People think this mental speculation, poetry, philosophy, that is spiritual. No. So long the subject matter is material, the concoction of the mind, speculation of the mind, the so-called philosophy, is also material: Revision history
Diff selection: Mark the radio buttons of the revisions to compare and hit enter or the button at the bottom.
Legend: (cur) = difference with latest revision, (prev) = difference with preceding revision, m = minor edit.