People tend to confuse lack of belief with belief in lack. If you don’t believe in X, that doesn’t mean you believe X doesn’t exist; it means you don’t have sufficient evidence to definitively conclude whether it exists or not, and you conclude that it is best to not believe in it until and unless further evidence is provided. In other words, you continue living your life like it doesn’t exist until and unless it’s shown that it does—because you can’t spend your life acting on everything that might or might not exist.