When I say that pelicans are birds, the truth of the statement follows inexorably from the meaning of the term "bird." If someone disagrees, or points at a living, breathing, flying pelican and says "That is not a bird," she simply does not know what the word "bird" means.' We criticize Lochner as formalistic because it treats the word "liberty" (or the words "life, liberty, or property, without due process of law") as being like the word "bird" and the privilege of contracting as being like a pelican, i.e., subsumed in the broader category. According to the reasoning in Lochner, if you don't know that contracting for labor without governmental control is an example of liberty, then you just don't know what the word "liberty" means.

Frederick Schauer, Frederick Schauer - Formali…, loc. 23