Affirming The Consequent In The Search For Ghosts

Ghost meterSuppose – just for argument’s sake – that ghosts are real. And suppose, again, that when a ghost is in your vicinity, it affects the magnetic field around it.

Now imagine you are on a ghost hunt, run by one of the hundreds of ghost hunt companies that exist – those commercial enterprises that claim to take you through a haunted location to find evidence of the paranormal. An overnight vigil, perhaps. You pay money to go on a ghost hunt, and you are offered the use of scientific instruments in your pursuit of the supernatural.

Scientific, remember.

One of the scientific instruments you might use is an EMF (Electro Magnetic Field) detector. They seem to be very popular within the ghost hunting fraternity. So, assuming that ghosts are real, and that they affect the magnetic field in their vicinity, a basic logical proposition can be formulated:

If there is a ghost present, then there will be a variation in the local magnetic field.

So, you set off in pursuit of ghosts, and after a short while, the needle on your device’s dial flickers and moves to a point showing a definite magnetic anomaly. Bingo! You’ve found a ghost. Or have you?

Numerous paranormal “experts” will quite happily tell you that there is a “theory” that the presence of ghosts will give readings on EMF detectors, and so if you get such a reading then it is indicative of a ghostly presence. It’s logical, isn’t it?

In fact, no, it is definitely illogical – a non sequitur, as it happens. I’ve assumed for the above scenario that ghosts are real. If they were, and they did cause magnetic anomalies, then it would be true that a ghost in the area would cause a deflection of the needle (or flashing lights) of your EMF device. But the fact that a magnetic field can change (or just be there) does not indicate, logically, that a ghost is present (even assuming that ghosts exist).

This logical fallacy occurs in formal logic when it is assumed that if particular premises imply a particular conclusion, then the conclusion also implies the premises.

The logical form alluded to above is called Modus Ponens. It goes like this:

If P, then Q.

P, therefore Q.

For “P” read, “A ghost is present.” For “Q” read, “There is a magnetic anomaly.”

In formal logic, the above is called a valid argument because the conclusion necessarily follows from the premises. (Strangely, however, neither the premises nor the conclusion of a valid argument have to actually be true in the real world; the important thing is that the conclusion follows from the premises. I’ll come back to that later.)

So if a ghost causes a magnetic reading, why can’t you take it that when you get such a reading that a ghost is around? The simple answer is that there are lots of things that can cause magnetic fluctuations. In any modern building (and old ones), you are literally surrounded by magnetic fields. Electrical wiring is all around you, so it just takes someone to operate an electrical light or appliance somewhere nearby to cause a fluctuation that can be measured. Metal objects nearby will also affect a magnetic field. Anything with an electric motor, especially, will do the same. Even if a ghost could affect a local magnetic field, there are many other possible causes as well.

In short, a magnetic variation can have numerous different causes, and there is no way to tell what, in particular, is causing the altered reading.

The fallacy is called “affirming the consequent.” It’s quite common, in fact. On a mundane level, try this:

If it is raining, then the ground is wet.

It is raining, therefore the ground is wet.

Modus Ponens, and valid reasoning to boot. But if someone came indoors and told you that the ground is wet, should you conclude that it is raining? The simple answer is no, you shouldn’t: you can easily think of several reasons why the ground might be wet without the need for rain. A burst water main, perhaps, or your neighbours are watering their gardens, and anything else you can think of.

If the ground is wet, it might, indeed, be raining, but it might be something else. The fact that P implies Q does not mean that Q therefore implies P. (There is an exception to this rule when a logical argument is also a biconditional – another post for another day.)

A similar thing happens in other aspects of paranormal research. ESP researchers spent decades trying to prove the existence of telepathy – quite often with the use of Zener cards. Essentially, a potential psychic is presented with series of cards, each of which have one of five possible symbols printed on it. Over a series of tests, the psychic’s task is to identify by psychic means the symbols as they are drawn randomly. Pure guesswork should give results that align with chance expectation; psychic abilities should enable the psychic to identify significantly more than would be expected by pure guessing.  The reasoning among psi researchers has tended to go (If P then Q):

If ESP is at work, then the (statistical) results will deviate from chance.

The results deviate from chance.

Therefore, ESP has been confirmed.

Unfortunately for the believers, there are many other reasons why the results of psi tests might deviate from chance – none of which has anything to do with the paranormal, including poorly designed experiments – anything from poor experimental controls to the great bane of paranormal research, outright fraud. Like the examples above, the assumption is that if the premises imply the conclusion, then the conclusion must imply the premises. But it just ain’t so.

The first sentence of this post was, “Suppose – just for argument’s sake – that ghosts are real.” And that is where the problems start. So-called ghost hunters assume at the outset that ghosts are real entities – immaterial, maybe, but the assumption is that they are real, nevertheless. But no one has actually demonstrated that ghosts are anything other than wishful thinking on the part of the believers. There is no confirmable, testable evidence that ghosts exist (whatever your definition of a ghost might happen to be). How do the experts know that ghosts (if they exist) affect magnetic fields anyway? The short answer is that they don’t.

EMF detectors are useful for detecting electromagnetic fields, and there is no reasonable doubt whatsoever that the electromagnetic spectrum is real. Electric motors, for instance, could not exist otherwise. Electromagnetism from the far ultraviolet, through visible light to the far infrared is a reality and all of it can be demonstrated scientifically.

Ghosts, on the other hand, are a made-up idea to explain phenomena that sometimes do not have an obvious or demonstrable explanation. If you find an electromagnet field with your EMF detector while you are looking for ghosts, so what? You will have found an electromagnetic field, alright, but why should anyone think that a ghost is causing it?

As I said earlier, neither the premises nor the conclusion of a valid argument need to be true in the real world. Think of the characters in a novel, for instance. For a story in a novel to work, all of the elements have to have a clear logical relationship to each other, even though the characters, places and events don’t exist in the real world.

If Merlin is a wizard, then he can perform magic.

Merlin is a wizard, therefore he has magic powers.

That’s fine in the context of the story of King Arthur even though the characters in the story are nothing more than myth, at best. But in the same story, a character that has magic powers is not necessarily Merlin. The fact that Morgana has magic powers does not make her Merlin.

The essential point to keep in mind in all of this is the form of logic that appears in an if/then scenario. It is “true” that if Merlin is a wizard then he has magic powers – at least in the sense that the conclusion follows from the premises – even though Merlin is not a real person, and magic is nothing more than fantasy.

It cannot be said too many times that it is the relationship between premises and conclusion that is important. For a conclusion to be true in the sense of being real, then the premises also have to be true. Before it can be claimed that ghosts affect magnetic fields it is first necessary to demonstrate that ghosts are real, and then show how it is that ghosts affect an electromagnetic field. Until someone can do that, you can be sure that EMF detectors are a complete and utter waste of time and money for anything other than the job they were designed for.

I assume that the people who run these ghost hunting expeditions do believe that ghosts are real and that they can be detected by electronic gadgetry with dials and blinky lights and so on. I also assume that they have no understanding of basic logic.

The bottom line.

Modus Ponens is part of formal logic, and is also known as deductive logic.

The conclusion must follow from the premises for the argument to be called valid.

The premises of such an argument imply the conclusion, but the conclusion of that argument does not imply the premises.

If you do happen to go on a ghost hunt and you use an EMF detector, just keep in mind the fact that you might be able to detect magnetic fluctuations, but those fluctuations tell you absolutely nothing about the existence or presence of ghosts or anything else allegedly paranormal – even if ghosts were real (and I’m pretty sure they aren’t).

Using EMF detectors to find ghosts is nothing more than pseudoscience, but the assumption that you can detect ghosts with such a device is just bad thinking. If your ghost hunting host tells you that an EMF detector is useful in any way for detecting ghosts, ask him if he knows what the logical fallacy affirming the consequent means. At least you know what it means – now.

Just for fun:

Here is a logic puzzle for you to try if you want to. It is a basic puzzle that will probably be familiar to people who have studied logic, but anyone can have a go at it. I’ll wait to see if anyone wants to try it and put their answer in the comments (with the reasons for their conclusion). In a couple of days, I will post the actual answer in the comments.

Here we go:

In the next street to where you live, all of the houses on one side of the street are bungalows. On the other side of that street, all of the houses are detached houses.

Here’s the funny thing: the people who live in the bungalows always tell lies.

The people who live in the detached houses, however, tell only the truth.

One day, you meet three men who live in that street. Let’s call them Tom, Dick and Harry. After the initial meeting and introductions, you ask Tom, “Do you live in a bungalow or a detached house?”

But Tom mumbles something you can’t hear. So you ask Dick , “What did Tom say?”

Dick replies, “He said he lives in a bungalow.”

Harry immediately turns to you and says, “Don’t believe Dick, he’s a liar.”

The question is: does Harry live in a bungalow or a detached house?


11 responses to “Affirming The Consequent In The Search For Ghosts

  1. Very Good! But what if you start to use an EMF meter as a means to communicate and as you say “ghosts, if they exist”, manipulate this device as per the investigator invitation in order to provide accurate answers to the guestions being asked. When this occurs during a Paranormal Investigation and a Parapsychologist observes closely the 95% accurate answers and states on a number of occasions on the film that the experiment is pretty conclusive. Certainly this warrants further investigation. But this happens on ALL our investigations bar one. Be your own Judge …. This video is raw and unedited. Its 40 mins long and has 30 mins of communication with “An intelligent despondent”. The experiment demonstrate whatever it was, It could hear my voice, Understand my voice, could see, could guess the age of one investigator. See for yourself


  2. Thanks for commenting.

    I think you’re being a bit too confident when you say that your video footage is “conclusive,” for the very reasons I gave above: the logical fallacy, affirming the consequent.

    I’ll state it this way: If a ghost can communicate through an EMF device, then the device will react to a ghost’s communication.
    But the fact that the device reacts does not mean that a ghost is communicating. I can think of other reasons why the device might react, but those reasons have nothing to do with ghosts. You will first have to prove that ghosts are real and can communicate through an EMF detector, but even then, it could still be something else causing the readings.

    The interesting thing about the video, of course, is that the device appears to respond to questions posed to the entity that is supposed to be present. But there are still other possible explanations for what is happening.

    I’ll say here that when I communicate with pro paranormal advocates I always work on the assumption that they are honest people who are genuine and sincere in what they believe, so please don’t think that I am accusing anyone in your team of fraud. I never do that, but I can’t rule it out either. I just suspend judgement. As a sceptic, I can only claim that I just don’t know what is going on.

    I watched the video, and I can see why many people would be impressed. But all I have to work on is what I saw in the video – questions being asked and the EMF device apparently reacting. I can’t test the setup you had, or examine the device used, or go around to see whether anyone is operating an electrical device that would give readings on demand, whether the device itself had been rigged in some way, or any number of other possibilities. As I say, I’m not accusing you of a hoax, but how can you be sure that someone else is not hoaxing you?

    I see in the video comments that the alleged entity – named as “Charlie” does not want to be identified because it doesn’t want its living relatives upset. Sounds fair enough, but that is just another avenue of investigation closed off. Contacting those relatives and finding confirmatory evidence of anything “Charlie” reveals would be helpful, but obviously any potential independent investigator can go no further with it. Some people will take that claim on faith, but it’s still an investigative dead end.

    Unfortunately, the video did not show anything that could be described as scientific: a group of people asking questions in a dark room and apparently getting appropriate answers (sometimes with cheers and applause). I can’t fault the enthusiasm that is obvious in the group, but anyone with scientific training is likely to view the footage with a jaundiced eye. It is not conclusive of anything paranormal, and is just not scientific in any way.

    I’ll add one other thing. I cannot prove that ghosts do not exist or that an EMF device cannot detect them, so I tentatively put “ghosts” on the “list-of-possible-causes,” along with everything from incidental influences to hoaxes and fraud. I don’t even mind if anyone can prove the existence of the paranormal (that would be pretty cool, and I would not begrudge anyone their Nobel Prize for doing so). But the onus is still on the claimant(s).

    As you might guess, I am not convinced by what you think is conclusive. It isn’t.

    Best regards.


  3. The answer to the logic puzzle:

    You didn’t hear what Tom said, but that doesn’t matter – there is only one answer he can give:

    If Tom tells only the truth, then he lives in a detached house and will say so. If Tom tells only lies, then he lives in a bungalow but will tell you he lives in a detached house. Whether he lives in a bungalow or a detached house, he will say that his house is detached.

    Now that you know what his answer has to be, Dick tells you that Tom said he lived in a bungalow – so Dick must be lying.

    When Harry informs you that Dick is a liar (you’ve just worked that out), he has to be telling the truth. So Harry must live in a detached house, just like all the truth tellers.

    It also follows that Dick must live in a bungalow.

    As for Tom, there is no way (given the information supplied), logically, to tell whether he lives in a bungalow or a detached house. We’ll need a psychic to work that one out, I suppose.


  4. Ah ghost hunters are enormous simpletons, yes. Can’t handle seventh grade pre-algebraic logical equivalence. The Latin moniker will help tho, that makes the principle so much more comprehensible for the simpletons.

    And for the next predictive construct development peer white paper I review which challenges me, an excellent response will be “please don’t think that I am accusing anyone in your team of fraud. I never do that, but I can’t rule it out either. I just suspend judgement.” In fact, that will be my default response for all papers. I will be worshiped for my critical thinking prowess.



  5. Thank you for watching! It is impressive if you are open minded. it gives food for thought A certain amount of discretion was used not to identify the “Spirit”. Further investigation is ongoing by our own researchers and as we used the Name Charlie or Charles to protect the identity of anyone being contacted by any individual or organisation outside of the investigative team.

    All investigations are can be faked. But our team is a strong team. Why would we or anyone want to fake our results? We have only shown that video to a handful of relevant persons with a view to finding a logical answer to the 30 min session. To date no one has come up with a logical reply.

    A documentary was made of this investigation and an interdependent film maker reports in his own words. He even included a session for the Skeptics. That will be you!

    We like to regard ourselves as a very professional research team. We do not conduct Ghost hunts. We do not make any money! We use what devices we have available to us at the time. IF all devices are deployed and only one responds that it is only natural to document the results of all experiments conducted!

    I have been sensitive to spirit since i was very young! I do not expect anyone to believe me when I communicate with spirit as mediums do. But medium communication is one sided and hard to document. So in this experiment we used an EMF device to produce the results for all to see.

    The Gentleman referred to in the video as Terry is indeed a Trained Parapsychologist. He was there in a professional capacity and I can assure you that he was very thorough as were all the other skeptics in the room. He he says it is conclusive then I am going to imaging for one moment that he has done his job properly as he has done for over twenty years.

    If anyone was manipulating the device, it must have been a Skeptic. Like I said, My team put a lot of work into their reports.

    10 min independent documentary on the Secret Nuclear Bunker investigation with 30 min spirit Contact and fraud debunking!



  6. Ethical Skeptic,

    I didn’t say or imply that ghost hunters are any kind of simpletons. Distorting my meaning and presenting a caricature of what I said is a logical fallacy called a straw man. That’s not what I would call ethical.

    As for your sarcasm, it speaks for itself but it is not an adequate substitute for reasoned argument.


  7. North London Paranormal Investigations,

    Yes, I do think I am open minded; I’m not on a quest to disprove the paranormal. As someone once asked me, “Are you still trying to prove that psychics aren’t real?” My answer to such a question is always along the lines of, “No, I am trying to get them to prove that they ARE real.” There’s a difference.

    The documentary you pointed me to was interesting (and well produced, I thought).

    I didn’t detect anything that makes me think you are employing any fakery, although I can think of different ways that I would conduct such an experiment. Essentially, trying to prove a hypothesis is not the scientific way. Science goes ahead by trying to disprove a hypothesis. That sounds a bit counter intuitive, but if a hypothesis is false, then it’s necessary to find a way to prove that. There might be no limit to the number of things that support the idea of something paranormal, but it is only if a test can potentially disprove a hypothesis if it is, indeed, false, that it can be accepted as valid. Even then, failure to disprove the hypothesis can only be held tentatively as positive evidence until further research and, of course, replication can support it.

    It seems to me that the big problem with paranormal research is that there is no shortage of excuses for failure that can be – and always are – brought into play. “The psychic energy is weak.” “The vibrations are being upset by the presence of a disbeliever.” And so on. But this “psychic energy” has never been objectively detected, and the very idea does not fit in with what is actually known in physics about energy. Testing the paranormal is fraught with problems – even when a psychic fails an objective test, that does not prove in itself that he or she does not have those powers. Maybe it works for them other times. And maybe you can see why I am sceptical.

    I’m not going to try to give a “logical” explanation for what is going on in the videos, because I just don’t know the full set up; I can only guess what might be happening, but that’s all it would be – guesswork. The burden of proof is always with the person(s) who make the claim. I still don’t think the video is conclusive, but best of luck with what you are doing.


  8. After watching the Nuclear Bunker video, one thing that screams out is that not one question was posed in which the response could be measured in an objective way. Despite the excited claims in the video that ‘Charles’ was accurate, there were inconsistencies and errors. Charles even got the age wrong.

    An objective blind test of the EMF responses wouldn’t be too difficult to devise. In fact, there’s already a test which could be used – Deal or No Deal. Twenty-two boxes, each containing a blank sealed envelope. Inside each envelope, a piece of card with a different number on, randomly between say 1 and 100. Obviously each stage of preparing the cards, envelopes and boxes would be carried out by different independent participants. Since Charles has an astounding success rate of 95 per cent, then he should be able to accurately identify 20 of the 22 numbers in the boxes. The same test could be repeated several times, just in case Charles was having an off-day.

    I’m surprised that the trained parapsychologist hadn’t already thought of it.


  9. Brian,

    The experiment looks impressive insofar as questions are seemingly being answered by an unseen entity. And it was also demonstrated that a particular electrical device would not be able to create the results that were shown. (But what about any other devices?) As I said earlier, I don’t share the group’s confidence that their experiment is conclusive. Without further background information I would rather say it is incomplete. It remains to be seen whether they will release more details.

    You’re right, though, in the sense that any controls that might have been in place are not obvious or explained. Your idea for randomising the whole thing is – or should be – standard in an experiment of this type. If the parapsychologist involved has written up and published details of how the experiment was constructed and carried out then I would be very interested to read it.

    I am not going to be too critical, however. In fact, I applaud the group for being willing to reveal their evidence for public scrutiny. I can think of a couple of litigious amateur investigators of our acquaintance who would have threatened you and me with legal action by now for even suggesting that they show us their evidence.


  10. The bottom line is we are all seeking the same goal. As a group we are making a concerted effort to obtain proof of something. We learn from ourr mistakes and we also take onboard the comments. We are happy to share what we have and hope that one day and with enought expertise and controls in place, we can satisfy the most sceptical of sceptics.

    Our experiments have changed since then and we have devised other experiments using playing cards. We use a standard list of questions now which work on a flowchart statement arguement i.e. If “No” goto next question, if “Yes” go to question x.

    When ever we do an investigation, we always use a a member of the public to hold the equipment. It is them who start to get the responses. In each case, none of the Public have used an EMF meter before or aware of its functions.

    In this documentary, we have a medium who in our opinion was very good! She had no idea of the location and she had never worked with a team before. But her results were impressive. It’s a short one again but we do get these responses from 99% of our investigations.

    This is our investigation documentary from The Cage – Haunted witch prison –

    Again, I welcome your comments and I appreciate your honesty. With continued support we can come close to getting a few answers.



  11. NLPI,

    It’s interesting to know that you are modifying your experiments – that sounds promising – but the information you have given is pretty vague. For that reason, I can’t offer much of an opinion, and it probably wouldn’t be practical for you to give the full details here as a blog comment.

    The mini documentary was, again, well produced, but it raises more questions for me than it answers. I admit I tend not to be impressed when a historian is on hand to verify anything that a medium says; after all, if the history is there, then presumably it is available for anyone who wants to research it. That’s a loophole that needs to be closed.
    Also, a lot of people are milling about. That reduces the amount of control you have over the situation.

    Overall, I would say that what you have presented is entertaining, intriguing and gives food for thought. But without all of the information, i.e., a full write up of the experiments for critique, it’s still not conclusive.
    Instead of trying to “prove” the existence of a paranormal phenomenon, it would be better if you could prove that nothing else could possibly be causing the effects that we see. A process of elimination would make your experiments more credible.

    You’re up against it, though. Even the most famous and highly qualified researchers have failed to convince mainstream science that there is anything paranormal going on. They seem to get confirmation of their belief in the paranormal, but only in their labs; and no one else can ever reproduce their findings.

    In any case, there are as yet no practical uses to which these alleged psychic abilities are ever put. If remote viewers, for example, were routinely finding survivors in the aftermath of an earthquake then that would be convincing.

    Better still, if a newscaster could replace “Tonight’s lottery numbers were…” with “Tonight’s lottery numbers will be…” then no one would be able to deny it.

    I can’t see it happening, though.


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