This thesis is an exploration of the UK knowledge economy, and its implications for the present and future lives of STEM (science, technology, engineering, mathematics) doctoral students at a research-intensive UK university. The research methodology included a critical literature review, focus groups, a large scale survey, and depth interviews. The thesis reports that the UK knowledge economy is a known phenomenon to young scientists and, across the population of young scientists, five distinct moral positions towards the knowledge economy are discerned. These five moral positions form a spectrum, ranging from 'anti' to 'pro' knowledge economy. Young scientists' moral positions on the knowledge economy are revealed to be a key aspect of their scientific identity. That the scientific identities of young scientists are in part moral contradicts dominant images of the scientist who, in Steven Pinker's words, is often construed as an 'amoral nerd' (Pinker in Shapin, 2008: xv). Young scientists' conceptions of identity are however, notable for their narrowness. Young scientists continue to rely upon the paradigm of modernity when forming their moral position on the knowledge economy, and constructing their identity. Accordingly, they view scientific identity as solid and stable. A game theory informed analysis illuminates how young scientists strategically tailor their scientific life in order to construct and sustain a stable identity; the achievement of which, they believe, is the best preparation for a scientific career. The irony of this finding is that contemporary science is shaped by postmodern forces: the knowledge economy and liquid modernity. These forces generate diversity, contradiction and perpetual change. It is argued that young scientists must develop a liquid scientific identity, fit for these conditions. Three reforms of the STEM PhD are proposed to enable universities to support young scientists to 'avoid fixation and keep the options open' (Bauman, 1995: 20).