It results from the conclusions of Chapter I, that all ethical questions fall under one or other of three classes. The first class contains but one question—the question What is the nature of that peculiar predicate, the relation of which to other things constitutes the object of all other ethical investigations? or, in other words, What is meant by good? This first question I have already attempted to answer. The peculiar predicate, by reference to which the sphere of Ethics must be defined, is simple, unanalysable, indefinable. There remain two classes questions with regard to the relation of this predicate to other things. We may ask either (1) To what things and in what degree does this predicate directly attach? What things are good in themselves? or (2) By what means shall we be able to make what exist in the world as good as possible? What causal relations hold between what is best in itself and other causal relations hold between what is best in itself and other things? (§ 24 ¶ 1)

In this and the two following chapters, I propose to discuss certain theories, which offer us an answer to the question What is good in itself? I say advisedly—an answer: for these theories are all characterised by the fact that, if true, they would simplify the study of Ethics very much. They all hold that there is only one kind of fact, of which the existence has any value at all. But they all also possess another characteristic, which is my reason for grouping them together and treating them first: namely that the main reason why the single kind of fact they name has been held to define the sole good, is that it has been held to define what is meant by good itself. In other words they are all theories of the end or ideal, the adoption of which has been chiefly caused by the commission of what I have called the naturalistic fallacy: they all confuse the first and second of the three possible questions which Ethics can ask. It is, indeed, this fact which explains their contention that only a single kind of thing is good. That a thing should be good, it has been thought, means that it possesses this single property: and hence (it is thought) only what possesses this property is good. The inference seems very natural; and yet what is meant by it is self-contradictory. For those who make it fail to perceive that their conclusion what possesses this property is good is a significant proposition: that it does not mean either what possesses this property, possesses this property or the word good denotes that a thing possesses this property. And yet, if it does not mean one or other of these two things, the inference contradicts its own premise. (§ 24 ¶ 2)

I propose, therefore, to discuss certain theories of what is good in itself, which are based on the naturalistic fallacy, in the sense that the commission of this fallacy has been the main cause of their wide acceptance. The discussion will be designed both (1) further to illustrate the fact that the naturalistic fallacy is a fallacy, or, in other words, that we are all aware of a certain simple quality, which (and not anything else) is what we mainly mean by the term good; and (2) to shew that not one, but many different things, possess this property. For I cannot hope to recommend the doctrine that things which are good do not owe their goodness to their common possession of any other property, without a criticism of the main doctrines, opposed to this, whose power to recommend themselves is proved by their wide prevalence. (§ 24 ¶ 3)