Like many philosophical questions, the demarcation problem has no quick-and-easy answer, but it has been extensively discussed. The Stanford Encyclopedia of Philosophy contains several interesting overview articles, including Sven Ove Hansson’s entry on “Science vs. Pseudoscience”, Julian Reiss and Jan Sprenger’s contribution on “Scientific Objectivity”, and Helen Longino’s article on “The Social Dimensions of Scientific Knowledge”. While you’re there, you may want to explore some other topics in philosophy as well!

Want to learn more about how particular fields have been debunked as pseudoscience? Sabrina Stierwalt discusses why contemporary astrology is not a science on the Everyday Einstein podcast. Homeopathy is debunked here by Ian Musgrave. This TED-Ed Collection reviews the science behind anthropogenic climate change. Creationism (and its successor, Intelligent Design) has been the topic of many court cases in the US, especially regarding whether or not it should be taught in science classes. The National Center for Science Education has an overview of all such cases — and in one case from 1982, McLean vs. Arkansas Board of Education, the expert witnesses included scientists and philosophers of science who explicitly discussed the difference between "science" and "pseudo-science."

Sadly, science denialism and pseudoscience are not a recent problem. Naomi Oreskes and David Conway’s Merchants of Doubt details the history of science denialism in the twentieth century. On the video resources page, you can find links to some of Oreskes’ public lectures about why we should trust science.