 In light of these difficulties it is best to start the genealogy of neutral monism with the big three: Ernst Mach, William James, and Bertrand Russell. Of the three, only Russell uses the label “neutral monism”. But there is widespread agreement that Mach, James, and Russell are the three most important philosophers in this tradition. A striking feature of traditional neutral monism—a reflection of the empiricist leanings of its protagonists—is the close tie between the neutral entities and experience. This connection has given rise to one of the most enduring criticisms of neutral monism (see section  7.2).  It is therefore important to note that this salient feature of traditional neutral monism need be no part of it (see section  5.1).