The present chapter prepares the ground for proving the main thesis of part I: Different forms of objective realism and anti-realist critique in philosophy of science are in a double stalemate. It is first necessary to understand what kind of debate this is before I can be in a position to develop my concept of objective realism in the subsequent Chap. 3 . Clarifying the terms realism and anti-realism and mapping the debates around both terms helps me to identify their distinctive features in philosophy of science. To develop them further, it is crucial to consider their differences with comparable discussions about realism and anti-realism. Here, the debates about realism and anti-realism in various areas of philosophy are initially analysed from a bird’s eye view. My starting point is to conceptualise the fundamental concept of realism and its opposite of anti-realism as generally as possible (2.1). I argue that realism in the full sense consists only in the combination of two positive theses: an ontological thesis about independent existence and an epistemological thesis about the knowability of a certain entity or entities. Individually, however, these positive theses are also put forward as ontological realism and epistemological realism or rejected as ontological anti-realism and epistemological anti-realism. These distinctions prove relevant in a whole series of debates. I demonstrate the robustness of my definitions by mapping several related realism/anti-realism debates. The structure of these debates is modelled by distinguishing between local, metalocal and global forms of discourse: Debates that concern a clearly delimited area e.g. unobservable scientific-theoretical entities are local (2.2). Those that thematise several local, interrelated areas I call metalocal. These debates are more complex than local debates. When the ontological and epistemological question is all-inclusive, however, one enters the global realism/anti-realism debate (2.3). In doing so, I argue that the questions concerning both metaphysical and scientific realism are often falsely characterised as global or local, respectively, when in fact they both are metalocal (2.4).