If I am very interested in philosophy to the point where I would one day like to write a philosophical treatise or take part in the global exchange of philosophical ideas, but have little or no interest in teaching, would seeking a Ph.D in philosophy be unneccesary? This is putting aside the need for the discipline of setting one's mind to undertaking a thesis as I would likely obtain graduate education in a different, yet supplementary field?
But isn't there an odd tension between saying that you would like to write and take part in the exchange of philosophical ideas and saying that you have no interest in teaching? Isn't teaching In a university (the kind of teaching for which a PhD is required) one sort of exchange of ideas? And isn't it a particularly valuable one for the teachers who are thereby forced to make their ideas as clear and accessible as they can and to respond to the challenges of their students who in turn can teach them so much? How many philosophers can do good work without the constant challenges thrown up in their teaching?