The goal of ethics, on the other hand, is to discover the most organised system of ends, of goods, which a rational life can realise. This goal of ethics can never be fully achieved, for so long as man acts and reflects he may pursue and conceive novel ends. But though the most elaborate system of ethics is in origin an expression of personal preferences, it is not therefore arbitrary and unjustifiable by reason. My values have their roots in my nature. I can exhibit them, demonstrate that they are mutually consistent and do not defeat the interests which underlie them. Furthermore I can declare that if any one honestly questioned his heart he might find that my values represented it. It is not to psychology, then, that one must turn for knowledge of human goods. For psychology, although it may analyse the efficient causes of desire, cannot estimate the value of its objects, of the ideal form of a rational life. If psychologists talk of a normal organism, they mean one whose desires are adjusted to its environment, the one most likely to survive. If they speak of superior organisms and civilisation, they mean increased ability for adjustment to a more complex environment. Thus though psychologists speak of normal and civilised they are unable either to define or to evaluate them. Knowledge of human goods is furnished by philosophers, when they are frank and speak for themselves; by the founders of religions, the saints, and the mystics; by the poets, and chiefly, as Socrates knew, by knowledge of oneself. Self-knowledge, though it may first look back upon the behaviour studied by psychology, moves in the opposite direction toward the objects sought. These it endeavours to comprehend, to purge of contradictions, to regard intently _sub specie mortalitatis_. From the vantage point of death one becomes a spectator of human life. Thought acquires the prestige of impersonality, without the sacrifice of its warm interest in life. The point of view of death differs from seeing things _sub specie æternitatis_ both in essence and in purpose. It does not abolish time or elevate mind to the contemplation of a necessary order, which is the function of seeing things _sub specie æternitatis_, although consideration of death (as in the Phædo) may do this. It enables one to regard life in its totality and, without projecting it against the background of nature, to estimate each partial aim in the perspective of all others, and thus to distinguish the objects one truly desires.