The paper argues that the concept of second nature has two aspects that are inherently bound up with one another. Firstly, second nature has to be conceived of as a concept that has a critical force. Secondly, art has to be understood as an essential part of what second nature is. The paper explains these two dimensions of the concept by drawing on Hegel’s and Heidegger’s conceptions of second nature as the nature of essentially incomplete beings. Since the incompleteness in question always has to be reproduced, human beings have to develop and constantly engage in practices of self-criticism. As a practice of self-criticism, art is constitutive of second nature understood in this way. Thus, the specificity of art is to be found in its form of self-criticism as articulated through objects, which for their part give orientation to beings that realize their second nature through their practices. In the end, art prompts them to revise and enliven these practices.