anti-realism rejection, in one or another form or area of inquiry, of realism, the view that there are knowable mind-independent facts, objects, or properties. Metaphysical realists make the general claim that there is a world of mind-independent objects. Realists in particular areas make more specific or limited claims. Thus moral realists hold that there are mind-independent moral properties, mathematical realists that there are mind-independent mathematical facts, scientific realists that scientific inquiry reveals the existence of previously unknown and unobservable mind-independent entities and properties. Antirealists deny either that facts of the relevant sort are mind-independent or that knowledge of such facts is possible. Berkeley’s subjective idealism, which claims that the world consists only of minds and their contents, is a metaphysical anti-realism. Constructivist anti-realists, on the other hand, deny that the world consists only of mental phenomena, but claim that it is constituted by, or constructed from, our evidence or beliefs. Many philosophers find constructivism implausible or even incoherent as a metaphysical doctrine, but much more plausible when restricted to a particular domain, such as ethics or mathematics. Debates between realists and anti-realists have been particularly intense in philosophy of science. Scientific realism has been rejected both by constructivists such as Kuhn, who hold that scientific facts are constructed by the scientific community, and by empiricists who hold that knowledge is limited to what can be observed. A sophisticated version of the latter doctrine is Bas van Fraassen’s constructive empiricism, which allows scientists free rein in constructing scientific models, but claims that evidence for such models confirms only their observable implications. See also CONSTRUCTIVISM , DIRECT REAL- ISM , MORAL REALISM , SCIENTIFIC REALIS. P.Gas.