The interpreter theory says that decision-making, judgment, perception, and virtually everything else that takes place in the brain is unconscious, and that what we understand as conscious thought is a distinct process that after the fact generates explanations for our actions and our experiences. Similar claims sometimes presented are that consciousness is an illusion or that consciousness is out of the loop in decision-making.

At first this idea seems nonsensical, but there is good evidence from neurology and psychology that the mind does in fact frequently function this way in the presence of neurological and psychological stressors (Confabulation and rationalization). Michael Gazzaniga developed this theory during his study of people with surgically split brains. It is only a small step to suppose that after-the-fact explanation is the norm. We argue that this structure of mind is unsurprising given the way the brain works and how the human brain has evolved from the brains of simpler animals that lack language and conscious thought. See Representational Opacity, but in short, the simpler brains of other animals easily make decisions without requiring the generation of explanations. Evolution follows an “if it ain't broke, don't fix it” strategy, so we make decisions in the same unconscious way. The unique human need to generate explanations for our actions or to argue in favor of possible group actions has been addressed by the addition of a distinct new capability, the interpreter.

Our concept of Story is closely related to the interpreter theory, while Jonathan Haidt uses the metaphor of the elephant and the rider. The Argumentative Theory goes on to explain how this separation of explanation from decision-making frees our internal story-teller to engage in biased stories intended to give others the same intuitive understanding that we've already intuitively arrived at.

One objection to the interpreter theory is “Wouldn't this mean there is no free will?” While this theory is not consistent with conscious free will as traditionally understood in philosophy, Unconscious free will is still quite possible.