 That both medical practice and lay thought shape disease concepts is undeniable. Because of this, we need to introduce a second distinction. Both naturalism and constructivism can take either a revisionist or a conservative form. A conservative view says that our folk concept of illness should constrain a theoretical picture of health and disease worked out by scientists and clinicians. A revisionist thinks that our existing concepts should be amended in the light of what inquiry uncovers. One could be a conservative or revisionist naturalist, as well as a conservative or revisionist constructivist.