that [s]tate actors exercise public power within the formal bounds of the law. Thus, when making laws, the legislature is constrained to act rationally. It may not act capriciously or arbitrarily. It must only act to achieve a legitimate government purpose. Thus, there must be a rational nexus between the legislative scheme and the pursuit of a legitimate government purpose. The requirement is meant ‗to promote the need for governmental action to relate to a defensible vision of the public good‘ and ‗to enhance the coherence and integrity‘ of legislative measures.‖33 (Footnotes omitted.) 33 Law Society of South Africa v Minister for Transport [2010] ZACC 25; 2011 (1) SA 400 (CC); 2011 (2) BCLR 150 (CC) at para 32. 20