Physicist David Deutsch, though in favor of the many-worlds interpretation, states regarding quantum suicide that it would not work under the normal probability rules of quantum mechanics. Instead, one would need to add an additional assumption of ignoring worlds where the experimenter is not there. He believes that assumption is false. Physicist David Wallace argues that a decision theory analysis shows that a person who prefers certain life to certain death must prefer to keep themselves alive in worlds that are more likely outcomes, not just in less likely ones.