Is Whatever Exists Knowable and Nameable?

Naiyāyikas are fond of a slogan, which often appears as a kind of motto in their texts:“Whatever exists is knowable and nameable” (astitvaṃ jñeyatvam abhidheyatvam). What does this mean? Is it true? The first part of this essay offers a brief explication of this important Nyāya thesis; the second part argues that, given certain plausible assumptions, the thesis is demonstrably false.