Mario Bunge has repeatedly discussed contributions to philosophy and to science that are worthless at best and dangerous at worst, especially cases of pseudo-science. He clearly gives his reason in his latest essay on this matter: "The fact that science can be faked to the point of deceiving science lovers suggests the need for a rigorous sifting device". Moreover, this sifting has its rewards, as "sometimes intellectual gold comes mixed with muck". Furthermore, the sifting device is a demarcation of science, which answers interesting questions: what is valuable in science and what makes it tick? The question is under dispute. So before coming to it we should admit a few preliminary ideas that are more difficult to contest than ideas that purport to demarcate science.