Rationality means that a proposed course of action is justified with reasons and that these reasons are logically linked with the postulated conclusion. Although rationality is no longer considered as so central for good deliberation, our data show that rational arguments had about the same importance as personal stories to transform a discussion from a low to a high level of deliberation. By contrast, personal stories often also had a negative effect on deliberation, while we found only a single case, where a rational argumentation transformed a discussion from a high to a low level of deliberation. An example of a rational argument came from an ex-paramilitary in Colombia, who proposed that in order to procure more jobs for ex-combatants, business companies should get tax incentives for hiring them. Behind this argument is a logic that could stem from a textbook on taxes. The case where rational argumentation decreased deliberation was a nine minute long speech by a high police officer in a Brazilian favela, which was presented in such a hauty and arrogant way that it brought the discussion to a standstill. Overall, rationality fared better than personal stories for deliberation.