 There are general problems with all kinds of naturalistic explanations as defeaters. First of all, as Gellman (2001) points out, most such explanations (like the psychoanalytic and socio-political ones) are put forward as hypotheses, not as established facts. The proponent assumes that the experiences are not veridical, then casts around for an explanation. This is not true of the neurological explanations, but they face another kind of weakness noted by Ellwood (1999): every experience, whatever its source, is accompanied by a corresponding neurological state. To argue that the experience is illusory because there is a corresponding brain state is fallacious. The same reasoning would lead us to conclude that sensory experiences are illusory, since in each sensory experience, there is some corresponding neurological state that is just like the state that occurs in the corresponding hallucination. The proponent of the naturalistic explanation as a defeater owes us some reason to believe that his or her argument is not just another skeptical argument from the veil of perception.