=66.= In this chapter I propose to deal with a type of ethical theory which is exemplified in the ethical views of the Stoics, of Spinoza, of Kant, and especially of a number of modern writers, whose views in this respect are mainly due to the influence of Hegel. These ethical theories have this in common, that they use some _metaphysical_ proposition as a ground for inferring some fundamental proposition of Ethics. They all imply, and many of them expressly hold, that ethical truths follow logically from metaphysical truths--that Ethics should be based on _Metaphysics_. And the result is that they all describe the Supreme Good in _metaphysical_ terms. What, then, is to be understood by ‘metaphysical’? I use the term, as I explained in Chapter II., in opposition to ‘natural.’ I call those philosophers preeminently ‘metaphysical’ who have recognised most clearly that not everything which _is_ is a ‘natural object.’ ‘Metaphysicians’ have, therefore, the great merit of insisting that our knowledge is not confined to the things which we can touch and see and feel. They have always been much occupied, not only with that other class of natural objects which consists in mental facts, but also with the class of objects or properties of objects, which certainly do not exist in time, are not therefore parts of Nature, and which, in fact, do not exist at all. To this class, as I have said, belongs what we mean by the adjective ‘good.’ It is not _goodness_, but only the things or qualities which are good, which can exist in time--can have duration, and begin and cease to exist--can be objects of _perception_. But the most prominent members of this class are perhaps numbers. It is quite certain that two natural objects may exist; but it is equally certain that _two_ itself does not exist and never can. Two and two _are_ four. But that does not mean that either two or four exists. Yet it certainly means _something_. Two _is_ somehow, although it does not exist. And it is not only simple terms of propositions--the objects _about_ which we know truths--that belong to this class. The truths which we know about them form, perhaps, a still more important subdivision. No truth does, in fact, _exist_; but this is peculiarly obvious with regard to truths like ‘Two and two are four,’ in which the objects, _about_ which they are truths, do not exist either. It is with the recognition of such truths as these--truths which have been called ‘universal’--and of their essential unlikeness to what we can touch and see and feel, that metaphysics proper begins. Such ‘universal’ truths have always played a large part in the reasonings of metaphysicians from Plato’s time till now; and that they have directed attention to the difference between these truths and what I have called ‘natural objects’ is the chief contribution to knowledge which distinguishes them from that other class of philosophers--‘empirical’ philosophers--to which most Englishmen have belonged.