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Disclaimer: The views and opinions expressed in this page are strictly those of the page authors. The contents of this page have been reviewed or approved by the Southwest Ghost Hunter's Association. All effort has been taken to maintain correct information at the time it was written. Some material may be dated and is archived within this section of our website. This article is copyright, 2009 by Cody Polston, Bob Carter and SGHA. All rights reserved.

 Articles ~ Skeptics Corner ~Using Critical Thinking and Scientific Method to analyze video

Critical thinking consists of mental processes of discernment, analysis and evaluation. It includes possible processes of reflecting upon a tangible or intangible item in order to form a solid judgment that reconciles scientific evidence with common sense. In contemporary usage "critical" has a certain negative connotation which does not apply to this specific case. Though the term "analytical thinking" may seem to convey the idea more accurately, critical thinking clearly involves synthesis, evaluation, and reconstruction of thinking, in addition to analysis.

Critical thinking is a form of judgment, specifically purposeful and reflective judgment. In using critical thinking one makes a decision or solves the problem of judging what to believe or what to do, but does so in a reflective way. Critical thinking gives due consideration to the evidence, the context of judgment, the relevant criteria for making that judgment well, the applicable methods or techniques for forming that judgment, and the applicable theoretical constructs for understanding the nature of the problem and the question at hand.

Critical thinking is important, because it enables one to analyze, evaluate, explain, and restructure our thinking, decreasing thereby the risk of acting on, or thinking with, a false premise. However, even with the use of critical thinking skills, mistakes can happen due to a thinker's egocentrism or incorrectly extending ones own belief system beyond its reasonable limits or failure to be in possession of the full facts. In addition, there is always the possibility of inadvertent human error.

Critical thinking is based on concepts and principles, not on hard and fast, or step-by-step, procedures. Critical thinking does not assure that one will reach either the truth or correct conclusions. First, one may not have all the relevant information; important information may remain undiscovered, or the information may not even be knowable. Furthermore, one may make unjustified inferences, use inappropriate concepts, fail to notice important implications, use a narrow or unfair point of view. One may be a victim of self-delusion, egocentricity or sociocentricity, or closed-mindedness. One's thinking may be unclear, inaccurate, imprecise, irrelevant, narrow, shallow, illogical, or trivial. One may be intellectually arrogant, intellectually lazy, or intellectually hypocritical. These are some of the ways that human thinking can be flawed.

Analysis principles

Ockham's razor

Ockham's razor (sometimes spelled Occam's razor) is a principle attributed to the 14th-century English logician and Franciscan friar, William of Ockham. The principle states that the explanation of any phenomenon should make as few assumptions as possible, eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory. The principle is often expressed in Latin as the lex parsimoniae ("law of parsimony" or "law of succinctness"): "entia non sunt multiplicanda praeter necessitatem", roughly translated as "entities must not be multiplied beyond necessity". An alternative version "Pluralitas non est ponenda sine necessitate" translates "plurality should not be posited without necessity".

This is often paraphrased as "All other things being equal, the simplest solution is the best." In other words, when multiple competing theories are equal in other respects, the principle recommends selecting the theory that introduces the fewest assumptions and postulates the fewest entities. It is in this sense that Occam's razor is usually understood. This is, however, incorrect. Occam's razor is not concerned with the simplicity or complexity of a good explanation as such; it only demands that the explanation be free of elements that have nothing to do with the phenomenon (and the explanation).

"Keep it simple."

The more variables that you had to your hypothesis, the harder it will be to replicate.


Reductionism is an approach to understanding the nature of complex things by reducing them to the interactions of their parts, or to simpler or more fundamental things. In analyzing video, this is crucial. The key to determining the nature of an object in a video is to establish it's relative and perceived positions. This can only be done by observing how the object in questions interacts (behaves) in relation to its environment (light sources, movement, etc.). This is often done by using a frame by frame analysis.

Relative Determination

Relative determination is a process to identify where an object actually is as compared to where it is perceived to be. In video analysis, this can be broken down into two zones, near field and far field. These zones are characterized by the observable behaviors that objects exhibit when they are in a particular zone.

Near Field describes an area that is very close to the lens of the camera (1" to 10" away from the lens). Take a 44 ounce cup and place it against the lens and you can see the approximate space that is being referred to. Objects in the near field may also be in the circle of confusion. As such, they generally have the following characteristics.

1.) Objects enter and exit from out of frame.

2.) There is no substantial change in the objects size.

3.) Objects are always in the foreground.

4.) Objects have little or no change in luminosity. They may fade in or out as they approach the camera's illumination source but are otherwise consistent.

5.) Objects in the near field may change direction but multiple direction changes are not common.

By contrast, the Far Field covers the remaining area (10" to infinity) and objects in this area will often have these characteristics;

1.) Objects change size based on it's distance from the camera lens.

2.) Objects interact within the environment (moving around or behind people and objects)

3.) Changes in luminosity are apparent. Objects are affected by light sources causing an increase in illumination or cast shadows.

4.) Multiple directional changes are common.

The Scientific Method

The final step is to utilize the Scientific Method.

  • Define the question (why is it thought to be paranormal?)
  • Gather information and resources (observe)
  • Form hypotheses (make several guesses)
  • Analyze data
  • Interpret data and draw conclusions that suggests your hypothesis is correct or serves as a starting point for new hypothesis

In general, you will form several hypotheses and allow the data from the analysis to guide you to the most probable hypothesis that explains the phenomena. It is also possible that the data may nullify all of your hypotheses and suggest a new one. The idea here is to allow the data from the analysis to lead you to the most correct answer and not bias your results by trying to "squeeze" the data into the hypothesis that you want it to be.


The last thing that needs to be explained before we begin is Underdetermination. Underdetermination (sometimes called indeterminacy of data to theory) is a term used in the discussion of theories and their relation to the evidence that is cited to support them. Arguments from underdetermination are used to support epistemic relativism by claiming that there is no good way to certify a theory based on any set of evidence. A theory (or statement or belief) is underdetermined if, given the available evidence, there is a rival theory which is inconsistent with the theory that is at least as consistent with the evidence. Underdetermination is an epistemological issue about the relation of evidence to conclusions.

Underdetermination can be divided into weak and strong underdetermination. To claim that a theory is weakly underdetermined is to say that the currently available evidence fails to prove it, but some evidence collected in the future might conceivably be able to. To claim that a theory is strongly underdetermined is to claim that it is fundamentally impossible to acquire evidence that could completely settle the dispute between the rival theories.

Another distinction is between deductive and inductive underdetermination. For two theories to be deductively underdetermined means that the available evidence does not completely contradict either theory. The case of inductively underdetermined theories is more problematic; not only are the theories compatible with the available evidence, but even attempts to determine which theory is better fail.

The possible combinations of these two distinctions yield four types of underdetermination, though by definition a case of weak inductive underdetermination admits the possibility of its own resolution into mere deductive underdetermination through the acquisition of future evidence, otherwise it would fall under strong underdetermination. In turn, it could be argued that it is impossible for a theory to be truly strongly, inductively underdetermined: it would have to admit absolutely no possibility of valid evidence in the favor of other theories or against itself, which would necessitate it not making any novel predictions, which in turn is a valid inductive argument against it (see Occam's razor).

Claims of weak underdetermination tend to center on what evidence happens to be available for some specific set of theories, while strong underdetermination often involves more general epistemological claims about what kind of evidence is possible or viable at all, either for a particular theory or for theories in general.

Strong underdetermination can also be inadvertently caused by the analyst. Assumptions should never be made as they may bias the data and render a false result. Use only verifiable information in the final formation of the hypothesis.

Now that basic principles have been explained, lets move onto some practical examples.

Example 1, Video from an abandoned hospital

We will start with the video on the left. It was presented as "paranormal" for the following reasons;

1. The object leaves a contrail as it moves towards the camera.
2. The object moves in multiple directions, unlike dust that tends to have a downward track.
3. The object vanishes mid-frame.
4. The object reappears (coming off of or out of the floor) just before the camera moves at the end of the video.

The first step is to gather information on the location, the camera and what is happening in the video.

Several facts are learned that will affect the analysis of the video.

The camera is a professional Sony camera (high resolution) that was augmented with a long range IR illuminator (Bat Light). This increases the visibility of some less obvious objects out to 300 feet.

The location has no open windows and the air conditioning is not operable. In the video, the group is leaving the third floor (going to the elevator).

Figure 1

The video is now broken down into individual frames and each frame is analyzed. Since relative determination provides data that will shape our hypothesis, we look for elements that indicate if the observed phenomena is in the near or far field.

The first observation is that the object in the video appears fainter and smaller as it enters frame. However it is larger and brighter before it vanishes out of frame for the first time (Figure 1). The obvious change in size indicates far field phenomena.

Observation 2; As the object crosses the light reflected on the wall, it becomes brighter. This shows an interaction with it's environment (illumination). This indicates far field as well.

Observation 3; During the objects trek, it changes it's shape and size dramatically (Figure 2). The object also appears to have a contrail effect. This is yet another indicator that the object is in the far field.

Observation 4; The object then exits frame, circles around and moves off, eventually vanishing in mid frame. While some movement changes can be found in near field phenomena, all of the movements plus the mid frame disappearance suggests far field phenomena.

So all the observations indicate far field phenomena.

The next step is to formulate several hypotheses on what the object may be. Because relative determination is an important factor, I will list which hypothesis are related to the near or far fields. We will then organize the hypotheses based on that set of data. In this way the data from the video analysis is pointing to the hypotheses that are the most correct.

Basically we are building a probability scale. Based on the available data, the most probable explanation will be listed first, the next probable below that and so on.

So our list of possible hypotheses will look like this;

1. Reflection of light (Far Field)

2. A flying insect (can be both Near and Far Field)

3. A dust particle (Near Field)

When I first watched this video, I was inclined to say that it was just simply a dust particle. However after the analysis, the data suggests that the phenomena is in the Far Field. A dust particle is a Near Field phenomena, therefore I must move that hypothesis to the bottom of the list because the data implies that it is the least probable.

Now we will use critical thinking to evaluate the remaining hypotheses and determine which one would be the most accurate or if a new hypothesis must be formed if the data is inconsistent.

1. Reflection of light

This hypothesis suggests that the object is light reflected on the wall from an undetermined object. This requires some knowledge of the physics of reflection. To simplify matters, the light is reflected from an interface between two media. The distance between the media dictates the intensity of the reflected light. The closer the distance, the brighter and more concentrated the reflected light is. The greater the distance, the fainter and more diffuse the light becomes.

Now we will look at our observations and see if they support the hypothesis.

Observation 1: Figure 1 shows that the object is brighter closest to the camera, this would indicate that the interface would be closer to that point. Since it is not visible in the video, the interface would have to be located out of frame. So this observation supports the hypothesis.

Observation 2: The reflected light on the wall should not affect the intensity of a reflected light. This observation is inconsistent with the hypothesis.

Observation 3: If the object is reflected light, its size and luminosity should change gradually as it moves across the wall closer to it's point source. However this observation shows dramatic changes in shape and luminosity, making it inconsistent with the hypothesis.

Observation 4: This observation is inconsistent with the hypothesis because the "reflected light" comes off the wall. It simply can't do that. Reflected light also lacks a sufficient explanation for the contrail effect and how the object vanishes in mid-frame.

The observed data does not support the hypothesis, so we move this one down on the list.

2. A Flying Insect

This hypothesis suggests that the object is a flying insect that flies towards the camera, out of frame, and then flies away from the camera.

Observation 1: Consistent with the hypothesis. The insect would grow brighter as it came closer to the camera's illumination source.

Observation 2: This observation is also consistent with the hypothesis. The insect would be illuminated more by the reflected light on the wall.

Observation 3: The hypothesis matches the observed phenomena. A flying insect would change size as it approached the camera and the position of it's wings could cause it to change shape. The contrail effect in this observation also matches a flying insect. This is due to the propensity of video cameras to produce characteristic stroboscopic artifacts when imaging rapidly flying animals, especially insects. This is a known phenomena that are often called "rods".

Observation 4: An insect could easily perform the movements in this observation. As for the mid frame disappearance, the insect leaves the frame the exact same way that it can into frame.

This is our mostly likely hypothesis because the observed data supports it. So through a matter of deduction, we have eliminated the dust particle hypothesis due to it's relative determination. The reflected light hypothesis is negated as well as the observational data is too inconsistent.

However, this would be a claim of weak underdetermination. The only way to definitively prove the hypothesis would be to replicate it.

Example 2, The Ghost at the Santa Fe courthouse

Our next example is a video captured by a security camera on the old Santa Fe courthouse. The story was reported by the local news with a group of "ghost hunters" saying that "they have seen things like this before", implying that the object in the video is paranormal.

The camera is located on the south side of the building about 20 feet above the ground and is enclosed in a weather proof casing. The railing leads to a door and the south side of the building is just out of frame to the right of the video but the sidewalk is visible.

The camera is shooting less than 30 frames per second.

The "phenomena" was noticed by security personnel working at the courthouse and having no logical explanation, it became a news story.

As with our previous example, we will start by breaking the video apart and making observations. We will then form several hypotheses and allow the data to guide us to the most probable answer.

As mentioned previously, it is important to establish if the object in the video is in the near field or the far field, so we will pay particular attention to elements that may help distinguish between the two.

Observation 1: Part of the video image is overexposed due to sunlight. This, combined with lens flare, determines that direct sunlight is reaching the camera lens. (Image 1). If something was on the protective glass of the camera, it would be out of focus and overexposed.

Observation 2: As the object enters frame, it obscures the railing on the far right of the video (Image 1). this is indicating that the object is in the foreground (near field).

Image 1

Observation 3: As the object moves across the video frame, it seems to cast a shadow. This observation requires a little critical thinking. If the object was something closer to ground level and was emitting light, it shouldn't leave a shadow. In fact, it should do just the opposite. The reflection of it's emitted light should be clearly visible in the police car's windshield and body (Image 2) and should also have an effect on the natural shadows in the video when it moves through them (Image 3). The object in the video does neither.

Observation 4: The object does not show any significant change in size as it moves across the field of view (typical of near field phenomena).

Observation 5: The object exits frame in the same fashion that it entered frame (also typical of near field phenomena).

Image 2

Image 3

All of our observations clearly indicate that the object is a near field phenomena, which would eliminate any possibility of a ghost taking a stroll through the courthouse parking lot. So exactly what is it?

I eliminated my hypotheses down to two possibilities;

1. A drifting cottonwood seed (they are common at the time of year when the video was recorded)

2. A bug or spider crawling on the outer shield of the camera's weatherproof enclosure.

All of our observations are consistent with both hypotheses, therefore the result would be a claim of weak underdetermination (the available evidence does not completely contradict either hypothesis)

However, the scientific method has a way to determine which hypothesis would be the most accurate. This is done through the replication of each hypothesis. This is the only way to rule out the variables that separate the two hypotheses from each other.

The video on the right shows the cottonwood seed hypothesis being tested. After the results of the test failed to match the recorded phenomena, the bug hypothesis was tested and the phenomena was successfully replicated.

It should be noted that in both examples, the use of critical thinking and scientific method enabled us to narrow down the variables of what the phenomena could be by simply using the data that we gained from observation of the videos. The hypothesis were not biased by adding unknown variables through assumption or undermined causes.

Why is this so important?

What difference does it make if the object in our first example is a particle of dust or a flying insect? Neither of them are paranormal, so why go through all of the hassle to determine "exactly" what it is? There are three important reasons why.

1. The quality of a paranormal investigator is determined by the ability to identify normal phenomena and then to differentiate the normal from possible paranormal phenomena.

There are no credentials for the investigation of paranormal and unknown phenomena. However, credentials do exist for the study of known phenomena and it is the ability to distinguish between the two that separates the ghost hunting hobbyist from the serious researcher.

By misidentifying a phenomena, you open yourself up to the worse criticism that can be given. All a skeptic has to do is to examine the data and prove that your "explanation" for the phenomena is incorrect. This would be demonstrated and followed up with a comment like;

"It is obvious that these people cannot even properly identify known phenomena. So how could one possibly trust their opinions on "paranormal" phenomena. They do not know what they are doing and all of their interpretations are misguided or outright false. It is nothing but pure fallacy."

This is a poignant argument because it deals directly with the groups methodology, knowledge and their analytical capabilities. Do they really know what they are doing? So the difference between a insect and a speck of dust is more important than it may initially seem.

2. This is also a double edged sword. Knowledgeable researchers can use the same techniques against their skeptics to show their inability to evaluate data (or at least force them to provide a more accurate analysis of your observations).

3. This is how new knowledge is gained. If the observations do not fit the concept of your proposed hypotheses, it may suggest the formation of a new hypothesis. the search for knowledge to provide an answer may lead to new knowledge and possibly, other hypotheses.

Cody Polston is the Founder and President of the Southwest Ghost Hunter's Association. Formerly an Explosive Ordnance Disposal technician, he has a varied scientific background related to that particular field. With over twenty years of ghost research, he initially started out as a skeptic before forming SGHA.

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