“Marx was right though.  There was something about all of that industrial machinery churning out volumes of goods unthinkable in a pre-industrial age.  But it wasn’t the machinery in and of itself that was the source of value any more than it was the workers.  Rather, it was the massive quantities of fossilised sunlight in the coal which powered the machinery which was one source of value.  And the calories in the food consumed by the workers was another – albeit weak – source of value.” Tim Watkins, Consciousness of Sheep, A Question of Value