 It has been suggested that an alternative to the view that mind lies behind and serves as the cause of behavior is the view that behavior serves as the criterion of mind (see  §1.1).  The former conception of mind in relation to behavior is associated with the following ideas: (i) my mind is private to me; (ii) I am both infallible and incorrigible with respect to my own mental states; and (iii) I can know my own mental state without having to observe anything about my body. This picture of mind is bolstered by the thought that, whatever another person says or does, it is always possible that they are deceiving me about what is going on in their minds—an extreme version of which leads to the thought that I am entirely deceived and all others are mere automata or zombies. In short, this conception of mind leads to the traditional epistemological problem of other minds. Standard responses to this problem—arguments from analogy and best explanation—draw a parallel between knowledge of another’s mind and explanation in science. In this connection Wittgenstein writes: “Misleading parallel: psychology treats of processes in the psychical sphere, as does physics in the physical” (1953: §571). In The Blue Book (24–25) Wittgenstein contrasts the business of citing criteria with that of giving symptoms in answer to the question, “How do you know?” He associates the giving of symptoms with the making of hypotheses; he associates the citing of criteria with “the grammar (the use)” of a word or with linguistic convention (1958: 23).