 The strongest epistemic claims on behalf of self-knowledge are infallibility and omniscience. One is infallible about one’s own mental states if and only if (hereafter, “iff”) one cannot have a false belief to the effect that one is in a certain mental state. One is omniscient about one’s own states iff being in a mental state suffices for knowing that one is in that state. (This omniscience thesis is sometimes expressed by saying that mental states are self-intimating or self-presenting.) Few if any contemporary philosophers maintain that we are infallible or omniscient about all of our mental states. Here is a simple example that challenges both infallibility and omniscience. Kate trusts her therapist’s insights into her own psychology, and so she believes him when he tells her that she distrusts her mother. But the therapist is mistaken—in fact, Kate trusts her mother. Hence, Kate’s self-ascription I distrust my mother shows that she is fallible about her own attitudes (mistakenly taking herself to distrust her mother) and that she is not omniscient (she fails to recognize that she trusts her mother).