field as possible of suggested goods. It is probable that this utility of Metaphysics, in suggesting possible ideals, may sometimes be what is meant by the assertion that Ethics should be based on Metaphysics. It is not uncommon to find that which suggests a truth confused with that on which it logically depends; and I have already pointed out that Metaphysical have, in general, this superiority over Naturalistic systems; that they conceive the Supreme Good as something differing more widely from what exists here and now. But, if it be recognised that, in this sense, Ethics should, far more emphatically, be based on fiction, metaphysicians will, I think, admit that a connection of this kind between Metaphysics and Ethics would by no means justify the importance which they attribute to the bearing of the one study on the other.
72. We may, then, attribute the obstinate prejudice that a knowledge of supersensible reality is a necessary step to a knowledge of what is good in itself, partly to a failure to perceive that the subject of the latter judgment is not anything real as such, and partly to a failure to distinguish the cause of our perception of a truth from the reason why it is true. But these two causes will carry us only a very little way in our explanation of why Metaphysics should have been supposed to have a bearing upon Ethics. The first explanation which I have given would only account for the supposition that a thing’s reality is a necessary condition for tis goodness. This supposition is, indeed, commonly made; we find it commonly presupposed that unless a thing can be shewn to be involved in the constitution of reality, it cannot be good. And it is, therefore, worthwhile to insist that this is not the case; that Metaphysics is not even necessary to furnish part of the basis of Ethics. But when metaphysicians talk of basing Ethics on Metaphysics they commonly mean much more than this. They commonly mean that Metaphysics is the sole basis of Ethics—that it furnishes not only one necessary condition but all the conditions necessary to prove that certain things are good. And this view may, at first sight, appear to be held in two different forms. It may be asserted that merely to prove a thing supersensibly real is sufficient to prove it good: that the truly
