“Morality and the philosophy of morality,” argues the author, “differ in the same manner and in the same degree as geometry and the philosophy of geometry.  Of these two subjects, geometry consists of a series of positive and definite propositions, deduced one from another, in succession, by rigorous reasoning, and all resting upon certain definitions and self-evident axioms.  The philosophy of geometry is quite a different subject; it includes such inquiries as these:  Whence is the cogency of geometrical proof?  What is the evidence of the axioms and definitions?  What are the faculties by which we become aware of their truth? and the like.  The two kinds of speculation have been pursued, for the most part, by two different classes of persons,—­the geometers and the metaphysicians; for it has been far more the occupation of metaphysicians than of geometers to discuss such questions as I have stated, the nature of geometrical proofs, geometrical axioms, the geometrical faculty, and the like.  And if we construct a complete system of geometry, it will be almost exactly the same, whatever be the views which we take on these metaphysical questions.” [1]

Such a system Dr. Whewell wishes to construct in the field of ethics.  His aim is to give us a view of morality in which moral propositions are “deduced from axioms, by successive steps of reasoning, so far as to form a connected system of moral truth.”  Such a “sure and connected knowledge of the duties of man” would, he thinks, be of the greatest importance.

In accordance with this purpose, Dr. Whewell assumes that humanity, justice, truth, purity, order, earnestness, and moral purpose are fundamental principles of human action; and he thinks that all who admit as much as this will be able to go on with him in his development of a system of moral rules to govern the life of man.

It would hardly be worth while for me to speak at length of a way of treating ethics so little likely to be urged upon the attention of the reader who busies himself with the books which are appearing in our own day, were it not that we have here an admirable illustration of the attempt to teach ethics as though it were such a science as geometry.  The shortcomings of the method become very evident to one who reads the work attentively.

Thus, we are forced to ask ourselves, have we really a collection of ultimate moral principles which are analogous to the axioms of geometry?  For example, to take but a single instance, Dr. Whewell formulates the Principle of Truth as follows:  “We must conform to the universal understanding among men which the use of language implies";[2] and he remarks later; “The rules:  Lie not, Perform your promise, are of universal validity; and the conceptions of lie and of promise are so simple and distinct that, in general, the rules may be directly and easily applied.” [3]