“Just because you don't know something doesn't mean it's not true.”
“Just because you don't believe it[] [...]doesn't mean that it's not true.”
“Just because you don't understand something doesn't mean that it's nonsense.”
“Just because you don't believe in something does not mean that it's not true.”
“Just because you don't know how to do something doesn't mean it can't be done.”
“Just because an idea is true doesn't mean it can be proved. And just because an idea can be proved doesn't mean it's true.”