True. But only if they appear in reality.
But if they come in one’s dreams (which is why we believe they can emerge in “the real world” ), one has to be aware that the ghost’s (and other “imaginary” creation’s) forces and the actions they are able to take depend only on what one believes that they can do. Because one’s beliefs/viewpoints/understandings of those creations (as establishments of their mind) are much stronger than the creations, then one can control them according to those views (if one knows how and why to do that). However, as inventions of one’s mind, as parts of one’s psyche, one has to learn how to confront own thoughts/values at first place – this referring to those capable of it. First one has to face with the self (and get rid of it!), and then face with this creations. On the other hand, those who haven’t put an end to the needs of satisfying the ego need to keep these illusions alive. Why? Simply: it is the pleasure that derives from being able to fight with (at least) imaginary things, being able to start a battle with something that the world and its “normal” population defines as a chimaera, for that will direct one to reaching exactly that “normality/naturalness” . Though it can also lead to liberating from the ego (but that’s another topic).
Sometimes… sometimes
one can enjoy! existing at the same wave-length with those creations. Isn’t it better to co-exist with them, than with the hypocrisy and ignorance offered by those “real and normal” people that we meet every day and are eager to say good-bye to?
Let your monsters be your guides, let them show you the paths in your life. Let no one else go side by side with you, except those exact monsters and powers of invention. For they are the strong ones, the ones that deserve your endurance, and, at the same time, your full attention. Remember that children only have the ability to create the best beautiful imaginary shapes? And the divinity and innocence is found at children’s hearts and souls only. So why kill the child in you? (and no, I’m not a paedophile
)
Anyways, I have something to ask: can someone please define the word “monster” for me? Maybe it’s just me not understanding it, and trying to get back to the childish imaginations that only a little girl can have in the best (short, of course) years of her childhood. 
"There is not enough love and goodness in this world, for us to be permitted to give any of it away to imaginary things." -FN-