In fact, there are likely millions who think that they know. I think of Maliha (of the blog "Lightness of Being"1). In an e-mail last year, Maliha listed eight or ten "ways of knowing" that god exists—even of knowing god, including intuition, insight, and imagination. (If I can find the e-mail, I'll add the others.)
And my cousin Vera finds god's existence "obvious," although she hasn't told me by what privileged sixth sense she knows this, except that she hinted it might be female intuition. (She had told me that though my unbelief troubled her, she had noticed that many of the men in our family have had trouble "believing in god," whereas the women haven't.)
I suspect that there are literally millions of Muslims like Maliha and millions of Christians like my cousin who feel they know that god exists. (I suppose there are even a few such Jews as well.) I'm willing to accept that and classify them as "'knowing' theists," but with the quotation marks around "knowing" to express my skepticism.
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- Maliha shut her blog down three days ago, explaining that "I need to discipline and allow myself to mature in some ways. I also hope that this move will quiet down the chatter within."