Seven fallacies of thought and reason

A look at the most common logical fallacies and how they are used.

by Jason Braithwaite PhD © 2006

There are many forms of logical fallacy, errors, and mistakes of reason. In addition to this many fallacies co-exist and network together in yet further complex combinations. The net consequence of this is a conviction and feeling of coherence in the views being held - a sense of things making sense! This feeling of 'everything making sense' in the absence of any evidence, logic or reason, is an illusion based in the collective impact of unstructured thought.

The level of the delusion is often far greater than the sum of its underlying parts. The mistakes of thought and reason listed here have been chosen and highlighted on the basis that they are the most common. Therefore, these errors are so prevalent, they have permeated and perverted the public's perception of science the most.

The seven main fallacies are listed here in reverse order. The order generally relates to the popularity and persuasiveness of that fallacy in general popular science and pseudoscience, with number 7 being the lesser and number 1 being the most popular forms of fallacious thinking and argument. The combined outcome of accepting these fallacies is the same - they all lead to error in thinking. All represent mind-traps in thinking that lead ultimately to either unsound thinking or a completely fictitious characterisation of science and the processes of legitimate scientific argumentation.

(7) I am entitled to my opinion (used to support the truth of the opinion).

A quite common outcome in arguments between science and pseudoscience is when the person holding the failing position resorts to saying "…well, that is my view and I am entitled to my opinion." This is often recruited in support of the argument being made, thus implying that ones entitlement is somehow important for the truth of the argument itself. Indeed they are entitled to their opinion, but their entitlements were never in question. We are all entitled to our opinions - but this has no consequence for the scientific truth of them and does not establish or justify the validity of them. So the problem here arises when one recruits the mere 'entitlement' (and no evidence) to a view, as some form of evidential support for the truth of the view. It is often used as a final defence mechanism when faced with quite strong counter-arguments and evidence.

The crucial point with this error in argumentation is that your individual entitlement to hold a view is no indication at all as to its validity or truth - indeed, it is completely irrelevant (a form of the non-sequitur fallacy). When having a scientific debate, discussing evidence and theory, it makes no sense to recruit your human rights and 'entitlements' in defence of any view. It shifts the focus from one of science, evidence, and reason to one of human rights (see Whyte, 2005). This is an irrelevant and unhelpful tangent. You are of course entitled to hold any view you please, but it becomes a fallacy of reason to recruit that mere entitlement as some form of evidence in support of the truth of that view.

Recruiting the 'I'm entitled to my opinion' stance in any debate is functionally equivalent to saying, 'I am entitled to be wrong!' Entitlements do not establish truth. Human entitlements and rights are irrelevant to a scientific debate based on facts, evidence and reason. A scientist may be entitled to his / her opinion of the facts, but their entitlements do not make them correct, their data and evidence makes them correct. A scientist is entitled to believe that the boiling point of water is 100 degrees Celsius, but the entitlement to that view does not make the scientist correct - the facts gained from scientific study provide evidence - which actually exists independent of anyone's view of it. Therefore, it is sound reasoning, logic, and the recruitment of supportive empirical evidence of quality that makes an argument more likely to be correct.

(6) Argumentum Ad-hominem: Shoot the messenger fallacy

This is a common logical fallacy. Argumentum ad hominem basically means that the argument becomes directed towards the individual as opposed towards the crucial issues being discussed. It is succinctly described as, attack the messenger not the message (hence - shoot the messenger). It is often seen in both politics and pseudoscience. Its aim is to undermine the position of ones opponent, by undermining the opponent personally (in a manner that is actually completely irrelevant to the debate). The hope here is that if one can discredit the individual, this by default, discredits his / her argument. It does not. The fallacy here relates to the irrelevance of the attack. It is not viable to argue against a position and then justify that argument by criticising the individual who holds it. Arguing that the proposals from the Educational minister are unlikely to work because he / she have no children of their own is hardly convincing. Furthermore, saying that Einstein or Darwin were selfish men does nothing to discredit the theories of Relativity and Evolution. They may have been the most selfish or the most unselfish of men, but this is an irrelevance as to the 'truth' of their scientific claims. Similarly, a cognitive neuroscientific account of strange experiences (i.e., near-death experiences) is not incorrect simply because the scientist proposing it is a skeptic. These are all examples of the ad-hominem fallacy. Any claim or theory should not be rejected solely on the basis of who holds it.

(5) I'm offended! (A special case of the red-herring fallacy)

When a core belief is under threat from a good counter-argument it is common for many to defend the belief by stating "I'm offended". Here the person whose beliefs are under threat seeks to defend their position and thinking, not with evidence and argument, but by throwing out an often unjustified comment claiming to be offended. Creationists get offended by Evolutionary theory, Parapsychologists get offended by more sceptical scientific interpretations, and Pseudoscientists get offended when their unfounded premises and illogical cherished ideas are called into question. None of this of course, means that the beliefs of the individual being offended are actually true. It means nothing and can be cast as an instance of:

  1. the red-herring fallacy (evading the issue via diversion);
  2. to some degree the non-sequitur fallacy (where the argument does not follow from the premise, or the conclusion does not follow from the argument), and/or;
  3. the irrelevant objection fallacy (where the completely irrelevant tangent of being offended is recruited as an objection to the argument).

The problem is the 'I'm offended' card gets played far too easily for those whose position is difficult to defend. It is often recruited even when an opponent in a debate makes a perfectly reasonable suggestion or asks a respectful but challenging question.

Playing the 'I'm offended' card every time the debate gets interesting is neither a well reasoned, sensible or scientific position to take. It has no place in an adult intelligent debate about the issues. The perception comes about because to question a core belief of someone is, to them, to question them personally. It is not and nothing could be further from the truth. This 'red herring' fallacy is an attempt to steer attention away from the real crux of the issue that many find difficult to deal with. It liberates such individuals from having to justify and support their argument. If you say 'I am offended' then that's all you need to say and in the minds of such people it gets them out of having to consider the issues at hand. It is a sort of cognitive defence mechanism - that serves to protect the belief position of the person. It seems their position really is - "I get offended by anything you do not agree with" - how can this be a viable position for a reasoned argument on science?

(4) Science cannot explain everything and does not have all the answers.

This argument goes something like - as science cannot explain everything and does not have all the answers, it follows that:

  1. science is limited; and
  2. other answers from other knowledge systems could be true (i.e., belief-systems and pseudoscience).

Or to put it another way, science is limited and those very limitations stop it from answering specific questions concerning certain issues. This is then typically used to gain leverage for claiming a 'truth' via these other knowledge systems (typically ones that don't employ the principles of science). Common examples would be debates on psychic abilities, the existence of an after-life and the existence of apparitions from areas like parapsychology and popular science.

There are a number of reasons for why this argument is a falsehood. Firstly, science never claims to have all the answers - just a reliable and useful method for revealing them. So attacking science for not having all the answers is something of a straw-man argument in the first place (blaming science for not being able to do something - it never claimed to be able to do in the first place!). Secondly, the argument is based in the assumption that the limitations of science actually have any implications for what is being proposed. Although science is indeed limited, it does not automatically follow that these limitations have any implications for the existence of certain phenomena (i.e., of paranormal phenomena). The problem here relates to the idea that the limitations of science have any bearing whatsoever on the failure to find any evidence for, say, paranormal phenomena. However, if Extra-Sensory Perception (ESP) exists, a relatively simple science of mathematical probabilities, chance expectancies and well controlled experiments would be able to demonstrate its existence. The same would hold for other claimed abilities (mind reading, psycho-kinesis, mediumship, dowsing, remote viewing, etc). Science has had techniques and methodologies at its disposal for many years that are more than suitable to test and refute (or establish) such claims.

A relatively basic and simple well-controlled science would be more than sufficient to establish the truth of these claims. Thirdly, the limitations of one knowledge system do not, by default, add credence or support to any alternative. That is, although science may well be limited, this does not mean that alternative knowledge systems have any additional merits by default. For instance, gaps in knowledge from Astronomical science do not mean we should abandon it for Astrology. For Astrology to be a viable alternative it would need to demonstrate its own credentials for knowledge and understanding, independently of the limitations of any other system. The fact that science does not have all the answers, does not mean that pseudoscience has any answers at all (or is indeed capable of ever producing any)! This is the crucial delusion underlying this argument. On this basis, the argument is meaningless.

(3) Science is often wrong, and has been shown to be wrong before, therefore it could be wrong about the paranormal.

A common argument against science is that, it has been wrong before - so it could be wrong again and also about issues that pseudoscience promotes. Despite popular opinion, science is not about absolutes and definite proof. Science deals with the most plausible, probable and likely explanations based on the evidence available at any given time (i.e., it is probabilistic). As noted earlier, science makes the explicit commitment that any scientific truth is provisional and although any account may turn out to be false in the future, it may be the best account in the present. The underlying thought processes at work in pseudoscience play on the notion of science being about probable truth (as opposed absolute truth) as a weakness. Once the idea of a weakness in science is proposed, it is a small step to further claim the lack of absolutes implies that no theory can be considered completely 'true' and thus, could be totally wrong. Furthermore, as scientific ideas are not 100% true; then pseudo-logic states that:

  1. any idea could be a viable alternative to the scientific theory; and
  2. all existing ideas are equally valid and equally true. Herein lay the fallacies of this argument.

In reality the explicit commitment of science being about provisional truth is actually a strength. It is an open commitment to knowledge never being infallible. There are many complex areas of inquiry and finding answers is not easy. Initial ideas and hypotheses may be quite wrong; however, where they are shown to be wrong, they will be amended and retested. Via this process, we get closer to what is true every step of the way by being less wrong than before. To argue that science cannot prove things to be 100% true is fine, but for people to use it as an argument to give validity to completely untenable ideas is fallacious. Pseudoscientific ideas can be quite wrong for reasons that have nothing to do with the limitations of science. Both pseudoscience and science may be wrong; but science is highly likely to be far less wrong than pseudoscience.

Let us examine the initial notion of science having been wrong before (as this is the basis underlying this argument). Science has indeed been wrong before. Science is not 100% foolproof and it has never claimed to be perfect. Sometimes ideas need refinement and sometimes ideas require a complete refutation. However, this is not a weakness or a fault of science. Indeed, it is a fundamental and accepted part of the process of science as it discovers provisional truths. As science explicitly acknowledges that all knowledge is provisional, this makes it clear that current knowledge can be, and indeed should be, constantly revised if it is necessary to do so. Crucially however, the errors in science are not revealed to the educated world by pseudoscience! Science identifies the errors in scientific knowledge in the first place. This highlights an important aspect of science - that is, it is self-policing. Fraud, error and mistake, if they occur, will be discovered. The process of science identifies and corrects its own mistakes.

Pseudoscience also makes a fundamental contradiction here in relation to its argument. Pseudoscience criticises science for prior mistakes - but uses the new knowledge produced by science to attack earlier scientific ideas. From this position it attacks science itself. This is odd when one realises that the new knowledge which pseudoscience tries to employ in its argument was not produced by pseudoscience, but was actually produced by the very system pseudoscience seeks to attack and undermine! That is, it uses new science to attack old science and then attack the whole process of science itself. Pseudoscience also fails to understand that older ideas, which may have been incomplete, aid newer and more comprehensive ideas. There can be far less friction between new ideas and older ones than pseudoscience would have you believe.

A further failing in this argument against science is that although science may well have been wrong before, this does not mean that pseudoscience has ever been correct ever! That is to say, the limitations of science do not, by default, provide support for any form of pseudoscience. To be a viable source of knowledge and understanding, pseudoscience requires its own merits.

(2) Science cannot disprove the paranormal - therefore, this failure is, by default, support for the existence of paranormal phenomena.

This is a fundamental misunderstanding of a number of central principles of science. It reflects a variety of logical fallacies and mistakes of reason. These include:

  1. argumentum ad ignorantiam;
  2. a misunderstanding of the difference between the evidence of absence and the absence of evidence;
  3. a misunderstanding of the principles of falsifiability and sufficiency;
  4. a shifting of the burden of proof.

These, along with other contextual issues are discussed below.

Argumentum ad ignorantiam basically means the argument to ignorance. The underlying fallacy from the argument to ignorance is when it is argued that something must be true, purely and simply because it has not been proved to be false (or vice versa). Carroll (2004) suggests, this fallacy could also be called the "fallacy from lack of sufficient evidence to the contrary" (Carroll, 2004; pp115). The fallacy of the argument to ignorance is not based in any one individual in an argument being ignorant - it is thus not directed to the individual. The notion of ignorance relates to the form of the argument itself. In this case, to there being 'no evidence' and thus, we are ignorant of the potential truth. The crucial point to keep in mind here is that an inability to disprove a claim does not automatically mean that the claim being made is true. An individual might make the claim that he / she can run the 100 metres sprint in under seven seconds (which would be the fastest ever recorded). However, if the person refuses to be tested in a race, our inability to falsify the claim does not make the claim true by default. If this was the case, anybody making a claim like this would be eligible for an Olympic gold medal, without ever having to run a single race!

A similar fallacious argument to ignorance would be one that states "as nobody can prove God did not create the universe, it must therefore be true". The lack of evidence means nothing either way. The fallacy also works in the other direction as well. For example, a statement like; "Of course apparitions do not exist, nobody has provided any proof that they are indeed real" is also an error in reasoning committing the same fallacy. In science, we can make the valid assumption that from the lack of evidence, something has not occurred. However, we cannot conclude with absolute certainty that it has not occurred.

One mistake related to the argument to ignorance is to falsely interpret the absence of evidence as being equal to that of there being evidence of absence. Clearly they are not equal. The crucial point is that although science may not be able to disprove a claim, this is not evidence in support of the claim. Science accepts claims, not just on the basis of the absence of evidence but mainly on the presence of confirming evidence (i.e., positive evidence). There must be positive empirical evidence for accepting any claim or argument as being true. The lack of any evidence itself is not direct support of an alternative paranormal theory. It is completely neutral on the matter. The absence of evidence for Creationism does not, on its own, provide support for the theory of Evolution. The theory of Evolution requires its own positive evidence to establish it as a truth. The confusion over the absence of evidence being the same as evidence of absence is also related to some misunderstandings over the notion of falsification in science.

The principal of falsifiability states that in order for any claim to be held as a scientific truth - it must be falsifiable. That is to say, we must be able to test it and falsify it. The rule of falsifiability is an assurance that if the claim being made is indeed false, then the evidence will show it is false; and if the claim is true, then the evidence will not disprove it. In the latter case we can accept the claim as a provisional account of 'truth' until such time as further evidence is produced which disproves it (thus, it is a provisional truth). Therefore, the rule of falsifiability makes the explicit commitment that the evidence must matter and has to matter in a well reasoned scientific argument. If we cannot test the claim being made then that claim is no more true, than it is false. The problem with pseudoscience is that many of their claims are not testable - yet this absence of evidence is often taken as direct support for the claim. As noted above, if the absence of disconfirming evidence were to be taken as proof for a claim, then it is conceivable that we could show anything to be true - even when it is totally false. In addition to this, Lett (1990) notes, this type of faulty reasoning is also related to the concept of 'sufficiency'. That is to say, any evidence recruited in support of a claim must be sufficient to establish the truth of that claim, in the manner in which it was made. The absence of disconfirming evidence for a particular claim, is not sufficient on its own to establish the truth of that claim. This type of reasoning is also relevant to a related error, that of it being up to science to disprove the existence of the paranormal. The discussion above shows clearly why this type of reasoning is incorrect and not a viable criticism of science at all.

Finally, another error in reasoning underlying these types of arguments relates to the burden of proof. It is not the job of science to disprove such claims (any claims). Indeed, science maintains that this is logically impossible. The burden of proof always rests with those making the claims. In other words the claimant must furnish the claim with good quality evidence, reason and logic. If a scientist argues that all species evolve through a process of natural selection, then he / she needs to support that claim with positive evidence for that process. If a parapsychologist argues that the mind is separate from the brain and can survive bodily death, then he / she also needs to support that claim with positive evidence. It is unsound to argue that the absence of evidence alone, due to:

  1. a failure of science disproving claims; and
  2. shifting the burden of proof onto others, somehow supports the claim being made.

The burden of providing positive evidence lies with those making the claims.

(1) Scientists and skeptics are closed-minded and are not open to other possibilities (not open-minded).

This is by far, the most perverse, corrosive, and commonly touted criticism that the ill-informed direct towards mainstream science. The underlying idea is that scientists are too strict and constrained in their thinking. By this account, science is seen as rigid and unforgiving. The basic suggestion being made is that scientists themselves are supposed to be so 'closed-minded' that they will not 'open their minds' to other possibilities (the implication here is that these 'other possibilities' are actually 'paranormal possibilities'). As a viable argument against science it is an irrelevance and a folly. This claim can occur for a variety of reasons and reflects a number of diverse errors in thinking and reason. Before the fundamental fallacies of this type of argument against science are addressed it is important to consider just what being open-minded really means (as opposed to what pseudoscience would like it to mean).

In contrast to popular opinion, being open-minded does not mean considering all and every possibility as equally viable. This is impractical and besides, many ideas and claims are completely unsupported by the evidence or are also simply ridiculous. Should we view the idea that homeopathy can cure illnesses, as being evidentially equivalent to that of mainstream medicine? The claim that the earth is flat is not as valid and evidenced as the fact that it is round - so why should we view them as equal? Is the idea that aliens may have abducted someone in the night and then returned them as equally plausible as the idea that maybe they dreamt it? For all these instances, the current evidence suggests a clear answer - no! All ideas are not equally valid, ideas that are supported by reason, and more evidence of a higher quality are more probable and more relevant than those ideas that have neither. Once acknowledged we can see that one of the main claims of pseudoscience; that of all ideas being equally valid, is clearly ridiculous. The fundamental mistake of pseudoscience is to misrepresent and misunderstand what being open-minded really means.

Therefore, being open-minded certainly does not mean accepting all manner of claims and weird ideas equally. It is not the case that all ideas and claims have equal evidential weight. To accept claims uncritically, in the absence of supporting evidence, has nothing to do with being open-minded. Accepting claims purely on the basis of belief and wishful thinking is to be credulous. Open-mindedness is often confused for credulity; the two are not the same thing. The implicit theme running through this line of fallacious argument generates a kind of false argument in that if scientists and sceptics do not endorse and embrace pseudoscientific arguments as true, this is because they must be 'closed-minded' (as opposed to the more likely explanation of the argument simply being false).

What pseudoscience fails to acknowledge is that to be truly open-minded, the researcher must entertain and consider the possibility that an idea may be true, and entertain the possibility that an idea may be completely false. Therefore, open-mindedness means the researcher is open to both possibilities! There is nothing closed minded about openly and objectively considering an idea or claim and then rejecting it. Pseudoscience seems to see open-mindedness as the uncritical acceptance of unsupported claims and ideas; to accept that which they hope is true, as opposed to that which is more likely to be true. Pseudoscience basically states that any idea should be accepted with an 'open-mind' and thus, such acceptance indexes an open mind. Clearly it does not. Pseudoscience completely fails to entertain the possibility that science has considered their suggestions, claims and arguments and merely rejected them in a fair and reasoned manner. Pseudoscience does not realise that the views of science are actually based on a considered approach. Scientists have done nothing wrong other than to back the idea with the highest quality evidence, supporting the most reasoned and the most likely account.

The reality is that science deals with the most probable and most plausible arguments and claims. Such plausibility and probability emerges through the existence of empirical data, objective facts, evidence, logic and reason. This process does not result in closed-mindedness to other possibilities, but open-mindedness to all plausible probabilities. That is to say, it results in open-mindedness to the most likely and true explanations. Being an open-minded person means considering ideas and arguments on these criteria. If the argument or claim being made can be shown to be correct, then an open-minded person will modify their views accordingly - indeed science would demand this in the face of good quality evidence. If the argument is found wanting in a number of fundamental aspects, it will be soundly rejected and with good reason.

Another problem with the 'closed-minded' argument against science is that it is a form of generic ad-hominem fallacy. However, instead of being directed at one person, it attacks a whole system of thought as opposed to dealing with the testable and refutable knowledge and understanding it generates. This charge is usually made by those who cannot provide any high quality data for their pet-theories or do not like the high-quality evidence science has produced. The net consequence is to attack science itself as a system of knowledge. It is also often applied in and an ad-hoc manner, where the scientist is only categorised as being closed-minded when it becomes clear they do not concur or support the position of the pseudoscientist. It has nothing to do with whether the scientist has good reason to disagree, or has evidence of a higher quality that comes to a different conclusion - the 'close-minded' claim gets touted simply because the pet-theory of the pseudoscientist is soundly refuted. Attacking science in this manner is an irrelevance. It is also a debating technique to shift the arguments away from the fact pseudoscience has no objective evidence or sound underlying logic. In other words, it is an attempt to hide the fact that pseudoscience struggles to produce evidence. The closed-minded argument is also a form of straw-man argument. Like all the other fallacies listed in this paper, the closed-minded claim attacks an incorrect representation of science and what being open-minded really is. This makes it easier for the pseudoscience to attack science - but in reality what they are attacking, is not the reality of science, but their straw-man which is easier to knock down.

To summarise, the objective nature of science, the acknowledgement of all scientific knowledge being regarded as provisional, the explicit methods and need for independent replication, clearly show that the process of science is indeed open-minded. In contrast to the common perception, science is not about debunking ideas and rejecting claims out of hand; it is about investigating them in a serious, sensible, and reliable manner. The explicit acknowledgement to scientific knowledge being provisional is of course in complete contrast to a belief-system or pseudoscience. Under these latter circumstances any knowledge is final, fits with pre-existing belief, is biased, swayed by irrelevant emotions and wishful thinking, cannot be questioned, and must be accepted. These beliefs require only that the individual accept them in an unquestioned manner. However, for science all knowledge is open to be independently evaluated, tested, confirmed, revised or rejected. It is somewhat ironic that belief-systems and pseudoscience charge science with being "closed minded"! Clearly, by making an explicit commitment to all knowledge being provisional (as opposed to unquestionable), this is the most open-minded stance any knowledge system can take.


In recent years, pseudoscience has sought to undermine scientific knowledge by attacking science itself. This has led to a growing misperception amongst members of the public and some science students about what science is and how it does what it does. Many myths are propagated by popular science and pseudoscience with the explicit intention of undermining science. This paper has outlined what are perhaps some of the most popular and common arguments gaining currency in the public domain. These errors are united by both their fallacious form and the misrepresentation of the science they seek to attack. Science may not be perfect, but it is the best system we have. Pseudoscience has nothing to offer in terms of scientific truth and understanding. It seeks to delude and provide false hope. In contrast, science tackles how things are, not how we want them to be. This paper has highlighted potent errors in argument from pseudoscience with the aim of showing clearly why they simply do not work as viable challenges to science.