Introduction
Critical thinking is widely regarded as one of the main aims of education, and a tool that is necessary today for us to try to navigate safely through the oceans of misinformation that abound on the internet. A critical thinker, ideally, is a good estimator of the reasonableness of claims, arguments, and courses of action, a person who is able to calibrate the strength of their beliefs according to the quality of the evidence and reasons available to them. Or, in the words of philosopher Harvey Siegel,Footnote 1 a critical thinker is someone who is ‘appropriately moved by reasons’, a person who is able to evaluate properly the force and adequacy of reasons, and has a permanent inclination to assess reasons related to the broadest range of (important) topics, and a disposition to believe accordingly.
In spite of the widespread appraisal of the relevance of critical thinking for all of us, its exercise is somehow difficult. Contemporary research in cognitive and social psychology has suggested that to think critically is not our ‘default’ condition. We tend to avoid heavy cognitive loads, and this is one reason why we often resort to fast thinking processes, especially in situations that seem familiar to us. We are also subject to a myriad of conscious and unconscious cognitive biases that may be defined as ‘common intuitive reasoning strategies which can sometimes lead to illogical and unwarranted inferences and judgments’.Footnote 2 These reasoning strategies may cloud our capacity of judgment, and one of the most famous and studied of them is confirmation bias, ‘the tendency to seek and focus on information and evidence that will confirm our views and to fail to seek information which might counter those views’.Footnote 3
At schools and universities, one of the greatest difficulties educators face in fostering critical thinking among their students is the influence of previous beliefs. That does not mean that the previous beliefs of someone on a certain issue are necessarily wrong, bad, or inadequate. It means that some elements of our world-view are so strongly kept that we find it hard to apply critical thinking to claims related to them. In this case, confirmation bias is frequently working: if you believe A, then you will actively search for reasons and evidence that sustain A (or claims closely related to A), and discard arguments and points of view that might show you have been wrong on the subject. As Simon and Garfunkel sing in their hit ‘The Boxer’: ‘All lies and jest | Still, a man hears what he wants to hear | And disregards the rest.’
Our beliefs normally do not stand by themselves, that is, they find support (or are rejected) in accordance with other beliefs we hold, in a kind of ‘web of beliefs’. Some beliefs are more basic, which means we take them for granted when we are deliberating about an issue. If you assume there is a God (a basic belief), then you might also embrace the idea that He or She can be contacted through praying, and is capable of performing miracles. But again, basic beliefs tend to be reinforced by several biases, and they tend to influence the way we evaluate new information.
Ponder the following claim: certain individuals, the so-called psychics, are able to contact the spirits of dead people. How reasonable do you think this proposition is? If you do not believe in the afterlife, you will probably say that it is unlikely, or even utter nonsense. But what if you ‘firmly believe in a Supreme Being and that there is a Hereafter’,Footnote 4 and are emotionally in need to contact your deceased mother? Then you would probably be inclined to regard the allegation of (at least some) mediums as real.
It was Harry Houdini, the great magician and escape artist, who wrote the sentence quoted above. Houdini developed a great interest in the possibility of contacting the souls of dead people, and he became more intimate with the famous psychics and the séances of his time (at the end of the nineteenth century and in the first two decades of the twentieth) after his mother Cecilia died in 1913. The urge Houdini felt in trying to contact his mother can be better understood in the preface of A Magician among the Spirits, a book he published in 1924: ‘I believe in a Hereafter and no greater blessing could be bestowed upon me than the opportunity, once again, to speak to my sainted Mother who awaits for me with open arms to press me to her heart in welcome, just as she did when I entered this mundane sphere.’
Considering the great confidence Houdini expressed in his basic beliefs about a divinity and the afterlife, and his desire to accept the reality of the communication with the dead, one might have predicted that Houdini would have been strongly disposed to endorse the performances of the Spiritualist mediums he had met as real instances of contact with spirits. But Houdini was a skilled magician, and he knew how individuals could be fooled by tricks that, although common for illusionists, could have a tremendous impact on lay people. So, he decided to investigate whether the performances of some of the most famous mediums of his time were real instances of contact with the souls of the deceased, and the results are presented in A Magician among the Spirits, a book that may be read as an insightful exercise in critical thinking.
Houdini as a Critical Thinker
Critical thinking, according to the definition presented by Siegel, has two core elements: (a) the reason assessment component, which is related to the ability someone has to evaluate reasons and evidence properly; and (b) the critical spirit, which is, in short, an inclination constantly to seek and evaluate reasons and evidence, and base beliefs and actions accordingly. While the reason assessment component is essential for the proper evaluation of evidence regarding a certain claim, the critical spirit is a behavioural disposition to do so. Houdini, in his quest to investigate the reasonableness of the claims made by Spiritualist psychics, incorporated both to a great extent.
At the end of the nineteenth and beginning of the twentieth centuries, Spiritualist mediums claimed they could connect to the spirits of dead people, and there appeared to be some evidence indicating that the powers of psychics and their séances might be real instances of interaction between this world and the hereafter. People pointed out that mediums were able to present information about the deceased that could not be known unless it was told to the medium by the spirit of the dead person himself; weird things usually happened during the séances: objects moved around the room, sounds were produced, and their sources could not be tracked by anyone present. The evidence was endorsed by committees composed by intellectuals of the time, some of them scientists, who had participated in séances and could attest that the things that happened during the sessions were not produced by the living or faked by the medium.
How can someone evaluate those claims? Or, more specifically, how is it possible to evaluate the evidence that is offered to justify the claim that the spirits of dead people could be contacted by mediums? That is basically the task of a critical thinker: to assess the set of evidence, and then conclude if it constitutes adequate reason to justify belief in the capacity of psychics to communicate with the dead. Houdini thought that the most reasonable way to test the claims of the mediums was to observe and try to replicate the performances in which the effects of the presumed spirit manifestations could be perceived, and he did it himself and with the help of some of his fellow magicians.
The evidence presented by the mediums and their followers, however, was insufficient to convince Houdini. The magician attended some sessions himself, and he was aware that he and other illusionists were able to replicate most of the features of the performances he watched.
I am willing to be convinced, my mind is open, but the proof must be such as to leave no vestige of doubt that what is claimed to be done is accomplished only through or by supernatural power. So far I have never on any occasion, in all the séances I have attended, seen anything which would lead me to credit a mediumistic performance with supernatural aid, nor have I ever seen anything which has convinced me that it is possible to communicate with those who have passed out of this life.Footnote 5
Some of the elements of the séances were not simple to explain, as Houdini recognized. In certain occasions, the medium possessed personal information about a deceased individual so accurate that it was hard to think it was simply a product of ‘fishing’ about details of his life from friends or relatives. However, as Houdini discovered, certain psychics had much more sophisticated procedures:
During one of my engagements in Berlin, Germany, I made the acquaintance of the foreman of a safe factory who told me that he made a duplicate key for every safe which passed through his hands and that he sold these keys to mediums but with the express understanding that there should be nothing stolen. The mediums assured him that all they wanted was an opportunity to read the mail and private papers which the safes contained.Footnote 6
Houdini did not claim he could explain every aspect of the performances he had watched – or of the sessions attended by his fellow magicians – because many details were well hidden by the mediums (such as the association with a safe maker), or even because some of the features that happened were completely due to chance or coincidence. As an example of that, Houdini recounted a rainy day on which he was approached by a child who asked the magician if he could stop the rain, to which Houdini replied affirmatively. The illusionist raised his hands and the rain ceased to fall right after he ordered it to stop; some minutes later, under a new command by Houdini, the rain poured again. So, having had a reasonable appreciation of what happened during the séances, Houdini asserted that the performances of the psychics were entirely explainable without having recourse to supernatural phenomena.
To conclude that the phenomena presented by the mediums were explainable in natural terms, Houdini used what is known as ‘inference to the best explanation’, a process of reasoning in which someone decides which explanation is better able to account for the observed evidence, using criteria such as simplicity, coherence, testability and predictive power, and comprehensiveness in scope.Footnote 7 Suppose a group of people who are attending a séance see a table levitating some centimetres from the floor in a dark room. Given two explanations for this phenomenon, which seems more reasonable: (a) a medium has contacted the spirit of a dead person, and the manifestation of the spirit somehow makes the table to move; (b) a medium (or someone else in the room) is able to make the table ‘levitate’ with a subtle move of his or her feet, or using a different strategy (pulling a string in a lever, etc.)? Houdini considered – correctly – that scenario (b) was the most likely to explain what people witnessed in some Spiritualist sessions, given that he knew in advance that other magicians had performed similar tricks without claiming they were supernatural, and so this explanation was the simplest and the most coherent with the established fact that objects can be moved by physical processes without people around being aware of how this is done.
Inferring to the best explanation, Houdini was also justified in believing that what was said in a séance about a dead person was not due to the capacity the medium had to contact a spirit, but rather the ability of the spiritualist to gather data about the deceased beforehand. This reasoning also applied to the strange sounds heard in some sessions (it was possible to produce them without being noticed), to the messages that suddenly appeared on slates that were blank (short messages could be written by the mediums who had a small pencil hidden in their hands; longer messages were previously written in slates that were switched by the psychic and his or her assistants), and so on. So, it was not necessary to postulate the activity of spirits as the explanation for the features exhibited by Spiritualist mediums.
According to Houdini, the performance of mediums should be accessed by multidisciplinary committees, but one professional was permanently required in them: a magician. Some scientists had attended Spiritualists’ sessions and became impressed with what they experienced, but Houdini was aware that it was due to their lack of familiarity with magic tricks. Scientists and laymen were equally potential victims of the ability of deception, but magicians were much more difficult to fool. This is a lesson that is still valid, and the figure of James Randi is the greatest example of a contemporary illusionist who has invested his time and talent in exposing and debunking charlatans who pretend to have supernatural powers.
The Critical Spirit of Houdini: a Commitment to Serious Investigation, not Uncritical Belief
When we compare the attitudes of Houdini with those of his famous friend Sir Arthur Conan Doyle towards the claims of the Spiritualist mediums, we can appreciate how the former had developed what Harvey Siegel calls ‘the critical spirit’, a core element of critical thinking. Houdini desired to believe psychics could contact the spirits of the departed but, more than that, he wanted to know if this was true, and because of that he was permanently committed to investigate the allegations of several famous mediums, a posture that was different from Doyle's, whose faith, according to Houdini, had misguided him on several occasions.
Doyle had a very strong belief in Spiritualism and in the claims of the mediums, and the strength of his beliefs did not seem to be diminished in any circumstance. Houdini had warned Doyle regarding the tricks that could be performed by psychics during séances, and even told the creator of Sherlock Holmes about several cases in which the mediums were caught cheating during their performances. But, contrary to what happened to Houdini, these facts had little or no apparent effect on the opinion of Doyle about the pretended supernatural powers of certain Spiritualists.
On one occasion, Doyle and his wife invited Houdini to a séance that would be conducted by the couple at their house. The objective was to contact Cecilia, the mother of Houdini, and the magician was as open as he could be for embracing convincing evidence of the manifestation of the spirit of his dear mother:
Sir Arthur started the séance with a devout prayer. I had made up my mind that I would be as religious as it was within my power to be and not at any time did I scoff at the ceremony. I excluded all earthly thoughts and gave my whole soul to the séance.
I was willing to believe, even wanted to believe. It was weird to me and with a beating heart I waited, hoping that I might feel once more the presence of my beloved Mother. If there ever was a son who idolized and worshipped his Mother, whose every thought was for her happiness and comfort, that son was myself. My Mother meant my life, her happiness was synonymous with my peace of mind. For that reason, if no other, I wanted to give my very deepest attention to what was going on. It meant to me an easing of all pain that I had in my heart. I specially wanted to speak to my Mother, because that day, June 17, 1922, was her birthday. I was determined to embrace Spiritualism if there was any evidence strong enough to down the doubts that have crowded my brain for the past thirty years.Footnote 8
Houdini, however, left the séance convinced that the performance of the Doyles had been a failure. A letter written in English, purportedly dictated by Cecilia, was given to Houdini, who refused to accept it as a piece of evidence for the presence of his departed mother, given that she did not know how to speak, read, or write English. To that objection Doyle replied that ‘a spirit becomes more educated the longer it is departed’,Footnote 9 and that the mother of Houdini had mastered the English language in Heaven, but both assertions did not impress the illusionist.
Arthur Conan Doyle was regarded as a bright person – ‘a brilliant man, a deep thinker, well versed in every respect’, in the words of Houdini.Footnote 10 Nonetheless, ‘Sir Arthur believes. In this great mind there is no doubt.’Footnote 11 And the fact that Doyle was sure Spiritualism was true may have fostered his confirmation bias and other cognitive mechanisms to protect his cherished beliefs, and undermined his critical spirit, which could have helped him to deliberate about the reasonableness of many of the Spiritualists’ claims.
We have a tremendous difficulty in applying our critical thinking skills to all relevant areas, issues or problems that would be better approached with deliberation. In particular, we fail to apply critical thinking to many topics to which we are emotionally attached, and this is one of the reasons why we hardly change our minds about beliefs that we hold in high regard. That means all of us lack the critical spirit to some extent – and that may be one reason why critical thinking is difficult to teach: people can learn skills to evaluate arguments, but the disposition to use these skills as broadly as possible, that is, the critical spirit, is hampered by many of our natural cognitive traits. It demands a lot of effort and exercise to be impregnated by the critical spirit the way Houdini was when he investigated the Spiritualist mediums.
Was Houdini the Quintessential Critical Thinker?
While investigating the claims of Spiritualist psychics, Houdini applied cognitive tools and behavioural dispositions that are today regarded as fundamental for the exercise of critical thinking. Houdini was not afraid to put to the test some of the propositions he desired to be true, and honestly evaluated their merits. He was aware of how his prior beliefs could lead him astray, so he tried hard to manage his (conscious) biases and preconceptions. Houdini understood the difference between desiring something to be true, and having good reasons to regard something as true. And he also developed a clear insight about the concept of ‘burden of proof’, an idea that is frequently invoked in contemporary debates about pseudoscientific and/or supernatural claims:
It is not for us to prove that the mediums are dishonest, it is for them to prove that they are honest. They have made a statement, the most serious statement in recent times, for it affects the welfare, the mental attitude and means a complete revolution of age-old beliefs and customs of the world. If there is anything to Spiritualism then the world should know it. If there is nothing to it, if it is, as it appears, built on a flimsy framework of misdirection, then too the universe must be told. There is too much at stake for a flighty passing, for unsubstantiated truths.Footnote 12
Houdini, however, seemed unable to question some of his sacred basic beliefs, namely that there is God and that there is another life after this one – at least in A Magician among the Spirits he does not raise a doubt about the veracity of these two assumptions. Perhaps here Houdini struggled with the same difficulties that Sir Arthur Conan Doyle had with the claims of the Spiritualists – he was very good at thinking critically about A, but did not extend his cognitive abilities completely to B.
We should regard critical thinking as a group of cognitive abilities and behavioural dispositions that come in degrees. Someone may be a better critical thinker in certain contexts, and a worse critical thinker in others. Think about the brilliance of the creator of Sherlock Holmes in creating very thoughtful stories, and then remember Doyle easily fooled by the psychics: it is difficult for someone to be a perfect critical thinker under all circumstances.
A Magician among the Spirits is the account of a tremendous critical thinker in action. But perhaps there is no such thing as a ‘quintessential critical thinker’, because critical thinkers are humans, and humans are imperfect reasoners – although we are able to do an excellent job, as did Houdini in his journey in search of the spirits.
