Having laid this down, however, Sokrates immediately proceeds to refute it. In point of fact, false conceptions are found to prevail, not only in the wrong identification of present sensations with past impressions or thoughts, but also in the wrong identification of one past impression or thought with another. Thus a man, who has clearly engraved on his memorial tablet the conceptions of five, seven, eleven, twelve,--may nevertheless, when asked what is the sum of seven and five, commit error and answer eleven: thus mistaking eleven for twelve. We are thus placed in this dilemma--Either false opinion is an impossibility:--Or else, it is possible that what a man knows, he may not know. Which of the two do you choose?[112] [Footnote 112: Plato, Theæt. p. 196 C. [Greek: nu=n de\ ê)/toi ou)k e)/sti pseudê\s do/xa, ê)\ a(/ tis oi)=den, oi(=o/n te mê\ ei)de/nai; kai\ tou/tôn po/tera ai(rei=?]] [Side-note: He draws distinction between possessing knowledge, and having it actually in hand. Simile of the pigeon-cage with caught pigeons turned into it and flying about.] To this question no answer is given. But Sokrates,--after remarking on the confused and unphilosophical manner in which the debate has been conducted, both he and Theætêtus having perpetually employed the words _know_, _knowledge_, and their equivalents, as if the meaning of the words were ascertained, whereas the very problem debated is, to ascertain their meaning[113]--takes up another path of enquiry. He distinguishes between possessing knowledge,--and having it actually in hand or on his person: which distinction he illustrates by comparing the mind to a pigeon-cage. A man hunts and catches pigeons, then turns them into the cage, within the limits of which they fly about: when he wants to catch any one of them for use, he has to go through a second hunt, sometimes very troublesome: in which he may perhaps either fail altogether, or catch the wrong one instead of the right. The first hunt Sokrates compares to the acquisition of knowledge: the second, to the getting it into his hand for use.[114] A man may _know_, in the first sense, and _not know_, in the second: he may have to hunt about for the cognition which (in the first sense) he actually possesses. In trying to catch one cognition, he may confound it with another: and this constitutes false opinion--the confusion of two _cognita_ one with another.[115] [Footnote 113: Plato, Theæt. p. 196 D.] [Footnote 114: Plato, Theæt. p. 197-198.] [Footnote 115: Plato, Theæt. p. 199 C. [Greek: ê( tô=n e)pistêmô=n metallagê/].] [Side-note: Sokrates refutes this. Suggestion of Theætêtus--That there may be non-cognitions in the mind as well as cognitions, and that false opinion may consist in confounding one with the other. Sokrates rejects this.]