The text begins by defining the subject matter of ethics, arguing that the primary ethical question asks what is good in general, which must precede any determination of good conduct. The author establishes that 'good' is a simple, indefinable, and unanalysable notion, akin to simple sensory qualities like yellow, and that any attempt to define it by substituting another natural property commits the naturalistic fallacy. The discussion then moves through a critique of naturalistic ethics, examining theories that appeal to nature or evolution, such as those of Herbert Spencer, and demonstrating that evolutionistic criteria cannot logically determine what is morally higher or better.
Following naturalism, the work provides an extensive critique of hedonism, focusing particularly on the utilitarianism of John Stuart Mill. It refutes Mill's attempts to prove that pleasure is the sole desirable end through naturalistic arguments and the confusion of means with ends. The analysis extends to Henry Sidgwick's intuitionistic hedonism, questioning the assumption that consciousness of pleasure is the sole good and arguing instead for the existence of complex valuable wholes whose value differs from the sum of their parts.
The investigation then addresses metaphysical ethics, showing that supersensible realities and deductions from the nature of the absolute or the real have no logical bearing on ethical truths. The author rejects the epistemological doctrine that being good is equivalent to being willed or felt in a particular way, asserting that volition and feeling do not constitute ethical standards. Throughout these critiques, the text continually emphasizes the necessity of distinguishing between the definition of the good, the criteria of right action, and the nature of causal relations.
The concluding sections prepare the groundwork for an examination of human conduct by reinforcing the distinction between intrinsic value and value as a means. The argument stresses that fundamental ethical principles must be synthetic and self-evident, resting upon intuition rather than logical deduction from metaphysical or psychological premises. By dismantling prevailing ethical systems, the work clears the path for a systematic investigation of what things are good in themselves and how human action relates to these intrinsic values.
