Historically and presently, many political theorists have argued that social critique needs to be oriented by a conception of what an ideally just or free society would look like. In the tradition of critical theory, this is often met with skepticism: We cannot conceptualize what such a society would be like, it is argued, since we our imaginative capacities are limited, we lack the proper concepts, or because any such ideal will be ideologically distorted. In my paper, I review versions of this argument as they have been made by Adorno and Marx. Against the negative conclusion that is widely endorsed in critical theory, I argue that conceptualizations of an ideal society are not only indispensable for a critical theory, but that they are also a necessary component of the process in which people can become aware of social contradictions. I conclude there is no reason for critical theorists to reject the project of conceptualizing a free and just society.