One of the reasons why I challenge historical materialism in LFM is the way emerging marxism got stuck in the massive prejudice against idealism, for the wrong reasons. The result turned much of marxist thought into a sideshow to the mainline of philosophy, even as it brought it closer to the core of science. We can suspect that the downshifting into materialism in the nineteenth century condemned many fields to sterility. So it is worth asking: why this irrational prejudcie against idealism. There is no escape from the basic duality of materialims/idealism, so it was un-useful to try to force the left into a rote materialism.