Many people think that it is too narrow-minded to dismiss the existence of supernatural entities as ghosts. They rely on the famous aphorism that absence of evidence is not evidence of absence. I do, however, think that this aphorism can be misleading and can be used to justify the existence of claims born out of low intellectual effort. For instance, the concept of a ghost is built such that it must evade the boundaries of existing science and it will always continue to do so by retiring to any leftover scraps of human ignorance. The people who will assert that these things exist or even the less fervid ones who will only acknowledge the possibility of their perhaps existing have no good basis onto which that assumption could even be lent any sort of seriousness to begin with, other than follow science to its current limits and then inject their entities onto which lies ahead. Effectively, in doing this they are shielding their arguments from any sort of scientific appraisal and absolving their superstitious ideas from the very thing that would hold them into account, reason. It is this evasion of intellectual responsibility that constitutes the edifice upon which their claims can only persist to exist.
By definition, ghosts are spiritual remnants of a deceased individual. They do not possess material presence but do possess some sort of conscious operation. To presume that they exist would mean to have to suspend the laws of thermodynamics. Energy cannot be created or destroyed, but it can only change from one form to another and matter and energy eventually disperse towards maximum disorder. Indeed, our biological systems are governed by these laws. Energy from the sun is used by enzymes to form high-energy bonds in our living cells. Cellular respiration uses chemical bond energy to do work and give off heat in the process. A continuous flow of energy maintains such systems. We are, accordingly, energy-processing devices that act to temporarily preserve order. Gradual loss of order ends with death.
The existence of ghosts would contravene the laws of thermodynamics as ghosts would need a source of energy and even then, energy would have to be added to maintain order and structure. Ghost believers try to circumvent that by presuming the existence of some sort of metaphysical emotional energy which again, like all sorts of occult pseudoscience and pseudoscientific thinking, is designed such that it cannot be tested by laboratory experiments and empirical abstraction. Designed such that it cannot be tested period. Thus, we have no way of determining whether such a thing exists. Again, it has no observable consequences and cannot be tested. And, it is nonsensical because any form of energy, in accordance with the laws of thermodynamics, must eventually dissipate and thus would not allow for the persistence of ghosts which are thought to be immortal spirits.
Why then should the entity of ghosts be immune from the laws of thermodynamics? Do ghost believers have any evidence that they are indeed immune from the laws of thermodynamics? It is paradoxical to accord ghosts a naturalistic property (e.g. existing) and then in the same light, take away the naturalistic property of being an energy-processing device which the laws of thermodynamics require any existing entity to be. A ghost that dies or dissipates is, by definition, an oxymoron.
The next thing ghost believers tend to do is accuse the rational minded of stifling scientific progress by claiming that their prejudice against the possibility of these entities existing damages the progress of our understanding of nature. But, I think it is a hugely false equivalence to compare dismissal of supernatural phenomena with prejudice against a possible scientific hypothesis. No scientific hypothesis that has ever succeeded originated in this fashion and by the utilization such tactics. One would contest that ghosts even qualify as a hypothesis, to begin with, rather than some blatantly emotionally driven imagination just willed into existence. The concept of a supernatural claim relies on the notion that it must remain unexamined (opposite of what a hypothesis is) and the premise of the concept itself is that it cannot and must not remain remain examined by our natural means. The concept only survives by virtue of this notion and persists by virtue of this notion. I think the term “supernatural” itself is also a non-word because consequent scientific discoveries, for instance like gravity, atoms, etc were never really initially outside the bounds of the natural such that reason could not have accounted for them. All of these scientific phenomena that we were later yet to be discovered were only waiting to emerge outside the non-existent non-realm of the paranormal to which they were mistakenly ascribed and into the domain of the normal when our understanding of the natural world grew. I think the concept of the paranormal in this case becomes nonsensical seeing as it requires the unattested and unreasonable assertion that there are specific limits to what we could have ever understood when, in reality, our understanding of nature was always just limited and waiting to subsume the hitherto undiscovered phenomena into the natural.
Whatever science discovers and keeps unraveling, the superstitious will continue to put their entities outside where science is yet to tread and will tell you or “We still don’t know” or that “Science may not ever reach thus far because it is limited and there are other ways of knowing”. Yet, as science goes on and expands forwards, these claims can only continue to recede while relying on existing by virtue of the claim that science is yet to unravel things or by virtue of the claim that these entities exist outside the natural world such that we can never detect them. The pure definition of evasion.
Further, a lot of discoveries in science are usually made when one is not even look looking for them. Humans usually don’t have the foresight to actually forsee or predict a discovery. The shortsightedness of the human mind is largely oblivious as to the breadth of nature’s imagination. If the development of science has shown us anything, it often takes serendipitous occurrences and one’s keen observation of natural phenomena to discover a lot of things in science, which later end up very much confounding our intuition (e.g. Einsteinian relativity). Our imagination, for the most part, is always anthropocentric and usually not even the right picture. The answer for what lies ahead will be something entirely different and will be counterintuitive in a way that we could never even currently imagine. One cannot just say that just because one is imagining something, that this should gain an immediate accession into the world of scientific theory. A claim advanced must be underlain by robust epistemology rather than etched onto a severe form of intellectual flippancy. As Sherlock Holmes once said, there is this scientific use of the imagination. To just imagine something whatever it may be and claim that it must be true constitutes poor philosophical method.