Consequentialist libertarian David D. Friedman, who believes that the NAP should be understood as a relative rather than absolute principle, defends his view by using a Sorites argument. Friedman begins by stating what he considers obvious: a neighbor aiming his flashlight at someone's property is not aggression, or if it is, it is only aggression in a trivial technical sense. However, aiming at the same property with a gigawatt laser is certainly aggression by any reasonable definition. Yet both flashlight and laser shine photons onto the property, so there must be some cutoff point of how many photons one is permitted to shine upon a property before it is considered aggression. However, the cutoff point cannot be found by deduction alone because of the Sorites paradox, so the non-aggression principle is necessarily ambiguous. Friedman points out the difficulty of undertaking any activity that poses a certain amount of risk to third parties (e.g. flying) if the permission of thousands of people that might be affected by the activity is required.