Sentence:  Robinson sums up the conclusion of the first part of his book as being "that the task of the moralist is to set in their proper relation to one another the three different types of moral judgment . . . and so reveal the field of <WSD>morality</WSD> as a single self-coherent system". 
Meaning of the word marked with <WSD> tags:  Moral philosophy, the branch of philosophy which studies the grounds and nature of rightness, wrongness, good, and evil.