Definition 1: Ghosts are the "creatures" which might be made of particles as we are, but unseen (with the use of photons). Premise 1: We are made of particles or atoms which enable us to think and make us what we are (human creatures). Premise 2: Their might exist creatures which are made up of particles unseen (might even be dark matter) and might have the ability to do the activities as we can. Premise 3: Ghosts might exist. Does Science has any evidence to prove that such unseen-particle-built creature (Ghost) might not exist? I have no background on Dark matter, I just mentioned about it on the basis of my layman knowledge. Thank you.