=27.= The common argument that things are good, because they are ‘natural,’ may involve either (1) the false proposition that the ‘normal,’ as such, is good; 41 =28.= or (2) the false proposition that the ‘necessary,’ as such, is good. 44 =29.= But a _systematised_ appeal to Nature is now most prevalent in connection with the term ‘Evolution.’ An examination of Mr Herbert Spencer’s Ethics will illustrate this form of Naturalism. 45 =30.= Darwin’s scientific theory of ‘natural selection,’ which has mainly caused the modern vogue of the term ‘Evolution,’ must be carefully distinguished from certain ideas which are commonly associated with the latter term. 47 =31.= Mr Spencer’s connection of Evolution with Ethics seems to shew the influence of the naturalistic fallacy; 48 =32.= but Mr Spencer is vague as to the ethical relations of ‘pleasure’ and ‘evolution,’ and his Naturalism may be mainly Naturalistic Hedonism. 49 =33.= A discussion of the third chapter of the _Data of Ethics_ serves to illustrate these two points and to shew that Mr Spencer is in utter confusion with regard to the fundamental principles of Ethics. 51 =34.= Three possible views as to the relation of Evolution to Ethics are distinguished from the naturalistic view to which it is proposed to confine the name ‘Evolutionistic Ethics.’ On any of these three views the relation would be unimportant, and the ‘Evolutionistic’ view, which makes it important, involves a double fallacy. 54 =35.= Summary of chapter. 58 CHAPTER III. HEDONISM. =36.= The prevalence of Hedonism is mainly due to the naturalistic fallacy. 59 =37.= Hedonism may be defined as the doctrine that ‘Pleasure is the sole good’: this doctrine has always been held by Hedonists and used by them as a fundamental ethical principle, although it has commonly been confused with others. 61 =38.= The method pursued in this chapter will consist in exposing the reasons commonly offered for the truth of Hedonism and in bringing out the reasons, which suffice to shew it untrue, by a criticism of J. S. Mill & H. Sidgwick. 63 A. =39.= Mill declares that ‘Happiness is the only thing desirable as an end,’ and insists that ‘Questions of ultimate ends are not amenable to direct proof’; 64