In applying his method to introspection or the reports of people’s feelings, intentions, and beliefs, Wittgenstein constructed his well known and controversial “private language argument.” He reasoned that because words derive their meaning from public criteria that influence correct usage, there can’t be a wholly private language used to report only the private states of one person. He did not mean to claim that we do not have inner experiences, accessible only to those whose experience them, but rather that there are natural expressions of such experiences (pain, for example) that enable us to know the minds of others.