Social Democracy. I

Parade of SPD activists in Berlin on election day, January 19 1919. Bundesarchiv, Bild 146-1972-033-15 / Gebrüder Haeckel / CC-BY-SA 3.0, via Wikipedia.

Labor historian Eric Blanc, member of the Bread and Roses caucus of the Democratic Socialists of America, was on the radio trying to explain the DSA to the wider public, which I thought he was doing very well, but there was a point where I wanted to quibble (naturally, no socialist can ever bear to agree with another socialist about everything), which was when he described his ideological position in the DSA as on the organization's "right" (while acknowledging that it wasn't at all "right" in the general scheme of things), and I just think that doesn't mean what it's intended to mean—implying some kind of sympathy with a majority "center" imagined as too judicious to take sides, perfectly balanced between left and right views, an Aristotelian mean, as opposed to what it actually is, the gap at the middle of a bimodal distribution composed of the people who aren't able to ferret out enough information to make up their minds with any stability (maybe better illustrated as much wider and with narrower humps).

Via Wikipedia.

A more useful dichotomy would be the famous one proposed by young Karl Marx in the 1845 Theses on Feuerbach: "The philosophers have hitherto only interpreted the world in various ways. The point, however, is to change it." 

Marx regarded "left" and "right" as categories of bourgeois government, not something he, as an anti-bourgeois revolutionary, would want to apply to himself, but he did see this other distinction, between theory and praxis if you like, eventually serving on both sides himself, theorizing it in the reading room of the British Museum elaborating the edifice of Scientific Socialism at the same time as he was practicing it in his political participation in the 1848 German revolution (when he first joined a movement calling itself "Communist") and later the International Workingmen's Association, envisaged as the source of workers' parties seeking parliamentary power in Britain and on the Continent, and forming temporary alliances with the liberal bourgeois parties of the European left in efforts to improve the lot of the wage slaves of the Industrial Revolution, or the American Radical Republicans in their fight to abolish Black chattel slavery (as European correspondent of Horace Greeley's New York Herald).

Marx was both philosopher and activist, and it would be difficult to say in which capacity he would count as more "left" in today's sense, particularly hard-ass as a theorist and particularly lively as a practitioner; but I want to stress that praxis is pragmatic, and as much as "pragmatism" may often seem like faint-hearted hesitancy, it's really a matter of political judgment of what constitutes doing, as the Methodists say, "all the good you can".