 As pointed out earlier, Hacking, following Crombie, has proposed investigating the notion of style as a “new analytical tool” for history and philosophy of science. His preference is to speak of styles of reasoning (see also Mancosu 2005) as opposed to Fleck’s thought styles or Crombie’s styles of thinking (his most recent preference is to speak of ‘Styles of scientific thinking &amp; doing’; for the most recent discussion of Hacking’s program at the time of writing see Kusch 2010 and the special issue of Studies in History and Philosophy of Science (issue 43, 2012), including Hacking 2012 and several other contributions). The reason is that Hacking wants to move away from the psychological level of reasoning and work with the more ‘objective’ level of arguments. He explicitly defines his project as a continuation of Kant’s project aimed at explaining how objectivity is possible. And indeed, Hacking’s position rejects realism and embraces a strongly constitutive role for style. According to Hacking, styles are defined by a set of necessary conditions (he does not attempt, wisely, to provide sufficient conditions):