Virtually all cultures contain independent accounts which describe ghosts and spirits existing amongst the living. Across history, there have been many personal records that describe spirits and in more recent times, photographs and other forms of media have been used to capture (what is claimed to be) spectres on camera. Many cultures hold beliefs that the dead can communicate and interact with the living in the form as a ghost. [1] For example, in China, Vietnam, Malaysia, and Thailand, there is an annual ‘Hungry Ghost Festival’, where it is believed that ghosts are temporarily released to visit and interact with their living relatives, much like Mexico’s ‘Day of the Dead’ celebrations’. [2]

Some may argue that the existence of ghosts can be traced back to ancient religious texts and that those who believe in the paranormal today are influenced by their faith. Yet, it doesn’t seem that people’s beliefs about ghosts are necessarily rooted in religion. Although many religions speak of paranormal events, McDaniel states that ‘in places like Japan where secularism is very strong, the belief in ghosts is still high. Even hyper-modern and liberal Scandinavia has a high percentage of people believing in ghosts’. [3] The fact that so many individuals and collective cultures believe in the existence of ghosts, despite the wide range of social and religious differences between these societies, supports the notion that supernatural spirits do exist. Why would the presence of ghosts be a worldwide phenomenon that be traced back into the far history of almost all cultures if it was certain that ghosts aren't real?

The most obvious reason why people don’t believe in ghosts today is that there is limited scientific knowledge that can concretely support the existence of spectres. However, there has also been no scientific research that can outright disprove the existence of ghosts either. Hallucinations have been claimed to be responsible for “ghost sightings” by some. But, as both hallucinations and ghost sightings can only be described through an individual’s personal experience, only the person who witnesses unusual action can decide whether it is a trick of the imagination or if it is a true paranormal figure.

The existence of ghosts is also arguably able to be justified and applied to some scientific theory. Einstein’s theory on the conservation of energy determines that energy cannot be created or destroyed, but only transferred from one form to another. [4] Could it be that after we die, instead of our energy being transferred through the decomposition process, the energy remains but takes on the form of a spirit? With the overall lack of clear science which can undoubtedly disprove spiritual existence, it seems logical that there is a chance that ghosts can and do exist.

[1] ‘Why so Many of us Believe in Ghosts’, (https://theconversation.com/i-see-dead-people-why-so-many-of-us-believe-in-ghosts-148886)
[2] ‘Ghost Festival’, (https://www.newworldencyclopedia.org/entry/Ghost_Festival)
[3] ‘Why do People Believe in Ghosts?’, (https://www.theatlantic.com/health/archive/2014/09/why-do-people-believe-in-ghosts/379072/)
[4] ‘Conservation of Energy’, (https://en.wikiversity.org/wiki/Conservation_of_energy)

@annahubbard makes a good point, I'm just not totally convinced that ghosts aren't just a social way to explain the unexplainable. I don't necessarily mean hallucinations but in general events or experiences that humans don't have the words to explain or understand.

Im not closed off to the existence of ghosts, It'll just take more concrete science to convince me I think.

You posit a great argument Anna, and ghosts are a topic of great interest for me. I totally believe that ghosts (and the supernatural in general) exist, and this stems both from my belief that there is a world beyond death, and from my own research on ghosts and spirits. I do not think that ghosts are necessarily as they are represented in the movies, but maybe people that cannot really rest because of unsettling memories and trauma, this is why from the eighteenth century and forward ghosts have been directly linked to haunting a place where something terrible happened, or a person with whom trauma is associated. Many people have written books on the topic which can be called quasi-scientific because they try to explain certain phenomena or establish connections through the repetition of certain incidents, validated by personal accounts and historical facts. Catherine Crowe's 'The Night-Side of Nature' (1847) is but one example of the answer to people who try to cast ghosts away scientifically and dismiss them as figments of a diseased imagination. It is remarkable how many accounts of ghost sightings and hauntings there are, and I have recently read a book called 'Ghosts of Malta' which explored the haunted histories of certain places in Malta. I was astounded by the way the accounts of people who did not know each other matched, and how they also matched descriptions of hauntings recorded in eighteenth and nineteenth-century texts. Ghosts and haunting refer to something very personal and intimate, whether it is a person, place, memory, this is why it is so hard to validate scientifically, and should not be seen through the lens of science. Haunting is something that comes from within and is different for different people, and I like the way this is explored in series like 'The Haunting of Hill House' and 'The Haunting of Bry Manor', where you are almost not sure whether what people see are actual ghosts or their own trauma manifest in front of their eyes. Either way, haunting is something that is worth exploring from a psychological, social and political point of view (see Jacques Derrida's 'Specters of Marx' for a political interpretation of haunting) to see how people deal with their past and their own phantoms.

I completely agree that ghosts exists. Since I was a child I have seen spirits whether it be people standing by my bed, or a person/animal standing next to me as I leave a building. Whilst there is no concrete scientific evidence, for me the only thing that explains the things that I see is that they are spirits/ghosts.

I do agree that there is a world beyond death and that ghosts are the soul taking the form of the body that was left with trauma or (as some people call it) 'unfinished business'. I do not believe the soul and being of a person or animal dies when the physical body does but goes somewhere that is probably completely out of a humans ability to imagine. However, some souls are still stuck on earth for whatever reason meaning that they are the embodiment of the body they left behind.

Anna makes a strong case for the existence of ghosts. It is interesting that there are ghost stories throughout generations of history. It is difficult to imagine that these stories are just made up.
However, I personally can't help to be slightly sceptical. Could ghosts just be a vivid and greatly desired creation of the human imagination? It is a traumatic and terribly upsetting situation for anyone to lose a loved one. Ghosts perhaps offer some comfort to people that they have not completely lost their loved ones. That could explain why ghosts are so widely believed as the idea of their existence provides so many people with hope.
I also think that ghost stories are invented / exaggerated for the simple purpose of entertainment. Their stories easily capture an audiences interest, therefore they provide a easy form of making a profit e.g. through ghost tours / selling of ghost story books.
The denial of ghosts is not a denial of the afterlife. I believe in Einstein's theory about the transmission of energy. But, for me I just do not believe that the energy transforms into a 'ghost' that haunts our lands.

Ghosts don't exist - at least, there has never ever been any corroborated proof of their existence.

What there is lots of scientific evidence for, however, is our brains' capacity to 'see' them. It is called the sensed-presence effect and is very well documented. Michael Shermer (who wrote 'The Believing Brain') does a good write-up of the research here.

TL;DR - Although there might not be solid evidence and a lot of mixed reviews doing the rounds, it is clear that there are other 'elements' out there in the world. That is to say, ghosts do exist.

While Benjamin Radford a writer for livescience.com very astutely points out that there is as yet to be a universally agreed upon definition of what exactly a ghost is, the Merriam Webster dictionary defines the word ghost as a disembodied soul and the word spirit as a supernatural being or essence, for example, a soul. So these two words then can be used interchangeably.

According to the website The Psychology of Extraordinary Beliefs, stories of ghosts can be dated back to as far as Mesopotamia and ancient Greece. Apparently, the belief of whether or not ghosts/spirits do exist is based uniquely on one’s personal experience, as well as, influenced by one’s religious beliefs. This has to be true, otherwise we would not have such varied opinions on unexplainable phenomenon such as this.

Joshua J. Mark who is a freelance writer and co-founder, editor and direct of Ancient History Encyclopedia, mentions that these ancient civilizations believed in life after death. He goes on to say that while there are variations in details concerning ghosts/spirits and the afterlife in general, there is also a constant belief tied in to all of them. That being that the afterlife does exist which therefore means that ghosts/spirits do exist. I mean, what else would exist in the afterlife? It has to be something of the supernatural or 'other worldly' nature. And ghosts/spirits definitely qualify as something of the supernatural or 'other worldly' nature.

Another website, physicsworld.com explains the existence of ghosts from a scientific standpoint using Albert Einstein’s first laws of thermodynamics which states that, energy in the universe cannot be created or destroyed. It can only change from one form to another. Therefore, when someone dies their energy must (still) be present or “alive” in some way and this energy manifests itself into the ghosts/spirits that we’ve come to know and hear about.

Radford also makes mention of Albert Einstein’s theory suggesting a scientific basis for the existence of ghosts. What's more, he also agrees with physicalworld on the difficulty that science presents in accurately evaluating ghosts, in that there are such a wide variety of phenomena and so many theories that are linked to them.

The website countryliving.com also commented on this difficulty agreeing that while science cannot confirm or deny the existence of ghosts (as there is so much information and evidence floating around but nothing concrete to back it up), conversely it can pick up on psychological and physical factors one might experience during such an experience.

Overall, it has become clear to me that the very many theories and ideas that science has presented thus far regarding this phenomenon does not hold real merit. Especially as the world around us cannot be adequately explained yet and there is a spiritual aspect to life that we cannot at this point in time fully comprehend.

Therefore, just because one school of thought (and various other religious beliefs, cultures, etc.) cannot adequately explain the existence of ghosts/spirits does not mean that they do not exist.

Sources:

1. Definition of GHOSTS
   https://www.merriam-webster.com/dictionary/ghosts [accessed January 21, 2021].

2. Are Ghosts Real? — Evidence Has Not Materialized
   https://www.livescience.com/26697-are-ghosts-real.html [accessed January 21, 2021].

3. Mark J. Ghosts in the Ancient World
   https://www.ancient.eu/ghost/ [accessed January 21, 2021].

4. Are Ghosts Real? We Got to the Bottom of the Age-Old Question https://www.countryliving.com/life/entertainment/a34432856/are-ghosts-real/ [accessed January 21, 2021].

5. Ghosts: Fact or Fiction?
   https://u.osu.edu/vanzandt/2019/03/21/ghosts-fact-or-fiction/ [accessed January 21, 2021].

6. Is anybody there – science and the supernatural
   https://physicsworld.com/a/is-anybody-there/ [accessed January 21, 2021].

TL;DR: There are scientific reasons to explain 'paranormal' activity.

I'm not saying that weird things don't happen, but I don't think that this is due to ghosts or paranormal activity. For example, [Science News For Students] (https://www.sciencenewsforstudents.org/article/science-ghosts) argue that there are a lot of scientific reasons for people's supposed ghost sightings.

Examples include things such as [sleep paralysis] (https://www.webmd.com/sleep-disorders/sleep-paralysis#:~:text=Sleep%20paralysis%20is%20a%20feeling,or%20a%20sense%20of%20choking.), which happens when the brain 'messes up' the process of falling asleep or waking, which causes you to have vivid hallucinations that are very realistic.

Other examples include misperceptions, such as seeing things that aren't there, such as seeing a face in the shadow. Psychologists say that this happens to everyone at some point, but some turn to ghosts for explanations.

[Professor Brian Cox] (https://www.express.co.uk/news/weird/1042786/brian-cox-do-ghosts-exist-lorraine-kelly-large-hadron-collider-lhc) further argued that the Standard Model of Physics does not allow for the substance that can carry information after death that would not be detected by the Large Hadron Collider. The Standard Model of Physics states that if energy is lost it requires energy to move or emit light, so by this reasoning, ghosts cannot exist.

So whilst I think that ghost stories and horror movies are very enjoyable to watch and fun to theorize about, I don't think that they are actually real.

I wouldn't call them ghosts but spirits, and they have been seen by many everyday people who are considered well adjusted. Humans aren't the only beings in this Universe

Finding evidence for ghosts is somewhat problematic. There are, though, recent end-of-life cognitive lucidity studies that are causing some to suspect that consciousness can survive death, which would leave open the possibility for ghosts.

• There seems to be a problem at the heart of the search for ghosts: As writer Benjamin Radford puts it for an article on Live Science, "Either ghosts exist and appear in our ordinary physical world (and can therefore be detected and recorded in photographs, film, video and audio recordings), or they don't. If ghosts exist and can be scientifically detected or recorded, then we should find hard evidence of that — yet we don't. If ghosts exist but cannot be scientifically detected or recorded, then all the photos, videos, audio and other recordings claimed to be evidence of ghosts cannot be ghosts."

• Recent studies on end-of-life cognitive lucidity have revealed that consciousness, at least in some cases, appears to continue after biological death. Dr. Sam Parnia tells Robert Lawrence Kuhn on Closer To Truth that patients who were resuscitated hours after their deaths---after their brains ceased functioning---have provided scientific evidence that consciousness continues during those few hours, in the form of oftentimes-corroborated-evidence of conscious experience during their time being biologically dead. Whether it continues after three, four, five, and so on hours is not at this time knowable, but Parnia (and others) believe that the evidence for continued consciousness during the first few hours after someone would normally be declared dead is there.

• Personally, I spot at least two potential problems with this: 1. Maybe the resuscitated patients are remembering something that happened prior to their death, and thinking, once they've been resuscitated, that that experience happened when they were dead. Or 2. Maybe we just can't detect that there still is activity in the physical brain during these hours of death, but it's nonetheless there.

• Regardless, Parnia's research on resuscitation and cognitive lucidity in death is fascinating. I recommend reading this article/interivew, from which I have pulled the following three paragraphs:

"Recently some researchers have started to raise the question that maybe your mind, your consciousness, your psyche, the thing that makes you, may not be produced by the brain. The brain might be acting more like an intermediary. It's not a brand new idea. They have argued that we have no evidence to show how brain cells or connections of brain cells could produce your thoughts, mind or consciousness.

The fact that people seem to have full consciousness, with lucid well-structured thought processes and memory formation from a time when their brains are highly dysfunctional or even nonfunctional is perplexing and paradoxical.

I do agree that this raises the possibility that the entity we call the mind or consciousness may not be produced by the brain. It’s certainly possible that maybe there's another layer of reality that we haven't yet discovered that's essentially beyond what we know of the brain, and which determines our reality.

So, I believe it is possible for consciousness to be an as of yet undiscovered scientific entity that may not necessarily be produced by synaptic activity in the brain." --Dr. Sam Parnia

• Note: The second paragraph of the above quote is where I personally find there could be issues for scientific certainty, namely the 2 problems I mentioned above: Perhaps what we think is "nonfunctional" in terms of brain activity is actually lowly active in a way that defies current (or potentially ever possible) forms of measurement. And, second, maybe the "memory formation" from that time of death is not actually a memory formation from that time death, but instead a brief, dream-like experience people had before they fully died, which they then, after they're resuscitated, imagined to have occurred during those next hours after their death and prior to their resuscitation (the "full" death.) Dreams can, after all, feel quite long, even if they're in reality fairly short. And it seems possible that a resuscitated brain could be confused about the timeframes of events, considering it was potentially literally gone out of them, excluded from these timeframes in the heaviest way it ostensibly can be, for a period of time.

• Nevertheless, any evidence for continued consciousness after death is, of course, quite intriguing.

I believe that there are those that are more sensitive to spirits and have experienced them. I have on a few occasions seen people or felt people that I have known and have passed. It has not happened for quite a while though. I understand the skeptics because that is the reality of their world and they choose not to believe. It is not my place to convince someone who is not willing or cannot be open to the possibility.