This idea of history having a ‘side’, which is liberal, enlightened and so on, harks back to the enlightenment of the 18th century, to the emergence of what David Hume called ‘these enlightened ages’, in sharp contrast to the side of the ‘dark ages’ of medievalism. The idea is that such a surge as the Enlightenment, having begun, is inevitable, tending unstoppably in one direction. This side of history is on the move to better times, and so if we wish these times for ourselves and others, we had better get on the right side. And that direction becomes ‘obvious’ to those with enlightened minds.

Paul Helm, “Which Side of History Are You On?” (HT: D. G. Hart)