This thesis is concerned with whether or not thinking in fashion can be said to occur – and if so what kind of thinking? This thesis is largely based on fashion literature and trend theory as it is presented in On the nature of trends (Mackinney-Valentin, 2010), Trendsociology V 2.0 (Kongsholm & Frederiksen, 2015) and Mode – et fiolosofisk essay (Svendsen, 2005). By developing a new concept of fashion, fashion trends are established as being different from technological trends and other ‘nature’ or rational trends. There is fashion in any cultural arena from clothing and art, to science and philosophy; but there is no fashion in nature or in the animal kingdom, and neither is fashion immanent in any ideological system, where a? new product can solve a problem. Fashion trends are irrational to any kind of ideological logic, and therein lies the value of fashion; that fashion can be said to have a therapeutic effect on cultures or individuals with a problematic ideology, and that fashion actually results from truthful events. Fashion trends are immanent, transcendent changes, and that is what separates fashion items from design items, which can be termed immanent changes and which solve problems. Fashion trends come about through the lack of a reigning ideology, and fashion trends are therefore always in opposition to the situation in which they occur. A fashion trend can be small and only involve a limited subject matter and a small subculture, but fashion trends can also gain momentum and become the reigning ideology. According to this thesis, fashion is not the result of a social class struggle, as the sociological school of fashion and trend theory following Georg Simmel will have you believe. Fashion is instead, at its core, a kind of historical consciousness, caused by our incapability to perceive reality as it really is; which in a way is the effect of language. The new concept of fashion, which this thesis seeks to establish, emerges from the philosophical works of Martin Heidegger, Jacques Lacan, Dorthe Jørgensen, Georg Friedrich Von Hegel, Immanuel Kant, and Slavoj Zizek. Since our perception of reality is never without flaws, a new fashion is always about to arise out of the cracks in the current ideology. Thus, fashion is actually an epistemological phenomenon. Fashion seeks the truth that has been unspeakable in the situation. What is unspeakable in the situation is the unconscious, and by giving materiality to unconscious knowledge, fashion lets the truth of our unconscious desires speak. Fashion thinking is not just thinking about what fashion is and what styles will be ‘in’ next season. Both fashion and fashion thinking are much more radical than that. Fashion is always a radical continuity break with the thought of the situation, and fashion thinking is the type of thinking required for such work of fashion to come about. Thus, fashion thinking is thinking different that the situation, than the ideology, and than the thinking that language itself leads us to articulate. To achieve that kind of thinking, it is necessary to try to suspend the ways in which we usually perceive and think; through for example rational argumentation and the usual usage of word meanings. Essentially the goal of fashion thinking is to try to create new ways of understanding subject matters or even reality itself. At this point it should be clear, that the thinking required for fashion thinking, and the thinking which causes fashion to come about is not conscious thinking. The thinking in fashion is essentially unconscious thinking, and in order to be successful in fashion thinking it is also necessary to cultivate an ability to let the unconscious speak. Fashion can be understood as a hysteric discourse always questioning any reigning order, and fashion works can be understood to open up a therapeutic space analogous to that of the psycoanalytic treatment. When it comes to interpreting fashion trends, understanding them as manifestations (on par with dreams, slips of tongue, etc.) and using the analytic methodology developed by Lacanian psychoanalysis seems to be the most promising theoretic framework.