Neither the costs nor the benefits of adaptation to climate change have been systematically studied so far. This paper discusses the extent to which the vast body of literature on climate change impacts can provide insights into the scope and likely cost of adaptation. The ways in which the impacts literature deals with adaptation can be grouped into four categories: no adaptation, arbitrary adaptation, observed adaptation (analogues), and modeled adaptation (optimization). All four cases are characterized by the simple assumptions made about the mechanisms of adaptation. No or only scant attention is paid to the process of adapting to a new climate. Adaptation analysis has to acknowledge that people will be neither dumb nor brilliant at adapting. They are likely to see the need for change, but may be constrained in their ability to adept or in their comprehension of the permanence and direction of change.