A common assumption in political economy is that there exists a consistent and well defined policy space. Often, this space is assumed to be adequately represented by a single `left' - `right' dimension. This paper makes the case that it is not only convenient but also meaningful to talk of the left and the right. Motivated, in part, by recent work in political psychology, this paper compares how individuals place themselves on a left-right scale with their answers to substantive policy questions, to provide evidence that the left-right scale has a consistent meaning across time and place. It is also finds consistent differences in how different demographic groups perceive the `left'-`right' continuum. In particular, it finds important differences associated with ageing, gender, income and education. It provides evidence that this is true for both abstract alternatives and concrete choices, questions of redistribution and broader conceptions of social justice. Heterogeneity is taken seriously, analysing variation within cohorts defined by country, date of birth, and gender - a variety of different forms are hypothesised, tested for, and rejected. Finally, it provides evidence that increases in income may lead to increased levels of political polarisation.