What is the purpose of one's purpose?

At the beginning of a treatise, a Sanskrit author states, among other things, who should read his/her work (in modern terms, its target reader) and what is its purpose. Next, s/he explains what is the purpose's purpose. For instance, a treatise on verbal suffixes may have as its purpose to teach the usage of these suffixes. The purpose's purpose would be that a correct use of suffixes is needed in order to speak correctly, and to speak correctly means to think correctly. Obviously, one could keep on asking about the purpose's purpose's purpose.

Or not. One could also think that knowledge, of whatever subject, no matter how small and unimportant, is a good in itself, which does not need a further purpose.

As far as I am concerned, I always look for a purpose's purpose. Things become significant for me only insofar as they are part of a larger frame. I am happy to focus on the paper of a manuscript I am working on, I find the evolution in a letter's shape fascinating, I spent months on rare terms, such as prasaṅga. But I would not be able to do it, unless I thought of it as a step towards a better picture of, e.g., the development of Indian thought. Apart from my personal tendencies, I believe that focusing on the significance of what we study is ethically right. Also because human resources are limited, and I do not think it does not make any difference whether they are employed in trying to understand a miliar stone of Indian philosophy, or on a minor line in a minor work.