§3. If, however, this view of the scope of Ethics is accepted, the question arises why it is commonly taken to consist, to a great extent, of psychological discussion as to the `nature of the moral faculty'; especially as I have myself thought it right to include some discussion of this kind in the present treatise. For it does not at first appear why this should belong to Ethics, any more than discussions about the mathematical faculty or the faculty of sense-perception belong to mathematics and physics respectively. Why do we not simply start with certain premises, stating what ought to be done or sought, without considering the faculty by which we apprehend their truth?
One answer is that the moralist has a practical aim: we desire knowledge of right conduct in order to act on it. Now we cannot help believing what we see to be true, but we can help doing what we see to be right or wise, and in fact often do what we know to be wrong or unwise: thus we are forced to notice the existence in us of irrational springs of action, conflicting with our knowledge and preventing its practical realisation: and the very imperfectness of the connexion between our practical judgment and our will impels us to seek for more precise knowledge as to the nature of that connexion.
But this is not all. Men never ask, `Why should I believe what I see to be true?' but they frequently ask, `Why should I do what I see to be right?' It is easy to reply that the question is futile, since it could only be answered by a reference to some other recognised principle of right conduct, and the question might just as well be asked as regards that again, and so on. But still we do ask the question widely and continually, and therefore this demonstration of its futility is not completely satisfactory: we require besides some explanation of its persistency.
One explanation that may be offered is that, since we are moved to action not by moral judgment alone, but also by desires and inclinations that operate independently of moral judgment, the answer which we really want to the question `Why should I do it?' is one which does not merely prove a certain action to be right, but also stirs in us a predominant inclination to do the action.
That this explanation is true for some minds in some moods I would not deny. Still I think that when a man seriously asks `why he should do' anything, he commonly assumes in himself a determination to pursue whatever conduct may be shown by argument to be reasonable, even though it be very different from that to which his non-rational inclinations may prompt. And we are generally agreed that reasonable conduct in any case has to be determined on principles, in applying which the agent's inclination---as it exists apart from such determination---is only one element among several that have to be considered, and commonly not the most important element. But when we ask what these principles are, the diversity of answers which we find manifestly declared in the systems and fundamental formulae of professed moralists seems to be really present in the common practical reasoning of men generally; with this difference, that whereas the philosopher seeks unity of principle, and consistency of method at the risk of paradox, the unphilosophic man is apt to hold different principles at once, and to apply different methods in more or less confused combination. If this be so, we can offer another explanation of the persistent unsatisfied demand for an ultimate reason, above noticed. For if there are different views of the ultimate reasonableness of conduct, implicit in the thought of ordinary men, though not brought into clear relation to each other,-it is easy to see that any single answer to the question 'why' will not be completely satisfactory, as it will be given only from one of these points of view, and will always leave room to ask the question from some other.
I am myself convinced that this is the main explanation of the phenomenon: and it is on this conviction that the plan of the present treatise is based. We cannot, of course, regard as valid reasonings that lead to conflicting conclusions ; and I therefore assume as a fundamental postulate of Ethics, that so far as two methods conflict, one or other of them must be modified or rejected. But I think it fundamentally important to recognise, at the outset of Ethical inquiry, that there is a diversity of methods applied in ordinary practical thought.