Nagel's rationalism and tendency to present our human nature as a composite, structured around our capacity to reason, explains why he thinks that therapeutic or deflationary accounts of philosophy are simply complacent and that radical skepticism is, strictly speaking, irrefutable. The therapeutic or deflationary philosopher, influenced by the later philosophy of Ludwig Wittgenstein, reconciles people to the dependence of our worldview on our "form of life". Nagel accuses Wittgenstein and American philosopher of mind and language Donald Davidson of philosophical idealism. In both cases they ask people to take up an interpretative perspective to making sense of other speakers in the context of a shared, objective world. This, for Nagel, elevates contingent conditions of our make-up into criteria for that which is real. The result 'cuts the world down to size' and makes what there is dependent on what there can be interpreted to be. Nagel claims this is no better than more orthodox forms of idealism in which reality is claimed to be made up of mental items or claimed to be constitutively dependent on a form supplied by the mind.