Paranormal and Science Theories
Ghosts and magnetism
There is a popular paranormal theory that ghosts produce magnetic fields when they appear. There are several objections to this theory. Undoubtedly the most important is that there is no obvious evidence to back it up (unless someone out there knows different - please get in touch if you do). Until it has been persuasively demonstrated that a magnetic field appears whenever a ghost is seen, the theory is little more than speculation.
Even if a carefully controlled study (see right) does demonstrate a link between ghost sightings and magnetic field disturbances, it would still be necessary to decide whether it is cause or effect. It has, for instance, been shown in the laboratory that certain magnetic fields can induce hallucinations in some people (see MADS). So, it is possible that the appearance of magnetic fields is actually stimulating hallucinations of ghosts rather than that ghosts are producing magnetic fields.
One argument sometimes quoted against the idea that ghosts produce magnetic fields is that those proposing the theory don't explain exactly how ghosts can produce such fields. This is really an argument that the theory is incomplete (and definitely not scientific) rather than that it is incorrect. If it can be shown that ghost do produce magnetic fields then it is up to science to explain it. It is science's job to explain observations, not dismiss them out of hand.
A scientific theory must explain whatever reliable observations are available and make testable predictions about things that have not yet been recorded. This is crucial because there could be many competing theories explaining an observation. The only way we have to decide which is true is to do tests based on predictions from the competing theories.
So, if a theory predicted that the magnetic fields accompanying the appearance of a ghost would always be of a specific frequency and duration, this could be looked for to see if it was correct. To do this, the theory would have to explain how ghosts produced magnetic fields.
What people commonly call 'paranormal theories' are not the same as scientific theories. They don't usually explain things in terms of existing knowledge nor do they generally make testable predictions. They are usually too vague to be of any practical use.
Evidence, not assumptions
Many 'paranormal' theories contain assumptions for which the evidence is contested or non-existent (eg. 'ghosts are spirits'). Scientific theories, by contrast, always start with demonstrable evidence and then try to account for it.
In many cases the 'well known facts' on the paranormal are derived more from very old or even legendary cases rather than recent, scientifically investigated ones. Thus, the 'stone tape theory' may be attempting to explain evidence which simply isn't there and doesn't therefore require explanation.
Therefore, your first task in producing a theory is to assemble a body of evidence collected with appropriate scientific methods.
While it is fun to go 'ghost hunting', such expeditions rarely produce scientifically useful evidence. To do scientifically meaningful research you need to consider controlled studies.
A controlled study is one which tests a specific idea, like 'ghosts produce magnetic fields'. To do this, you need to control all the other variables that might otherwise influence results (hence 'controlled').
The first point to bear in mind is that you're going to need a lot of results. A few results all pointing in the same direction could just be a coincidence. You'll need a statistically significant sample of observations. So, unfortunately, you'll need to a bit about statistics and whole a lot of data.
Of course, you could take the results of other people's observations and analyse them together statistically. However, a major problem with this is is that the standards of investigation in our field is extremely variable. How do you know whose data to use?
In addition, you need to define what a ghost sighting is. Is it a human figure seen by at least one witness? Would someone hearing a 'person who wasn't there' count? Would you take into account how thoroughly the investigators checked for natural explanations before accepting it?
Then there's the matter of the magnetic fields. Would you take into account what kind of EMF meter was used (particularly the accuracy and sensitivity)? How close in time would a disturbance in the magnetic field need to be for it to be considered a 'hit'? And how big and for how long would the disturbance need to be to be counted? How accurate would you need the readings to be?
All these questions, and many others, would need to be decided in advance. And you'd still be left with the sticky question of deciding cause and effect (see left).
Is a theory required?
How do you know if a paranormal theory is required? Ask yourself, for how many well documented, scientifically investigated cases is this theory the best explanation?
No natural explanation
Paranormal investigation is a thankless task. It works, essentially, by trying to demonstrate that there is no natural explanation for an observation. So, if someone sees a ghost in their house, if you can prove they were alone and that there was no physical, physiological or psychological reason why they should hallucinate a ghost, it must be paranormal. In theory!
It's not that simple. How do know that there isn't another natural explanation that you simply haven't thought of and tested? How do you know that there isn't another natural explanation that science hasn't yet discovered? The obvious answer is, of course, that you don't. How can you?
So if you've eliminated all the obvious natural explanations what are you really left with? It might be tempting to say, the paranormal. But really, all you are saying is that the explanation is 'unknown'. The paranormal is, after all, 'beyond normal'.
Some people claim that the paranormal is beyond scientific enquiry. However, there are excellent reasons for thinking this is not so. If you find something you cannot explain, you can label it 'paranormal' if you like but really it is simply 'not explained yet'. So it would be premature to account for it using a paranormal theory.
Scientific case study
The Orb Zone Theory presents a case study of how the scientific method can be applied to paranormal phenomena.