Scholarly Reflections
Koukl, Gregory. (2019). "Chapter Thirteen: Taking the Roof Off." In Tactics: A Game Plan for Discussing Your Christian Convictions (updated and expanded). (pp. 178-191).. Grand Rapids: Zondervan.
In this chapter, Koukl describes some worldviews which, if pushed to their logical ends, become absurd. He describes these views like maps which are not right for the journey at hand (Koukl 2019, p. 178). In these conversations, koukl suggests adopting the other person's point of view and pushing it to its logical conclusion. If the logical conclusion seems odd, "point it out and invite the person to reconsider the worldview route" (Koukl 2019, p. 179). The Latin phrase for this practice is reductio ad absurdum. The analysis works because eventually reality becomes apparent. If the reality is not consistent with the worldview, that worldview is in error (Koukl 2019, p. 180).
A very common issue which is dealt with by taking the roof off is moral relativism. If good and bad are indifferent or if they are mediated individually, a relativist should have no objection to what someone else might do. Confronted with the reality, everyone will object to something that someone else could do (Koukl 2019, p. 181).
To work with a reductio, Koukl provides a three step process. "First, reduce the person's point of view to its basic argument, assertion, principle, or moral rule" (Koukl 2019, p. 181). Be sure to confirm your understanding is correct. "Second, mentally give the idea a test drive to see where it leads" (Koukl 2019, p. 182). "Third, if you find a problem, point it out" (Koukl 2019, p. 182). Koukl gives a substantial number of examples of worldview claims which prove untenable.