So much, I hope, will suffice to explain what I mean by the term ‘metaphysical,’ and to shew that it refers to a clear and important distinction. It was not necessary for my purpose to make the definition exhaustive or to shew that it corresponds in essentials with established usage. The distinction between ‘Nature’ and a supersensible reality is very familiar and very important: and since the metaphysician endeavours to _prove_ things with regard to a supersensible reality, and since he deals largely in truths which are _not_ mere natural facts, it is plain that his arguments, and errors (if any), will be of a more subtle kind than those which I have dealt with under the name of ‘Naturalism.’ For these two reasons it seemed convenient to treat ‘Metaphysical Ethics’ by themselves. =67.= I have said that those systems of Ethics, which I propose to call ‘Metaphysical,’ are characterised by the fact that they describe the Supreme Good in ‘metaphysical’ terms; and this has now been explained as meaning that they describe it in terms of something which (they hold) does exist, but does not exist in Nature--in terms of a supersensible reality. A ‘Metaphysical Ethics’ is marked by the fact that it makes the assertion: That which would be perfectly good is something which exists, but is not natural; that which has some characteristic possessed by a supersensible reality. Such an assertion was made by the Stoics when they asserted that a life in accordance with Nature was perfect. For they did not mean by ‘Nature,’ what I have so defined, but something supersensible which they inferred to exist, and which they held to be perfectly good. Such an assertion, again, is made by Spinoza when he tells us that we are more or less perfect, in proportion as we are more or less closely united with Absolute Substance by the ‘intellectual love’ of God. Such an assertion is made by Kant when he tells us that his ‘Kingdom of Ends’ is the ideal. And such, finally, is made by modern writers who tell us that the final and perfect end is to realise our _true_ selves--a self different both from the whole and from any part of that which exists here and now in Nature.