When an idea is tested scientifically, argued logically, and rigorously probed for any intellectual value, and still makes no sense, it's probably wrong. I won't say always, as that is a surefire comeuppance, but usually. New age mysticism has zero scientific or logical merit. It's fake. All of history's gods are unproven, and most are nonsensical in nature. The safe bet is that they're fake. The same goes for conspiracy theories, most of which are unsubstantiated and ridiculous. They're false. Alternative medicine is no more effective than placebo. Fake. The list goes on.

It's simple. Is it factual in nature? (Making an objective, non-opinionated claim) Then apply the scientific method! For example: The claim that the Christian God exists is a factual claim. There's no verification of this, and scientific discovery tends to suggest otherwise. Even one discrepancy between it and reality means it's wrong.

Is it philosophical in nature? (Seeking to find a framework for how one or all should behave in certain situations) Then apply to the standard of human empathy. For example: Social Darwinism states that people with genetic imperfections are holding back humanity, so we should stop helping them because it's stalling the progress toward higher existence. Does it fit in with an empathetic worldview? No! Not even close. In other words, don't be Hitler.

Is it an argument to make a point? Examine it syllogistically. If the premises contain logical fallacies, it's wrong! Does the argument make sense? No? Scrap it. For example: The universe is complex. A watch is complex. A watch has a designer. Therefore, the universe has a designer as well. Therefore, God exists. This argument contains the following fallacies: false correlation, non sequitur, special pleading, argument from ignorance/personal incredulity, and a few others. Can you find them all? Regardless, the argument is trash.

Believing in falsehoods is pretty easy to avoid using these methods. The great thing about logic and science is that if used properly, they'll only ever make life better. Never in the history of humanity has ignorance solved problems better than knowledge. The more you know that is true, the better off you'll be.