Design is the fundamental shaping of the human world, an essential aspect of culture. When one sees the limits of the old, destructive ways of doing things and tries to imagine inhabiting the world differently, one has entered the realm of design. It is a hopeful realm. Design, by its nature, is a positive activity, a way of seeking solutions that can go deep to the heart of the problem and unleash extraordinary creativity.

For many, however, trying to make human activity more sustainable is a reductive exercise rather than a positive or deeply creative one. As industry takes, makes and wastes, the environmentally concerned often seek to merely minimize its impact. Growth is seen as bad and sustainability becomes a way of limiting harm rather than inspiring creative transformation.

But why not celebrate the things we make? The destructive qualities of today's cradle-to grave industrial system-the one-way trip to the landfill-are fundamentally a deeply engrained design problem, not an inevitable outcome of economic activity. Indeed, good design can transform the making of things into a positive, regenerative force.

Good design is based on the laws of nature. It sees the regenerative, cradle-to-cradle cycles of the natural world-the flows of nutrients and energy in living systems-as the model for and the context of human designs. Within this cradle-to-cradle framework, design can generate wholly positive effects, allowing us to create industrial and architectural systems, and even regional economic plans, that purify air, water and soil; use current solar income and generate no toxic waste; use materials that replenish the earth or can be perpetually recycled; and whose benefits enhance all life.

This emerging design paradigm, what my colleague Michael Braungart and I call Cradle-to-Cradle Design, is creating a new conception of materials and material flows. Just as in the natural world, in which one organism's waste cycles through an ecosystem to provide nourishment for other living things, cradle-to-cradle materials circulate in closed-loop cycles, providing nutrients for nature or industry.

The cradle-to-cradle model recognizes two metabolisms within which materials flow as nutrients. Materials designed to flow optimally in the biological metabolism, known as biological nutrients, can be safely returned to the environment after use to nourish living systems. The technical metabolism, designed to mirror the earth's cradle-to-cradle cycles, is a closed-loop system in which valuable, high-tech synthetics and mineral resources-technical nutrients-circulate in a perpetual cycle of production, recovery and remanufacture.

The daily application of the principles of Cradle-to-Cradle Design is stimulating the transformation of industry worldwide. Designers are developing safe, beneficial materials, products, supply chains, and manufacturing processes. Architects are creating buildings designed to generate more energy than they consume. Leading corporations are adopting cradle-to-cradle protocols that eliminate the concept of waste. Cities as influential as Chicago, and nations as vast as China, are applying cradle-to-cradle principles to community development and economic planning, showing the world that industry and ecology can indeed flourish together. All this, by design.

And so, by design, we can create a new world, a world of sustaining prosperity in which materials are nutritious, growth is good, and human activity supports all life.