My interests lie in consideration of conceptions of authenticity and inauthenticity from the perspective of ethical theories which conceive of the good for man with reference to human nature and concomitant beliefs regarding the most appropriate realisation of human capacities. Here, I find particular interest in the philosophical styles embodied by the existentialist and Lebensphilosophie movements. Such approaches sit outside the traditional frames of reference provided by deontological and utilitarian approaches to ethical reasoning and yet do I shall argue, share (...) significant similarities with ancient aretaic styles of ethics. Here, I take Aristotle to represent those aspects of ethical thought which are quintessentially of this period of intellectual history. I find not merely points of comparison but a fruitful way in which to re-examine the thought of thinkers such as Nietzsche, Scheler, Heidegger and Sartre with reference to styles of ethical enquiry which place primacy upon an objective conception of happiness which centres upon the appropriate realisation of human capacity understood with reference to Aristotle's Function Argument. I argue that phenomenological analysis shares a conception of self-perspicuity in which the agent reflects upon the full contents of their conscious experience. By this means, certain self-delusions which impede entry into the ethical life, may be removed. Additionally, whilst Aristotle's 'non-law' conception of ethics shares with existentialist thought an understanding of the human situation and its normative concerns in isolation from dualistic and theistic metaphysical speculation, such philosophy is still able to provide clear and objective ethical standards - standards often lacking within existentialism. For instance, whilst Nietzsche's pronouncement of the 'death of God' signals the death also of Christian morality, we find that such philosophy is not without normative implications and in fact can be derived to a large degree from assent towards a radical and more severe ethical self-discipline. Indeed, central certainly to the thought of Nietzsche, Heidegger and Sartre is an understanding of the role of self-deception in the human condition. Here a useful distinction may be made between those types of self-deception which may be understood as structural that is to say which are representative of an essential characteristic of human being at the abstract level - and those types of self-deception which may be described as 'motivated' or 'psychological' which relate to more specific types of self-deceptive engagement. I believe it is useful to examine both Nietzsche, Heidegger and Sartre through the lens of such interpretation, I find for instance that it is of use to examine the early Sartre as having a purely structural interpretation of bad faith (described by Jeanson as 'natural' bad-faith) whilst moving towards a psychological account in his later work, an account which has more specific moral implications with the possibility of 'willed conversion' to authenticity (Santoni). Additionally with Nietzsche, we also find a similar distinction between a self-deception which is in some sense preconditional and a motivational account of self-deception in which the agent infused with ressentiment falsifies reality in favour of subjective needs which are ultimately destructive of life-enhancement. In this sense the vicious individual can be said to have achieved merely a false optimum, and moreover, false from an objective standpoint. (shrink)