Letter 92 (§21)

““But,” someone will say, “we know what is cold and what is hot; a lukewarm temperature lies between. Similarly, A is happy, and B is wretched, and C is neither happy nor wretched.” I wish to examine this figure, which is brought into play against us. If I add to your lukewarm water a larger quantity of cold water, the result will be cold water. But if I pour in a larger quantity of hot water, the water will finally become hot. In the case, however, of your man who is neither wretched nor happy, no matter how much I add to his troubles, he will not be unhappy, according to your argument; hence your figure offers no analogy.”