A recent topic about sitting in Burmese position made me think about exactly why meditation in full-lotus or half-lotus postures is practiced in Buddhism. I’ve heard many popular explanations for these practices, ranging from simple physical stability, to all sorts of physical or esoteric explanations related to subtle channels, etc. But what do the EBT’s actually say about this?
The main place in the SA / SN where I have seen materials related to meditation cross-legged, is the Anapana Samyutta. In this section, it is included in instructions for the meditator to go off into the wilderness or to some other empty place (e.g. SN 54.1). Aside from the Anapana Samyutta, it also appears commonly in the Iddhipada Samyutta in the context of the meditator flying into the air cross-legged (e.g. SN 51.11).
Does anyone have clear sources in the EBT’s that give a direct explanation for this practice? And if not, what are the best early or contemporaneous materials from Indian religious traditions that do clearly indicate its purpose?