If you've ever gone to a psychic, read your horoscope, or felt better after wearing a particular crystal on your necklace, you probably know how "real" pseudoscience can seem. It's very convincing, so it can be difficult not to believe in it. But no pseudoscience is backed by evidence.
Believers in pseudoscience often claim they have evidence, but if you ask them to explain their evidence, it generally falls into two categories.
1. Anecdotal evidence. Anecdotal evidence comes from personal experience and storytelling. As you'll learn below, we can't always trust our personal experience, and as you already know, we certainly can't always trust stories others tell us. Because of this, scientists don't consider anecdotal evidence real evidence. Though it often leads scientists to look for real evidence, it isn't trustworthy enough to use within the field of science.
2. Incomplete or incorrect evidence. Some pseudoscience groups, like The Flat Earth Society, say they value evidence but only present incomplete or incorrect claims. On their website, theflatearthsociety.org, they list an FAQ page that includes a section about evidence, but every piece of “evidence” they provide is either entirely inaccurate or doesn't give the whole picture.
So why is scientific evidence any better? Well, as you learned above, scientists are very cautious about claiming something. Scientific claims go through a long and rigorous process before the scientific community accepts them as fact. For example, if you were to tell a scientist that a bracelet could improve their balance, they wouldn't be convinced if they simply felt more stable when wearing it. They would design an experiment to measure whether it improved balance, and even if the experiment succeeded and their balance was better after wearing the bracelet, they still wouldn't be convinced. After all, the balance they gained could have come from something else, like a change in mood or an energy drink. So, they would design a larger experiment with dozens of participants. If that experiment showed that the bracelet improved the balance of every participant, then other scientists would review it to make sure there weren't any errors or design problems. If the experiment was accepted and published, other scientists would assess it to see if it had any errors and then create their own experiments in an attempt to copy the effect. Only then would scientists begin to believe the claim.
It seems like a lot of work, but it is valuable and essential work. Through experience, scientists have realized that the only way to know something for sure is to be incredibly careful about what they count as evidence, and the "evidence" that pseudosciences provide isn't good enough. In fact, scientists have tested many pseudosciences, including balance bracelets, and found them to be inaccurate and ineffective.