Hilary Putnam has famously undergone some radical changes of mind with regard to the issue of scientific realism and its wider epistemological bearings. In this paper I defend the arguments put forward by early Putnam in his essays on the causal theory of reference as applied to natural-kind terms, despite his own later view that those arguments amounted to a form of 'metaphysical' realism which could not be sustained against various lines of sceptical attack. I discuss some of the reasons for Putnam's retreat, first to the theory of 'internal (or framework-relative) realism proposed in his middle-period writings, and then to a commonsensepragmatist stance which claims to resituate this whole discussion on ground that has not been trorldden into ruts by the contending philosophical schools. In particular I examine his protracted engagement with various forms of anti-realist doctrine (Michael Dummett's most prominent among them), with Wittgenstein's thinking about language-games or meaning-as-use, and with a range of sceptical- relativist positions adopted in the wake of Quine's influential attack on the two last 'dogmas' of logical empiricism. My paper seeks to show that Putnam has been over-impressed by some of the arguments — from these and other sources — which he takes to constitute a knock-down case against the kind of extemalist and causal-realist approach developed in his early essays. It concludes by re-stating that position in summary form and relating it to other, more recent defences of causal realism in epistemology and philosophy of science.