The genius of Einstein
For my purposes, the most important point of the article is how Einstein dealt with evidence that contradicted his beliefs. His response shows one key difference between science and pseudoscience. When Einstein formulated his Theory of Special Relativity, he believed in an unchanging universe that had always existed. However, gravity poses a tricky problem for such a view: Why doesn't gravity cause the collapse of all matter in the universe in on itself? Einstein postulated the existence of an antigravity/repulsive force that kept things in balance. When the Big Bang hypothesis was first postulated in the 1920's by Georges Lemaître and others, Einstein initially dismissed Lemaître's physics as "abominable." However, when Edwin Hubble showed that all the distant galaxies were racing away from one another at high velocity, as though from a large explosion, Einstein had no choice but to accept the evidence. He later even embraced it, saying, "This is the most beautiful and satisfactory explanation of creation to which I have ever listened." From then on, he characterized his repulsive force as greatest blunder of his scientific career.
That is perhaps the most important distinction between a true scientist and a pseudoscientist: The willingness to alter or renounce scientific theories, hypotheses, or beliefs when the evidence demands it. Pseudoscientists try to deny evidence and experiments that contradict their claims or twist them to make it seem as though they are compatible with their claims. But wait, you say. Scientists sometimes do this as well. True enough. Scientists are human too and therefore prone to the same tendency to hate to admit they are wrong that any other human being is prone to. The difference is that true scientists usually eventually swallow their pride and capitulate when the weight of evidence reveals their hypotheses and scientific beliefs to be untenable. Pseudoscientists virtually never do. Einstein was a true scientist.
Ironically, as the article points out, he may even have been correct about the repulsive force when he thought he was wrong...