 The third of the arguments that have been brought to bear against the argument from analogy requires careful consideration. The very premise that Hyslop believes recommends this way of supporting one’s belief in other minds is the one that some have thought to be irremediably problematic. Malcolm, inspired by the later work of Wittgenstein, has suggested that the premise—I know from my own case what it is like to think and feel—is committed to what he calls the “fundamental error” of thinking that one learns what thoughts and feelings are from one’s own case (Malcolm 1958: 974). This way of coming to learn about mind is associated with what is sometimes thought of as an ‘inward glance’ or introspection (cf. Locke 1689). It has been argued that this way of learning about mind or mental states is committed to the possibility of a private language (Wittgenstein 1953; Malcolm 1954). According to Malcolm, Wittgenstein advances both an “internal” and an “external” attack on the possibility of such a language (Malcolm 1954 [1966: 75]). The internal attack aims to show that, while a genuine language requires that one be able to articulate correctness conditions for the application of a word, it is not possible to articulate such conditions when the referent of the word is not intersubjectively available. As Wittgenstein points out: “Whatever is going to seem right to me is right. And that only means that here we can’t talk about ‘right’” (1953: §258). (For a statement of the “external” attack here see  §2.)  The private language argument aside, the suggestion that I can come to know about mental states from my own case leads to a conception of mind as something not observable in behavior but as something lying behind and causing behavior. Malcolm contrasts this way of thinking with what he labels a criterial view of the relationship between mind and behavior. Much ink has been spilled over trying to understand this proposed alternative way of thinking of mind in relation to behavior (see  §1.3).  However we understand this proposal, it is important to appreciate the difficulties thought to be associated with the idea that one learns from one’s own case what it is to think and feel: it is believed to lead inexorably to solipsism. (This was something arguably first appreciated by Thomas Reid; see  §4.1).  It should, however, be noted that solipsism comes in two varieties: epistemological and conceptual. While the argument from analogy is proposed as a way of avoiding the former, it is arguable that it is really the latter to which Malcolm and others are drawing our attention. In effect, the claim here is that use of the argument from analogy as a way of avoiding epistemological solipsism (the only mind I can know is my own) falls foul of conceptual solipsism (the only mind I can think about is my own). Discussion of the conceptual problem in connection with other minds may be thought to take us in a direction at odds with that taken when one approaches these matters from an epistemological perspective (for the conceptual problem see  §2.)