The problem I see is that vision is frankly teleological — it asserts or at least implies the causal efficacy of purpose in the real world. A vision of a desirable future functions as a lure, a pull toward itself. For the lure to be effective, like magnetic north, it has to embody real and objective value — not just subjective preferences of individuals.
I strongly believe in the causal efficacy of purpose as well as objective value, and it is a source of dismay to me that many others do not. Before we can save the biosphere, we will have to save the idea of purpose itself, or at least free it from the bondage in which it has been held by neo-darwinists for so long. Even those scientists who are too honest to deny the reality of purpose are nevertheless rendered half-hearted and feeble by the inconsistency between their personal life and the basic assumption of their science. It is hard to get excited about visions of a desirable future if you even half believe that purpose is an illusion.
— Herman Daly, Letter to Donella H. Meadows, June 1999
Reprinted in the Balaton Bulletin, Summer 1999