Chapter 14 Social investment: A paradigm in search of a new economic model and political mobilization. Nathalie Morel, Bruno Palier and Joakim Palme. We set out this book by asking a number of questions about the concept of social investment: What is it? Which policies can be associated with it? How does it perform? Is it relevant for the current and future challenges of modern welfare states? Behind these questions, there is of course a larger enterprise of searching for a strategy that would be able to regenerate the welfare state, promote social inclusion, create more and better jobs, and help address the challenges posed by the economic crisis, globalisation, population ageing and climate change. There is an underlying notion that the social investment strategy carries such potential. However, the aim of the book is also to critically assess the social investment approach in terms of the content and coherence of the ideas and policies put forward, its actual implementation and achievements, as well as its shortcomings. The book can hence be seen as an attempt to contribute to the discussion on the relevance of the social investment perspective for the new challenges that Europe and other continents are facing and, moreover, to base this discussion on a realistic view of how the world is working. In this concluding chapter we organise the examination of what we have learnt from the contributions to the book around a number of sub themes. We start out by discussing how far the social investment approach has come in terms of an emerging paradigm by mapping out its contours both at the ideational level and in terms of the policies implemented, and ask questions around its achievements. This, in turn, raises a number of critical issues around the design and implementation of social investment policies that are elaborated on in the second section of this chapter. In the third section, we put forward some ideas for a new form of economic thinking to underpin the social investment approach, and examine the politics of the approach in order to identify what could be the driving forces behind it. Finally, we look at some of the challenges ahead and discuss possible constraints for future reforms. The social investment perspective as an ‘emerging paradigm’ The ideas From an ideational point of view, the clear message is that a new and coherent set of ideas is emerging, even if there is some degree of ambiguity around some of the ideas (see Morel et al. and Jenson). From the ideational standpoint, the social investment perspective was developed with the dual ambition to modernise the welfare state so as to better address the new social risks and needs structure of contemporary societies and ensure the financial and political sustainability of the welfare state, and to sustain a different economy – the knowledge-based economy. Central to the social investment perspective is the attempt to reconcile social and economic goals.