It's not right, it's not even wrong

In science there can be no worse insult than being accused that one's activities are not science. Physicist Wolfgang Pauli committed the classical insult when he reportedly said of a younger colleage's paper:

"This isn’t right. It’s not even wrong."

This reflected the Popperian view of science in which a theory which is not falsifiable (cannot be proven wrong) is not considered scientific. The idea of falsifiability is well defined in Stanford University's article on Karl Popper (hat tip to Wikipedia):

"A theory is scientific only if it is refutable by a conceivable event. Every genuine test of a scientific theory, then, is logically an attempt to refute or to falsify it, and one genuine counter-instance falsifies the whole theory."

Most alternative medicine approaches are considered unfalsifiable and are therefore unscientific, or if they claim scientific justification, pseudoescientific. Consider homeopathy where solutions are diluted to the point where the supposed critical ingredient is no longer detectable. The water in which it was diluted is then said to retain a "memory" for that ingredient. This "memory" cannot be detected, the concept cannot be proven wrong and according to Popper's view is not scientific. Homeopathy is not right, it's not even wrong.

An well-known example of a falsifiable statement was that there were only white swans. It could be falsified simply by finding a black swan, which duly happened. Compare this with claims that parapsychology experiments fail because of the skeptical attitude of experimenters through the measurement effect in quantum mechanics affect the outcomes. If this is accepted, falsification becomes impossible and believers in parapsychology will always be able shift the goalposts.

Much of what is commonly called pseudoscience or quackery, can be described as not even wrong. In other words - it's bullshit.