Three issues are central to the discussion of art and sustainability. The first regards form. If there is an "aesthetics of sustainability" (Kurt's term), then it should be based on something that art provides as a basis for aesthetic judgment. This need not be a physical object, or even an immaterial project. It might be a gesture or even a mental action. What forms, then, does art take in a culture of sustainability? Are they vastly different from the forms of art in mainstream visual culture, or are they sufficiently analogous to be easily understood in a new context?

Kurt's view of art in a modernist context leads her to characterize it as "a form of knowledge." This definition enables art to bring "aesthetic competence into the cognitive process-which makes it different from science and at the same time its equal."10 Its not clear what antecedents in modernism's past Kurt is referring to when she characterizes art as knowledge, but one might imagine conceptual art, the Situationists, and some Fluxus activities as examples. Kurt believes that characterizing art as a form of knowledge can empower it discursively.

Once art is recognized as a cognitive medium, integrating aesthetic creative knowledge into the sustainability discourse would have a retrospective effect on that discourse, would change it. Art as a mode means that sustainability is seen, felt, thought, and conceived differently-and communicated differently.11 Though Kurt's emphasis on art as a bearer of cognition brings it into relation with a discourse on sustainability, it does not clarify sufficiently what the boundaries of this discourse are, nor does it explain the contribution that art might make to it.

Adopting the broad definition of form that Kurt and others have provided leads to a second issue: art's relation to other practices that are concerned with sustainability. After recognizing art as a cognitive medium, how do we then distinguish its particular characteristics from those of architecture, landscape design, graphic design, community action, and additional activities that engage with problems of sustainability, especially when the projects appear to be similar?

A third issue is related to the second. How do we think about art that moves from discourse to action, art whose intent is to produce a useful result? And what about artists who generate ideas and plans rather than objects or actions? Are they planners or artists, and by what criteria do we evaluate their work? In the never-ending debates on the difference between art and design, the distinction usually comes down to the primacy of discourse in artistic practice and the fact that artists need not be accountable, as designers are, to produce something useful. But when artists want to achieve social results without identifying themselves as designers, how should the critical community respond, and why is the artists' work given special status in a museum or gallery if its aims are predominantly practical?