When debating life extension, or debating in general, it may happen that participants commit logical fallacies—that is, their arguments contain logically invalid reasoning. In practice, this often means that people incorrectly come to certain conclusions that do not actually follow from the premises; if they appear to follow, it’s indeed because fallacious reasoning was used.

Logical fallacies can be tough to spot, both for the people committing them and for the people listening; rejuvenation advocates would therefore benefit from familiarizing with common fallacies committed during debates about life extension so that they will both be able to detect them in other people’s arguments and avoid committing any themselves.

The following is a list of common logical fallacies that usually show up during life extension debates. It may be useful for your advocacy efforts, but bear in mind that the right way to go about rebutting fallacious reasoning is not simply pointing out “You committed a fallacy; your argument is invalid”; in fact, you’d better avoid mentioning the word “fallacy” altogether. What you are likely to get this way is simply a lot of eye-rolling; your message will probably not get across, and you will come across as an insufferable pedant, even if you’re right. I’ve personally met people who don’t seem to think that a logical fallacy in their reasoning is such a big deal. Debating with such people is probably a waste of time, but in general, people might be more receptive if you politely explain why their reasoning doesn’t work, providing different examples and avoiding a lecturing attitude at all costs.

Appeal to probability (or Appeal to possibility)

One commits this fallacy when concluding that something will necessarily happen on the grounds that it is or might be likely. In the context of life extension, this is often observed when people discuss potential negative outcomes of defeating aging—for example, someone could think that it is likely that therapies will be too expensive for most people for a long time and, therefore, implicitly conclude that this will necessarily be the case. This fails to take into account the things that could be done to prevent this unwanted outcome from happening, such as lobbying efforts for government subsidies or the fact that paying for people’s rejuvenation may prove more economically convenient for a government in the long run.

Such preventive or mitigative actions are sometimes incorrectly dismissed using similarly incorrect arguments, such as assuming that lobbying efforts are likely to fail and thus will necessarily fail; additionally, evaluation of these probabilities often relies on supposed truisms that appeal to people’s indignation to perceived injustice, i.e. “Politicians/Big Pharma would never allow this,” not on any real, supporting evidence.

The takeaway is that ‘likely’ doesn’t mean ‘certain’; additionally, likelihood must be established accurately, not through gut feelings.

Argument to moderation

This is the fallacy by which one infers that a middle ground between two opposing positions is necessarily always correct or the best option. An obvious example would be asserting that being healthy 50% of the time is superior to being always unhealthy or being healthy all the time. Another example would be saying that five financial losses are a good compromise between ten and no losses.

When discussing indefinite lifespans, an example would be that living only a finite amount of time is necessarily better than not living at all or living for an infinitely long time (on the currently debatable assumption that the latter is possible).

Whenever a judgement of value, such as “better”, is involved, the matter at hand is subjective and not objective; under exceptional circumstances, some people might have a reason to prefer being not fully healthy or taking a loss (though these circumstances are hard to imagine); for the very same reason, you can’t infer that a middle ground will always be better than either extreme for everyone.

Fallacy of composition

The fallacy of composition assumes that what is true for the whole must be true for a part of the whole. A good example of this would be concluding that nothing made of atoms (the whole) can be alive, because no atom (a part) is alive.

This fallacy is often committed in the context of life extension when generalizing to life what may be true of individual life experiences, typically in an attempt to prove that living for a very long time will be boring. Since people normally get tired of protracting a given activity for a very long time, then they would supposedly get tired of life if it goes on for a very long time. However, life is a collection of activities rather than a single activity, and many activities periodically regain their appeal. I might be tired of playing chess for today, but I may want to play another game tomorrow; I might be tired of having worked in a certain job for the last ten years, but I might want to do it again twenty years from now. It’s also unclear whether the number of different activities that someone may enjoy is finite or not.

Shifting the burden of proof

The burden of proof—the responsibility to back up a claim—is on whoever makes the claim. Shifting the burden of proof happens whenever you make a claim that needs backing up but demand that others prove it false instead.

In the context of life extension, this sometimes manifests when an opponent demands advocates to prove that a certain side effect, say, cultural stagnation, won’t happen. This side effect is typically one of the reasons why the opponent is against life extension in the first place.

However, if one objects rejuvenation on the grounds that it will cause cultural stagnation, it’s up to him or her to prove that cultural stagnation will actually happen. Asking advocates to prove that it won’t constitutes shifting the burden of proof; besides, as most future outcomes are impossible to predict with certainty, advocates may at best provide evidence suggesting a given side effect will not happen, or suggest ways to mitigate it, but they can’t prove it won’t happen.

If you happen to be faced with this fallacy in a debate about life extension, don’t simply tell your opponents that the burden of proof is on them. That is likely to just get them defensive. Rather, point out that the lives and well-being of 100,000 people are at stake every day; before we condemn them to suffering and death for the sake of avoiding a given side effect, we need to be extremely sure that this side effect is indeed inevitable, unmitigable, and worse than the suffering and death of countless individuals. This approach might prove more successful.

Argument from incredulity

This fallacy can be summarized as “I can’t imagine how this could be true, therefore it isn’t.” Obviously, whether something is true or not doesn’t depend on your ability to understand it; for example, nuclear fusion will keep making the Sun shine, even if you don’t understand how nuclear fusion works. This fallacy is also known as “Appeal to common sense”, because it leads to erroneous conclusions that indeed appear to be just “common sense”; for example, thousands of years ago, the idea that matter was made of air, fire, earth, and water was “common sense”, as these four things were commonly observed, whereas subatomic particles were not. Yet, the conclusion that the four elements make up everything was completely wrong, and it’s definitely not “common sense” anymore.

In the context of rejuvenation, this fallacy manifests as extreme skepticism concerning the feasibility of defeating aging. Most people don’t know the root causes of aging or that they’ve been proven to be malleable, and most people have grown up in a world where aging is commonplace and apparently inevitable. They cannot imagine how it would be possible to interfere with aging and have thus a hard time believing that it is feasible. To them, the inevitability of aging is just “common sense”.

Assuming that you’re dealing with reasonably educated and open-minded people, the best way to counter this fallacy is to provide a good explanation of what aging is and the progress that has been done in the laboratory.

Appeal to motive

The fallacy of appeal to motive consists in dismissing an idea on the grounds of the motives of its proponent. This is a form of ad hominem attack—attacking the proponent rather than the idea being proposed.

Any proponent’s motives may well be debatable, but the idea may still be good; for example, a billionaire might write a large check to UNICEF only for the sake of publicity without really caring about helping children. You may argue that his or her motives are questionable, but the donation will still benefit many children in need.

A typical life extension-related example is that of patient-funded clinical trials. At such an early stage, experimental rejuvenation therapies are indeed expensive, and governments may not be willing to pay for what seems like a moon shot. Thus, wealthy people willing to pay to try the therapies are effectively making it easier to test them.

Some people may argue that wealthy people are doing this not to help the research but for their own benefit; consequently, they feel outraged and despise the idea of patient-funded entirely, deeming it nothing but proof that rejuvenation is only for the rich.

However, regardless of the motives that push rich people to pay for these experimental treatment, the fact is that the treatments are experimental indeed; it’s as of yet unknown whether they’re even safe in humans, let alone if they yield any benefit. Effectively, these rich people are paying to be guinea pigs, even though they’re doing it for potential personal benefits rather than for the greater good.

Similarly, someone might think that life extension advocates are pushing to have aging cured only because they don’t want to die, not because they’re interested in reducing the suffering of the elderly. Whether this is the true motive depends on individual advocates, but it’s immaterial—whatever their reasons may be, their actions are helping to make rejuvenation a reality, which may, in turn, reduce the suffering of millions.

The takeaway here is that anyone’s motives for endorsing an idea are irrelevant when assessing whether the idea is good or not.

Appeal to authority

The infamous appeal to authority involves believing a claim solely because the person who made it is in a position of authority or prestige. The underlying assumption is that, by virtue of his or her status alone, this person must be right, either because he or she can’t make a mistake or is assumed to have verified the claim in question.

A variant of this fallacy, called the appeal to false authority, is committed when the person on whose authority one is relying isn’t competent in a relevant field—for example, believing a claim about economics made by a famous physicist simply because that person is a famous physicist constitutes appeal to false authority, because the field of expertise of the physicist isn’t relevant to economics and hence is not an authority in this field.

Needless to say, everyone can make a mistake, no matter how smart, authoritative, or knowledgeable he or she may be. You don’t take for granted what Albert Einstein said because he was one of the greatest physicists of all time; his claims, too, need proof, and until said proof is presented and verified, you can’t say whether the claim is true or false.

When discussing rejuvenation, the appeal to authority fallacy is sometimes observed when people say that rejuvenation isn’t possible because an expert said so. The expert in question might well be right, but in order to establish it, his evidence must be examined to make sure that he isn’t genuinely mistaken or doesn’t have some other reason to make an unsubstantiated claim.

It’s important to notice that relying on the opinion of experts isn’t always the same as appeal to authority; for example, we routinely trust our doctor when she prescribes us a drug. However, we’re not simply taking her word that she is a qualified doctor; the fact she has other, satisfied patients and a valid license are some ways that we can know that our doctor is trustworthy. Additionally, she’s basing her diagnosis on tests and checkups that can be independently verified; if we’re not convinced of the diagnosis of our doctor, we can always turn to another one for a second opinion.

Naturalistic fallacy (or is-ought fallacy)

The naturalistic fallacy, which is not the same as the appeal to nature, is committed whenever we assume that the way things are is the way they ought to be.

A luckily outdated example of the naturalistic fallacy is that of infant mortality. Back when most children never reached adulthood, a person could have erroneously concluded that since high infant mortality existed, it ought to have existed; today, you wouldn’t make many friends if you held this belief.

In the context of life extension, this fallacy is observed when people say that aging and dying is the way that things should be simply because that’s how they are right now. This fallacy can be countered easily by bringing up examples of things that exist but ought not to, such as murders, rapes, and wars.

Appeal to nature

The appeal to nature claims that all which is natural is generally better than what is not natural, and vice versa, or that natural equals good while unnatural equals bad.

In the context of life extension, as aging is natural and rejuvenation therapies are not, this fallacy manifests in the belief that aging is better or more desirable than using rejuvenative therapies to avoid aging.

The appeal to nature fallacy is again easily countered with examples of perfectly natural things that aren’t desirable or good, such as infectious diseases and calamities, and unnatural things that are desirable, such as medicines, apartments, and machines.

Appeal to normality

This fallacy is committed when one concludes that which conforms to current social norms is the standard of goodness, and conversely, all that is not the norm is bad. For example, being obese is bad for you, whether or not most people are obese where you live, which makes obesity a norm. Inferring that being obese is okay because most people are obese constitutes an appeal to normality.

In the context of aging and life extension, one might commit this fallacy by claiming that, given that it’s normal to have high blood pressure in old age, there’s nothing wrong with it, even though high blood pressure is bad for you; similarly, as it is currently normal to die well before age 110, one could incorrectly infer that it’s good to die before age 110 and bad to live longer than that.

“Normal” only refers to what is commonly observed in a given population or context; it says nothing about whether that which is commonly observed is good, bad, desirable, or undesirable. This fallacy can be countered by providing examples of things that are normal in a certain frame of reference and yet obviously bad—e.g., it’s perfectly normal that many lives are lost during war, yet it’s not good nor desirable.

Appeal to self-evident truth

This fallacy is committed whenever a claim is presented, without proof, to be a self-evident truth when, in fact, it isn’t. Such claims are are often clichés that have been perpetuated long enough to feel like common sense though they have no or weak justification.

An example is the phrase “You can’t appreciate a good thing until you lose it”; while it may certainly happen that you fail to notice something until that something isn’t there anymore, this sentence is logically equivalent to “If you appreciate a good thing, then you must have lost it” (because if you hadn’t lost it, then by assumption you wouldn’t be able to appreciate it); however, there are no grounds to say that, in general, everyone can never appreciate his or her own health, the love of a companion, or any other good thing.

In the context of life extension, the typical examples are “death gives life meaning”, “we should make room for new generations”, “living forever would be boring”, and similar phrases. These are all claims that may feel vaguely or intuitively true, again often because they’ve been repeated ad nauseam or because they appeal to the alleged wisdom of accepting death.

In general, appeal to self-evident truth is countered by pointing out that what is self-evident to someone may not be to someone else and that evidence must always be provided to back claims up.

The specific life extension-related examples above may also be countered with simple observations. For example, meaning is not an intrinsic property and depends on an observer, so death cannot be a necessary or sufficient condition to give everyone’s life meaning; for different people, life can be meaningful without death (for example, you may find meaning in doing something that gives you satisfaction), and yet other people might find that death is necessary for their lives to have meaning but that they also need more than just that.

Boredom cannot be assumed to be a given of a long life, for example, because it’s uncertain whether more forms of ludic or intellectual entertainment will be available in the future; the concept of having to make room for future generations rests on shaky grounds, as there is no proof that the death of current generations is necessary for the sake of future ones, nor is it reasonable to ask existing people to give up on health and life for the sake of people who do not actually exist yet.

Appeal to worse problems

Also known as the fallacy of relative privation, this is the mistake of that claiming a given problem is not very serious because there are other, allegedly worse problems, ultimately in an attempt to belittle or discount the original problem.

One example would be if you are told to be happy with your unfulfilling job because so many other people don’t even have any and are thus worse off; these people may well have a more serious problem than yours, but this doesn’t mean that being stuck in a job you dislike isn’t a problem worth of consideration.

This fallacy is problematic on different levels. First, the gravity of a problem is often hard to establish objectively; different people may have different opinions on how serious a problem is or which problem is more serious than which. Secondly, even assuming ordering problems by seriousness in an universally accepted manner was possible, a problem may well be less serious than others, and yet be extremely serious; the fact  that 10 sextillion is smaller than 10 sextillion and one doesn’t make it a small number—just smaller than the other one.

It the context of life extension, this fallacy is often committed by saying there are worse problems than aging and therefore that we should dedicate our resources to solving those instead. This claim can be countered in different ways. You can point out the fact that aging kills more people than all other causes of death combined (roughly 100,000 out of 150,000 people a day), often after decades of suffering and reduced independence, and it may thus be argued that it is the most serious problem in terms of lives lost; you can also observe that dedicating resources to defeating aging doesn’t automatically imply that other problems can’t be dealt with as well. (This is a case of  false dichotomy—the fallacious assumption that only two mutually exclusive options are available when, in fact, there are more.)

Slippery slope

Slippery slope is the fallacy by which a relatively insignificant initial event is assumed to lead to subsequent, increasingly more catastrophic and improbable events in a sort of chain reaction; A leads to B leads to C, and so on, until the final event is an extremely negative end result.

For example, suppose you went out and left your umbrella home. If it rained, you’d get wet, which might make you catch a cold, which might turn into pneumonia, which might cause you to be bedridden for three weeks, which might prevent you from sitting an important exam, which might jeopardize your academic timetable for the year, which might stress you out to the point of dropping out of college, which might lead you to a job you hate, which might ruin your life. None of this is impossible, but not especially likely either; being paranoid about not forgetting your umbrella at home because your life might be ruined definitely involves the slippery slope fallacy.

In the context of life extension, the slippery slope is sometimes observed when people imagine the possible catastrophic consequences of defeating aging without really having a good grasp of the probabilities of each hypothetical step involved. For example, if we defeat aging, then there might be a sudden increase in the population, which might lead to fighting over resources, which might exacerbate pre-existing conflicts, which might lead to the collapse of political coalitions, which might result in World War III, which might result in near-annihilation of the human race.

Again, none of this is certified to be 100% impossible, but assuming that this chain of events is likely enough to justify not defeating aging is a slippery slope; to have a vaguely reasonable estimate of the probability of such a disastrous chain reaction to happen, one would have to take into account the variation in the probability of each individual step as time goes by (given the magnitude of each event, we’re talking about a timeline of several decades), which, in turn, depends on our ability to prevent, or mitigate the effects of, each event along the way; this also depends on unknown factors, such as future political situation, technological progress, etc.

In short, the probability of catastrophic events following the defeat of aging isn’t known with enough precision to justify inaction; on the other hand, the fact that aging kills thousands and causes the suffering of millions on a daily basis is well established and justifies action against aging.

False analogy

This fallacy arises when an incorrect analogy is used to try to prove or disprove an argument. Such analogy might appear sensible at first, but the terms of comparison eventually turn out to be too dissimilar. A false analogy is disproved by pointing out how the two terms of comparison are too different for the comparison itself to be meaningful.

A textbook example of this fallacy is comparing evolution to a twister assembling a fully functional 747 from parts. This false analogy emphasizes randomness—which is a critical component of evolution, in that small, random mutations are key to it—but fails to account for natural selection, by which mutations that are unfavorable in a creature’s environment are weeded out through the death of the unfortunate creature.

In the context of life extension, a false analogy is often drawn between life and good things in it, claiming that as you eventually get enough of good things (even though there are counterexamples, such as good health), you’ll eventually get enough of life, it being a good thing as well, and thus you’ll necessarily want to die or need death in order to appreciate life. As life is not a single thing, but rather a collection of events, experiences, etc, which can all vary and regain novelty value, the analogy is flawed.

Another typical false analogy is drawn between aging and a sunset. Both of them involve a gradual descent, but that’s all they share—a sunset doesn’t lead to the death of the Sun, nor does a person come back after dying of aging. Aging is a decline in health and function, while a sunset is a part of the apparent motion of the Sun around the Earth. This false analogy is often used to imply that aging produces the same feelings of awe, bliss, peace, and tranquillity that a sunset may inspire; however, if such feelings are experienced in old age, this is more likely to be due to life experiences accrued thus far, rather than one’s own deteriorating health.

False dilemma

A false dilemma, or false dichotomy, happens whenever two mutually exclusive options are presented as the only ones, even though others are possible too. Examples typically involve ideologies or philosophical positions, such as adherence to a religion, feminism, or a political party: either you believe in God or you are evil; either you’re a feminist or you are in favor of oppressing women; either you side with political party P or you’re against freedom. In essence, the false dilemma fallacy reduces a specter of possible positions down to two extremes.

Generally speaking, this fallacy is countered by providing examples of options between the two extremes, such as an atheist dedicating his life to helping people in need.

Regarding life extension, the false dilemma manifests when undesirable outcomes are presented as inescapable side effects of defeating aging or researching life extension; a typical example is the implicit assumption made by people who think that we should focus our efforts on problems that are supposedly worse than aging: either we dedicate ourselves to solving aging or to other problems. However, just as nothing prevents us from working on starving children and climate change at the same time, we can work on aging and the rest of the global issues simultaneously.

Another example is the following reasoning: “Either we don’t defeat aging and stave off cultural stagnation, or we do defeat aging and put up with cultural stagnation.” The idea that these are the only options and that there will be no middle ground where aging is defeated but cultural stagnation is either prevented or mitigated constitutes a false dilemma; for example, assuming that the presence of very long-lived individuals necessarily leads to stagnation (which is uncertain at this stage and might well not happen if brain plasticity is sufficiently preserved by comprehensive rejuvenation), there is still the option of mitigating the problem through social programs that provide continuous learning.

Appeal to anger

This fallacy attempts to justify an argument based solely on negative emotions. Typically, this involves rejecting an argument only because someone is outraged or enraged by it without any actual evidence against the argument having been presented.

Examples of this fallacy are plentiful in populist speech urging votes for a certain candidate, even if said speech provided no evidence than voting for that candidate will solve any problem.

In life extension, a common example is that of death as an equalizer. The argument hinges on the premise that life extension will only be a privilege for First World people; the idea that such people could enjoy indefinite lifespans while people in developing countries can barely live out normal lives causes outrage, often among First Worlders themselves, who end up discounting rejuvenation in the name of social justice. The outrage is even greater if the privileged people who get rejuvenation are assumed to be only “the rich”.

Even if we accept the (debatable) premise of the argument, this is still fallacious in that not developing rejuvenation doesn’t improve the lives of poor people, nor would developing it worsen their condition. Thus, the reason behind the refusal of rejuvenation is nothing but outrage alone, hence the fallacy.

These are only the most frequent examples of fallacies that you may bump into when discussing life extension, and it shouldn’t be considered an exhaustive list. Remember that this list is meant as a tool to help you spot and refute logical fallacies. However, to get your message across, you should never simply accuse your interlocutor of fallacious reasoning but rather show how and why his or her argument is invalid. The point of advocacy is to convey a message, not to prove your opponent wrong.

About the author

Nicola Bagalà

Nicola is a bit of a jack of all trades—a holder of an M.Sc. in mathematics; an amateur programmer; a hobbyist at novel writing, piano and art; and, of course, a passionate life extensionist. After his interest in the science of undoing aging arose in 2011, he gradually shifted from quiet supporter to active advocate in 2015, first launching his advocacy blog Rejuvenaction before eventually joining LEAF. These years in the field sparked an interest in molecular biology, which he actively studies. Other subjects he loves to discuss to no end are cosmology, artificial intelligence, and many others—far too many for a currently normal lifespan, which is one of the reasons he’s into life extension.
  1. August 29, 2018

    It’s an amazing article for all the web people; they will obtain advantage from it
    I am sure.

  2. September 3, 2018

    Thank you for this article.
    It’s hard not to lose patience when confronted to these arguments, because they are often used one after the other as a weapon. They are not brought up as legitimate concerns, but rather as excuses to deflect the idea that we could live forever. It’s sad having to fight to promote a concept that’ll save billions of lives.

  3. September 14, 2018

    Useful post for convincing people of the rightfulness of behaving in favor of the anti-aging research.

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