For what counts, in the historicity of knowledge, is not opinions, nor the resemblances that can be established between them from period to period (there is indeed a 'resemblance' between Lamarck and a certain kind of evolutionism, as there is between the latter and the ideas of Diderot, or Robinet, or Beno de Maillet); what is important, what makes it possible to articulate the history of thought within itself, is its internal conditions of possibility.