"Every man ought to be inquisitive through every hour of his great adventure down to the day when he shall no longer cast a shadow in the sun. For if he dies without a question in his heart, what excuse is there for his continuance?"

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... placing economic activity in the context of the whole earth requires attention to the question of scale. Bigger is obviously not better, so the optimum scale of human economy in relation to the total economy becomes basically a question of sustainability. When the effects of the economy on the environment undercut the possibility of its own continuance, the scale is too large.

— John B. Cobb