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Limited Depth

Theories explain phenomena by appealing to some underlying cause or phenomena. Theories which do not appeal to an underlying cause, and instead simply appeal to membership in a category, commit the fallacy of limited depth.


  1. A society is free if and only if liberty is maximized and people are required to take responsibility for their actions. (Definitions of this sort are fairly common, especially on the internet. However, if a person is required to do something, then that person’s liberty is not maximized.)
  2. People are eligible to apply for a learner’s permit (to drive) if they have (a) no previous driving experience, (b) access to a vehicle, and (c) experience operating a motor vehicle. (A person cannot have experience operating a motor vehicle if they have no previous driving experience.)


Theories of this sort attempt to explain a phenomenon by showing that it is part of a category of similar phenomenon. Accept this, then press for an explanation of the wider category of phenomenon. Argue that a theory refers to a cause, not a classification.