What point is the author trying to make?

Directions: Read the following passage and answer the question.
Self-Analysis, apart from its scientific uses, has seldom rewarded those who have practiced it. To probe into the inner world of motive and desire has proved of small benefit to any one, whether hermit, monk or nun; indeed it has been altogether mischievous in result, unless the mind that probed, was especially healthy. Bitter has been the dissatisfaction, both with the process, and with what came of it, for being miserably superficial it could lead to no real knowledge of self, but simply centered self on self, producing instead of self-knowledge, self-consciousness, and often the beginnings of mental disease.
For fruitful self analysis it is apparently necessary then to have a clear, definite aim outside self -- such as achieving the gain of some special piece of knowledge, and we find such definite aims in psychology, and certain systems of philosophy – Greek, English, and German, in Plato, Locke, Kant, and in the meditations of Descartes, and many others. Self-analysis is the basis of psychological knowledge, but the science has been chiefly used to explain the methods by which we obtain knowledge of the outer world in relation to ourselves.
When a philosopher centers self on self, in order to know self as a result of introspection, the results have been disastrous, and have contributed nothing to knowledge, properly so-called. If religious self-examination has its dangers, so also has philosophical self-analysis for its own sake. It is a fascinating study for those who care for thought for thought's sake – the so-called Hamlets of the world, who are for ever revolving round the axes of their own ideas and dreams, and who never progress towards any clear issue.