When Lakatos uses the term "Demarcationists," he meant those philosophers of science who presuppose universal criteria for the separation of science from metaphysics. With these, he included those who, like Lakatos himself, restrict it to the separation of bad science from good science, or even those who use the criteria for grading scientific theories. Though the criteria may differ within the demarcationist schools, they believe universally that there is a demarcation, one that can be understood even by laymen as the basis of which products of knowledge can be compared. Thus, Leibniz thought a proposition could be appraised in isolation, Russell that only vast conjunctions of propositions could be appraised, and Lakatos that only research programmes could be so appraised.

Whether a theory is scientific or pseudo-scientific, they all concur, is a matter of Popper's "autonomous third world" concepts, that of a world discovered with the help of pure ideas. They believe that only what has been articulated can be appraised and that it can be done according to statue laws that anyone can understand.

To Demarcationists, the philosophers of science act as watchdogs of scientific standards by reconstructing the criteria scientists use to solve problems, and by determining whether or not the theories in question meet these criteria. while they do not expect all to adhere to the same criteria, they do, expect that each should recognize the faults that are inherent ln the ones to which they do adhere. On the other hand, they tend to favor policies that mirror their own. lnductivists forbid scientists from speculating, probablilists from uttering hypotheses without specifying their probability, and falsificationists from speculating ln the absence of potential falsificating evidence or from neglecting severe tests.

For Lakatos, the archetypal demarcationist is Karl Popper. It is Popper's school of philosophers of science that has been particularly instrumental in developing the modern demarcationist position. It was Popper who formulated the concept of demarcation. For that reason. the Demarcationist position is probably best illustrated by the derivation of Popper's theory of refutationism. This is rooted in his interpretation of Kant. Popper believed that the motivation for Kant's "Critique of Pure Reason" was the question of how we can have perfect knowledge, which Kant believed Newtonian physics to be, when we cannot derive it from reasoning. This is because pure reasoning always ends in antinomies, i.e. statements that can be proved both true and false. His answer was that time and space are simply the framework we use to locate concepts. Physical things and events are real, that is, empirical, but time and space are not.

According to Popper's interpretation," Kant stated that the limits to reasoning are the limits of sense experience. When we digest our sense data we actively impress the order and the laws of our intellect on them, our cosmos. bears the "imprint of our minds." The problem is that where Kant focused on the absolute truth of Newtonianism, Popper concentrated on doubts and questions. Where Kant derived his inspiration from Newtonian absolutism, Popper derived his from Einstein's refutation of Newton. It must have struck Popper that the perfect science, that is, Newtonianism, which had stood unchallenged for over two hundred years, had been refuted, then it must be that any theory that can be called "scientific" must too be refutable.

This led to the logical conclusion that the demarcation between science and metaphysics must be falsification. In particular Popper needed some clear and simple standards that would separate such acceptable science as Einstienian physics from theories he considered pseudo-scientific, like Marx's theory of history or Freuds psychoanalysis. His criteria was that, in order to qualify as science, a theory had to be stated in such a way that it was possible to refute it. Part of every Popperian theory had to be a set of potential falsifiers--empirical facts, which if found true, or crucial tests if failed, would decide the theory unequivocally false.

Although Lakatos was a dedicated follower of Popper, he Began to realize that such crucial tests could only be seen In hindsight. Kepler's ellipses, he pointed out, were admitted as crucial evidence for Newton and against Descartes only after a hundred years had passed. Also, since propositions can only be derived from other propositions. and not from facts, clashes between facts and propositions are not falsifications. but merely inconsistencies. The Popperian insistence that an experiment must be specified in advance such that if the results contradict the theory. The theory must be abandoned. results in most Important scientific theories being relegated to metaphysics.

What was Lakatos' answer? We cannot consider single theories or single tests. We must instead. consider scientific research programs, or series of theories. and test them for progress or degeneration. Crucial experiments do not refute theories, they only allow one to choose between rival research programmes. This scenario provides a clue to my second point, the motivation of the Demarcationist. Demarcationists and myself believe that there does exist a field of endeavor called science. Those who work in it use a set of methods theories. and attitudes that are different from others and this has resulted in great progress In both our understanding of the universe and our harnessing of its powers. There can be no question that a criterion of demarcation exists between the scientific and the pseudoscientific, a criterion that should be clear to anyone with or without scientific training, To ignore this is to ignore three centuries of scientific progress.