The thermodynamics of ghosts is something we need to review upon and I think we can get around the conservation of energy in this way. We know that there are atoms and subatomic particles all round us which occupy different quantum states which are obliged only to obey certain statistical laws (no strict causality here). That means that they are capable of holding information. Let us say then that a person's identity is constantly leaking off as information to the surrounding particles. This information IS THE PERSON, it's software, not hardware. The body is the hardware that houses a given person (software) but because the identity is constantly leaked to the cloud (as in computer science) of information represented as the quantum state switching patterns of surrounding quantum particles, a person survives the demise of the physical body.
So we have life after death because the software is still preserved, but it is not able to influence physical reality the same way because the hardware of a corporeal body is missing. But the fluctuations of the quantum states of subatomic particles may be able to influence the brain activity of a living person(by passing on those fluctuations from the subatomic particles surrounding a person to those making up the person etc) So this INFORMATION(OR SOFTWARE) GHOST can, among other things, cause you to HALLUCINATE a more classical ghost sighting or experience. Thus, if you see Marie Antoinette somewhere in the Versailles palace, the physical image is unreal, but you REALLY hallucinate it, the activity in your brain is exactly as if you actually did see Marie Antoinette. Furthermore it is not your brain playing tricks on you but itself being tricked into certain states by deceptive outward stimuli. Thus the ghost itself is OBJECTIVELY REAL - software stored in the form of quantum fluctuations of subatomic particles which can influence brain activity causing you to hallucinate ghosts in more familiar forms such as touch, sight etc. Only the physical form we subjectively experience is an illusion. So we can in fact reconcile objectively existing ghosts with conventional thermodynamics! What do you think?