Doomsday argument

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https://en.wikipedia.org/wiki/Doomsday_argument

World population from 10,000 BC to AD 2000

The doomsday argument (DA), or Carter catastrophe, is a probabilistic argument that claims to predict the future population of the human species based on an estimation of the number of humans born to date. The doomsday argument was originally proposed by the astrophysicist Brandon Carter in 1983, leading to the initial name of the Carter catastrophe. The argument was subsequently championed by the philosopher John A. Leslie and has since been independently conceived by J. Richard Gott and Holger Bech Nielsen. Similar principles of eschatology were proposed earlier by Heinz von Foerster, among others. A more general form was given earlier in the Lindy effect, which proposes that for certain phenomena, the future life expectancy is proportional to (though not necessarily equal to) the current age and is based on a decreasing mortality rate over time.

Summary

The premise of the argument is as follows: suppose that the total number of human beings that will ever exist is fixed. If so, the likelihood of a randomly selected person existing at a particular time in history would be proportional to the total population at that time. Given this, the argument posits that a person alive today should adjust their expectations about the future of the human race because their existence provides information about the total number of humans that will ever live.

If the total number of humans who were born or will ever be born is denoted by $N$, then the Copernican principle suggests that any one human is equally likely (along with the other $N-1$ humans) to find themselves in any position $n$ of the total population $N$so humans assume that our fractional position $f=n/N$ is uniformly distributed on the interval [0,1] before learning our absolute position.

$f$ is uniformly distributed on (0,1) even after learning the absolute position $n$. For example, there is a 95% chance that $f$ is in the interval (0.05,1), that is $f>0.05$. In other words, one can assume with 95% certainty that any individual human would be within the last 95% of all the humans ever to be born. If the absolute position $n$ is known, this argument implies a 95% confidence upper bound for $N$ obtained by rearranging $n/N>0.05$ to give $N<20n$.

If Leslie's figure is used, then approximately 60 billion humans have been born so far, so it can be estimated that there is a 95% chance that the total number of humans $N$ will be less than 20$\times$60 billion = 1.2 trillion. Assuming that the world population stabilizes at 10 billion and a life expectancy of 80 years, it can be estimated that the remaining 1140 billion humans will be born in 9120 years. Depending on the projection of the world population in the forthcoming centuries, estimates may vary, but the argument states that it is unlikely that more than 1.2 trillion humans will ever live.

Aspects

Assume, for simplicity, that the total number of humans who will ever be born is 60 billion (N₁), or 6,000 billion (N₂). If there is no prior knowledge of the position that a currently living individual, X, has in the history of humanity, one may instead compute how many humans were born before X, and arrive at say 59,854,795,447, which would necessarily place X among the first 60 billion humans who have ever lived.

It is possible to sum the probabilities for each value of N and, therefore, to compute a statistical 'confidence limit' on N. For example, taking the numbers above, it is 99% certain that N is smaller than 6 trillion.

Note that as remarked above, this argument assumes that the prior probability for N is flat, or 50% for N₁ and 50% for N₂ in the absence of any information about X. On the other hand, it is possible to conclude, given X, that N₂ is more likely than N₁ if a different prior is used for N. More precisely, Bayes' theorem tells us that P(N|X) = P(X|N)P(N)/P(X), and the conservative application of the Copernican principle tells us only how to calculate P(X|N). Taking P(X) to be flat, we still have to assume the prior probability P(N) that the total number of humans is N. If we conclude that N₂ is much more likely than N₁ (for example, because producing a larger population takes more time, increasing the chance that a low probability but cataclysmic natural event will take place in that time), then P(X|N) can become more heavily weighted towards the bigger value of N. A further, more detailed discussion, as well as relevant distributions P(N), are given below in the Rebuttals section.

The doomsday argument does not say that humanity cannot or will not exist indefinitely. It does not put any upper limit on the number of humans that will ever exist nor provide a date for when humanity will become extinct. An abbreviated form of the argument does make these claims, by confusing probability with certainty. However, the actual conclusion for the version used above is that there is a 95% chance of extinction within 9,120 years and a 5% chance that some humans will still be alive at the end of that period. (The precise numbers vary among specific doomsday arguments.)

Variations

This argument has generated a philosophical debate, and no consensus has yet emerged on its solution. The variants described below produce the DA by separate derivations.

Gott's formulation: "vague prior" total population

Gott specifically proposes the functional form for the prior distribution of the number of people who will ever be born (N). Gott's DA used the vague prior distribution:

${\displaystyle P(N)=\frac{k}{N}}$.

where

• P(N) is the probability prior to discovering n, the total number of humans who have yet been born.
• The constant, k, is chosen to normalize the sum of P(N). The value chosen is not important here, just the functional form (this is an improper prior, so no value of k gives a valid distribution, but Bayesian inference is still possible using it.)

Since Gott specifies the prior distribution of total humans, P(N), Bayes' theorem and the principle of indifference alone give us P(N|n), the probability of N humans being born if n is a random draw from N:

${\displaystyle P(N\mid n)=\frac{P(n\mid N)P(N)}{P(n)}.}$

This is Bayes' theorem for the posterior probability of the total population ever born of N, conditioned on population born thus far of n. Now, using the indifference principle:

${\displaystyle P(n\mid N)=\frac{1}{N}}$.

The unconditioned n distribution of the current population is identical to the vague prior N probability density function, so:

${\displaystyle P(n)=\frac{k}{n}}$,

giving P (N | n) for each specific N (through a substitution into the posterior probability equation):

${\displaystyle P(N\mid n)=\frac{n}{N^2}}$.

The easiest way to produce the doomsday estimate with a given confidence (say 95%) is to pretend that N is a continuous variable (since it is very large) and integrate over the probability density from N = n to N = Z. (This will give a function for the probability that N ≤ Z):

${\displaystyle P(N\le Z)={\int }_{N=n}^{N=Z}P(N|n)dN}$ ${\displaystyle =\frac{Z-n}{Z}}$

Defining Z = 20n gives:

${\displaystyle P(N\le 20n)=\frac{19}{20}}$.

This is the simplest Bayesian derivation of the doomsday argument:

The chance that the total number of humans that will ever be born (N) is greater than twenty times the total that have been is below 5%

The use of a vague prior distribution seems well-motivated as it assumes as little knowledge as possible about N, given that some particular function must be chosen. It is equivalent to the assumption that the probability density of one's fractional position remains uniformly distributed even after learning of one's absolute position (n).

Gott's "reference class" in his original 1993 paper was not the number of births, but the number of years "humans" had existed as a species, which he put at 200,000. Also, Gott tried to give a 95% confidence interval between a minimum survival time and a maximum. Because of the 2.5% chance that he gives to underestimating the minimum, he has only a 2.5% chance of overestimating the maximum. This equates to 97.5% confidence that extinction occurs before the upper boundary of his confidence interval, which can be used in the integral above with Z = 40n, and n = 200,000 years:

${\displaystyle P(N\le 40[200000])=\frac{39}{40}}$

This is how Gott produces a 97.5% confidence of extinction within N ≤ 8,000,000 years. The number he quoted was the likely time remaining, N − n = 7.8 million years. This was much higher than the temporal confidence bound produced by counting births, because it applied the principle of indifference to time. (Producing different estimates by sampling different parameters in the same hypothesis is Bertrand's paradox.) Similarly, there is a 97.5% chance that the present lies in the first 97.5% of human history, so there is a 97.5% chance that the total lifespan of humanity will be at least

${\displaystyle N\ge 200000\times \frac{40}{39}\approx 205100\text{years}}$;

In other words, Gott's argument gives a 95% confidence that humans will go extinct between 5,100 and 7.8 million years in the future.

Gott has also tested this formulation against the Berlin Wall and Broadway and off-Broadway plays.

Leslie's argument differs from Gott's version in that he does not assume a vague prior probability distribution for N. Instead, he argues that the force of the doomsday argument resides purely in the increased probability of an early doomsday once you take into account your birth position, regardless of your prior probability distribution for N. He calls this the probability shift.

Heinz von Foerster argued that humanity's abilities to construct societies, civilizations and technologies do not result in self-inhibition. Rather, societies' success varies directly with population size. Von Foerster found that this model fits some 25 data points from the birth of Jesus to 1958, with only 7% of the variance left unexplained. Several follow-up letters (1961, 1962, ...) were published in Science showing that von Foerster's equation was still on track. The data continued to fit up until 1973. The most remarkable thing about von Foerster's model was it predicted that the human population would reach infinity or a mathematical singularity, on Friday, November 13, 2026. In fact, von Foerster did not imply that the world population on that day could actually become infinite. The real implication was that the world population growth pattern followed for many centuries prior to 1960 was about to come to an end and be transformed into a radically different pattern. Note that this prediction began to be fulfilled just in a few years after the "doomsday" argument was published.

Reference classes

The reference class from which n is drawn, and of which N is the ultimate size, is a crucial point of contention in the doomsday argument argument. The "standard" doomsday argument hypothesis skips over this point entirely, merely stating that the reference class is the number of "people". Given that you are human, the Copernican principle might be used to determine if you were born exceptionally early, however the term "human" has been heavily contested on practical and philosophical reasons. According to Nick Bostrom, consciousness is (part of) the discriminator between what is in and what is out of the reference class, and therefore extraterrestrial intelligence might have a significant impact on the calculation.

The following sub-sections relate to different suggested reference classes, each of which has had the standard doomsday argument applied to it.

SSSA: Sampling from observer-moments

Nick Bostrom, considering observation selection effects, has produced a Self-Sampling Assumption (SSA): "that you should think of yourself as if you were a random observer from a suitable reference class". If the "reference class" is the set of humans to ever be born, this gives N < 20n with 95% confidence (the standard doomsday argument). However, he has refined this idea to apply to observer-moments rather than just observers. He has formalized this as:

The strong self-sampling assumption (SSSA): Each observer-moment should reason as if it were randomly selected from the class of all observer-moments in its reference class.

An application of the principle underlying SSSA (though this application is nowhere expressly articulated by Bostrom), is: If the minute in which you read this article is randomly selected from every minute in every human's lifespan, then (with 95% confidence) this event has occurred after the first 5% of human observer-moments. If the mean lifespan in the future is twice the historic mean lifespan, this implies 95% confidence that N < 10n (the average future human will account for twice the observer-moments of the average historic human). Therefore, the 95th percentile extinction-time estimate in this version is 4560 years.

Rebuttals

We are in the earliest 5%, a priori

One counterargument to the doomsday argument agrees with its statistical methods but disagrees with its extinction-time estimate. This position requires justifying why the observer cannot be assumed to be randomly selected from the set of all humans ever to be born, which implies that this set is not an appropriate reference class. By disagreeing with the doomsday argument, it implies that the observer is within the first 5% of humans to be born.

By analogy, if one is a member of 50,000 people in a collaborative project, the reasoning of the doomsday argument implies that there will never be more than a million members of that project, within a 95% confidence interval. However, if one's characteristics are typical of an early adopter, rather than typical of an average member over the project's lifespan, then it may not be reasonable to assume one has joined the project at a random point in its life. For instance, the mainstream of potential users will prefer to be involved when the project is nearly complete. However, if one were to enjoy the project's incompleteness, it is already known that he or she is unusual, before the discovery of his or her early involvement.

If one has measurable attributes that set one apart from the typical long-run user, the project doomsday argument can be refuted based on the fact that one could expect to be within the first 5% of members, a priori. The analogy to the total-human-population form of the argument is that confidence in a prediction of the distribution of human characteristics that places modern and historic humans outside the mainstream implies that it is already known, before examining n, that it is likely to be very early in N. This is an argument for changing the reference class.

For example, if one is certain that 99% of humans who will ever live will be cyborgs, but that only a negligible fraction of humans who have been born to date are cyborgs, one could be equally certain that at least one hundred times as many people remain to be born as have been.

Robin Hanson's paper sums up these criticisms of the doomsday argument:

All else is not equal; we have good reasons for thinking we are not randomly selected humans from all who will ever live.

Human extinction is distant, a posteriori

The a posteriori observation that extinction level events are rare could be offered as evidence that the doomsday argument's predictions are implausible; typically, extinctions of dominant species happen less often than once in a million years. Therefore, it is argued that human extinction is unlikely within the next ten millennia. (Another probabilistic argument, drawing a different conclusion than the doomsday argument.)

In Bayesian terms, this response to the doomsday argument says that our knowledge of history (or ability to prevent disaster) produces a prior marginal for N with a minimum value in the trillions. If N is distributed uniformly from 10¹² to 10¹³, for example, then the probability of N < 1,200 billion inferred from n = 60 billion will be extremely small. This is an equally impeccable Bayesian calculation, rejecting the Copernican principle because we must be 'special observers' since there is no likely mechanism for humanity to go extinct within the next hundred thousand years.

This response is accused of overlooking the technological threats to humanity's survival, to which earlier life was not subject, and is specifically rejected by most academic critics of the doomsday argument (arguably excepting Robin Hanson).

The prior N distribution may make n very uninformative

Robin Hanson argues that N's prior may be exponentially distributed:

${\displaystyle N=\frac{e^{U(0,q]}}{c}}$

Here, c and q are constants. If q is large, then our 95% confidence upper bound is on the uniform draw, not the exponential value of N.

The simplest way to compare this with Gott's Bayesian argument is to flatten the distribution from the vague prior by having the probability fall off more slowly with N (than inverse proportionally). This corresponds to the idea that humanity's growth may be exponential in time with doomsday having a vague prior probability density function in time. This would mean that N, the last birth, would have a distribution looking like the following:

${\displaystyle Pr(N)=\frac{k}{N^{\alpha }},0<\alpha <1.}$

This prior N distribution is all that is required (with the principle of indifference) to produce the inference of N from n, and this is done in an identical way to the standard case, as described by Gott (equivalent to ${\displaystyle \alpha }$ = 1 in this distribution):

${\displaystyle Pr(n)={\int }_{N=n}^{N=\mathrm{\infty }}Pr(n\mid N)Pr(N)dN={\int }_n^{\mathrm{\infty }}\frac{k}{N^{(\alpha +1)}}dN=\frac{k}{\alpha n^{\alpha }}}$

Substituting into the posterior probability equation):

${\displaystyle Pr(N\mid n)=\frac{\alpha n^{\alpha }}{N^{(1+\alpha )}}.}$

Integrating the probability of any N above xn:

${\displaystyle Pr(N>xn)={\int }_{N=xn}^{N=\mathrm{\infty }}Pr(N\mid n)dN=\frac{1}{x^{\alpha }}.}$

For example, if x = 20, and ${\displaystyle \alpha }$ = 0.5, this becomes:

${\displaystyle Pr(N>20n)=\frac{1}{\sqrt{20}}\simeq 22.3\mathrm{\%}.}$

Therefore, with this prior, the chance of a trillion births is well over 20%, rather than the 5% chance given by the standard DA. If ${\displaystyle \alpha }$ is reduced further by assuming a flatter prior N distribution, then the limits on N given by n become weaker. An ${\displaystyle \alpha }$ of one reproduces Gott's calculation with a birth reference class, and ${\displaystyle \alpha }$ around 0.5 could approximate his temporal confidence interval calculation (if the population were expanding exponentially). As ${\displaystyle \alpha \to 0}$ (gets smaller) n becomes less and less informative about N. In the limit this distribution approaches an (unbounded) uniform distribution, where all values of N are equally likely. This is Page et al.'s "Assumption 3", which they find few reasons to reject, a priori. (Although all distributions with ${\displaystyle \alpha \le 1}$ are improper priors, this applies to Gott's vague-prior distribution also, and they can all be converted to produce proper integrals by postulating a finite upper population limit.) Since the probability of reaching a population of size 2N is usually thought of as the chance of reaching N multiplied by the survival probability from N to 2N it follows that Pr(N) must be a monotonically decreasing function of N, but this doesn't necessarily require an inverse proportionality.

Infinite expectation

Another objection to the doomsday argument is that the expected total human population is actually infinite. The calculation is as follows:

The total human population N = n/f, where n is the human population to date and f is our fractional position in the total.

We assume that f is uniformly distributed on (0,1].

The expectation of N is $${\displaystyle E(N)={\int }_0^1\frac{n}{f}df=n[\ln (f){]}_0^1=n\ln (1)-n\ln (0)=+\mathrm{\infty }.}$$

For a similar example of counterintuitive infinite expectations, see the St. Petersburg paradox.

Self-indication assumption: The possibility of not existing at all

Main article: Self-indication assumption doomsday argument rebuttal

One objection is that the possibility of a human existing at all depends on how many humans will ever exist (N). If this is a high number, then the possibility of their existing is higher than if only a few humans will ever exist. Since they do indeed exist, this is evidence that the number of humans that will ever exist is high.

This objection, originally by Dennis Dieks (1992), is now known by Nick Bostrom's name for it: the "Self-Indication Assumption objection". It can be shown that some SIAs prevent any inference of N from n (the current population).

Caves' rebuttal

The Bayesian argument by Carlton M. Caves states that the uniform distribution assumption is incompatible with the Copernican principle, not a consequence of it.

Caves gives a number of examples to argue that Gott's rule is implausible. For instance, he says, imagine stumbling into a birthday party, about which you know nothing:

Your friendly enquiry about the age of the celebrant elicits the reply that she is celebrating her (t_p=) 50th birthday. According to Gott, you can predict with 95% confidence that the woman will survive between [50]/39 = 1.28 years and 39[×50] = 1,950 years into the future. Since the wide range encompasses reasonable expectations regarding the woman's survival, it might not seem so bad, till one realizes that [Gott's rule] predicts that with probability 1/2 the woman will survive beyond 100 years old and with probability 1/3 beyond 150. Few of us would want to bet on the woman's survival using Gott's rule. (See Caves' online paper below.)

Although this example exposes a weakness in J. Richard Gott's "Copernicus method" DA (that he does not specify when the "Copernicus method" can be applied) it is not precisely analogous with the modern DA; epistemological refinements of Gott's argument by philosophers such as Nick Bostrom specify that:

Knowing the absolute birth rank (n) must give no information on the total population (N).

Careful DA variants specified with this rule aren't shown implausible by Caves' "Old Lady" example above, because the woman's age is given prior to the estimate of her lifespan. Since human age gives an estimate of survival time (via actuarial tables) Caves' Birthday party age-estimate could not fall into the class of DA problems defined with this proviso.

To produce a comparable "Birthday Party Example" of the carefully specified Bayesian DA, we would need to completely exclude all prior knowledge of likely human life spans; in principle this could be done (e.g.: hypothetical Amnesia chamber). However, this would remove the modified example from everyday experience. To keep it in the everyday realm the lady's age must be hidden prior to the survival estimate being made. (Although this is no longer exactly the DA, it is much more comparable to it.)

Without knowing the lady's age, the DA reasoning produces a rule to convert the birthday (n) into a maximum lifespan with 50% confidence (N). Gott's Copernicus method rule is simply: Prob (N < 2n) = 50%. How accurate would this estimate turn out to be? Western demographics are now fairly uniform across ages, so a random birthday (n) could be (very roughly) approximated by a U(0,M] draw where M is the maximum lifespan in the census. In this 'flat' model, everyone shares the same lifespan so N = M. If n happens to be less than (M)/2 then Gott's 2n estimate of N will be under M, its true figure. The other half of the time 2n underestimates M, and in this case (the one Caves highlights in his example) the subject will die before the 2n estimate is reached. In this "flat demographics" model Gott's 50% confidence figure is proven right 50% of the time.

Self-referencing doomsday argument rebuttal

Main article: Self-referencing doomsday argument rebuttal

Some philosophers have suggested that only people who have contemplated the doomsday argument (DA) belong in the reference class "human". If that is the appropriate reference class, Carter defied his own prediction when he first described the argument (to the Royal Society). An attendant could have argued thus:

Presently, only one person in the world understands the Doomsday argument, so by its own logic there is a 95% chance that it is a minor problem which will only ever interest twenty people, and I should ignore it.

Jeff Dewynne and Professor Peter Landsberg suggested that this line of reasoning will create a paradox for the doomsday argument:

If a member of the Royal Society did pass such a comment, it would indicate that they understood the DA sufficiently well that in fact 2 people could be considered to understand it, and thus there would be a 5% chance that 40 or more people would actually be interested. Also, of course, ignoring something because you only expect a small number of people to be interested in it is extremely short sighted—if this approach were to be taken, nothing new would ever be explored, if we assume no a priori knowledge of the nature of interest and attentional mechanisms.

Conflation of future duration with total duration

Various authors have argued that the doomsday argument rests on an incorrect conflation of future duration with total duration. This occurs in the specification of the two time periods as "doom soon" and "doom deferred" which means that both periods are selected to occur after the observed value of the birth order. A rebuttal in Pisaturo (2009) argues that the doomsday argument relies on the equivalent of this equation:

${\displaystyle P(H_{TS}|D_{p}X)/P(H_{TL}|D_{p}X)=[P(H_{FS}|X)/P(H_{FL}|X)]\cdot [P(D_p|H_{TS}X)/P(D_p|H_{TL}X)]}$,

where:

X = the prior information;

D_p = the data that past duration is t_p;

H_FS = the hypothesis that the future duration of the phenomenon will be short;

H_FL = the hypothesis that the future duration of the phenomenon will be long;

H_TS = the hypothesis that the total duration of the phenomenon will be short—i.e., that t_t, the phenomenon's total longevity, = t_TS;

H_TL = the hypothesis that the total duration of the phenomenon will be long—i.e., that t_t, the phenomenon's total longevity, = t_TL, with t_TL > t_TS.

Pisaturo then observes:

Clearly, this is an invalid application of Bayes' theorem, as it conflates future duration and total duration.

Pisaturo takes numerical examples based on two possible corrections to this equation: considering only future durations and considering only total durations. In both cases, he concludes that the doomsday argument's claim, that there is a "Bayesian shift" in favor of the shorter future duration, is fallacious.

This argument is also echoed in O'Neill (2014). In this work O'Neill argues that a unidirectional "Bayesian Shift" is an impossibility within the standard formulation of probability theory and is contradictory to the rules of probability. As with Pisaturo, he argues that the doomsday argument conflates future duration with total duration by specification of doom times that occur after the observed birth order. According to O'Neill:

The reason for the hostility to the doomsday argument and its assertion of a "Bayesian shift" is that many people who are familiar with probability theory are implicitly aware of the absurdity of the claim that one can have an automatic unidirectional shift in beliefs regardless of the actual outcome that is observed. This is an example of the "reasoning to a foregone conclusion" that arises in certain kinds of failures of an underlying inferential mechanism. An examination of the inference problem used in the argument shows that this suspicion is indeed correct, and the doomsday argument is invalid. (pp. 216-217)

Confusion over the meaning of confidence intervals

Gelman and Robert assert that the doomsday argument confuses frequentist confidence intervals with Bayesian credible intervals. Suppose that every individual knows their number n and uses it to estimate an upper bound on N. Every individual has a different estimate, and these estimates are constructed so that 95% of them contain the true value of N and the other 5% do not. This, say Gelman and Robert, is the defining property of a frequentist lower-tailed 95% confidence interval. But, they say, "this does not mean that there is a 95% chance that any particular interval will contain the true value." That is, while 95% of the confidence intervals will contain the true value of N, this is not the same as N being contained in the confidence interval with 95% probability. The latter is a different property and is the defining characteristic of a Bayesian credible interval. Gelman and Robert conclude:

the Doomsday argument is the ultimate triumph of the idea, beloved among Bayesian educators, that our students and clients do not really understand Neyman–Pearson confidence intervals and inevitably give them the intuitive Bayesian interpretation.

Afrocentrism

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Afrocentrism

Afrocentrism is a worldview that is centered on the history of people of African descent or a biased view that favors it over non-African civilizations. It is in some respects a response to Eurocentric attitudes about African people and their historical contributions. It seeks to counter what it sees as mistakes and ideas perpetuated by the racist philosophical underpinnings of Western academic disciplines as they developed during and since Europe's Early Renaissance as justifying rationales for the enslavement of other peoples, in order to enable more accurate accounts of not only African but all people's contributions to world history. Afrocentricity deals primarily with self-determination and African agency and is a pan-African point of view for the study of culture, philosophy, and history.

Afrocentrism is a scholarly movement that seeks to conduct research and education on global history subjects, from the perspective of historical African peoples and polities. It takes a critical stance on Eurocentric assumptions and myths about world history, in order to pursue methodological studies of the latter. Some of the critics of the movement believe that it often denies or minimizes European, Near Eastern, and Asian cultural influences while exaggerating certain aspects of historical African civilizations that independently accomplished a significant level of cultural and technological development. In general, Afrocentrism is usually manifested in a focus on the history of Africa and its role in contemporary African-American culture among others.

What is today broadly called Afrocentrism evolved out of the work of African American intellectuals in the late nineteenth and early twentieth centuries, but flowered into its modern form due to the activism of African American intellectuals in the U.S. civil rights movement and in the development of African American studies programs in universities. However, following the development of universities in African colonies in the 1950s, African scholars became major contributors to African historiography. A notable pioneer is the professor Kenneth Dike, who became chairman of the Committee on African Studies at Harvard in the 1970s. In strict terms Afrocentrism, as a distinct historiography, reached its peak in the 1980s and 1990s. Today it is primarily associated with Cheikh Anta Diop, John Henrik Clarke, Ivan van Sertima and Molefi Kete Asante. Asante, however, describes his theories as Afrocentricity.

Proponents of Afrocentrism support the claim that the contributions of various Black African people have been downplayed or discredited as part of the legacy of colonialism and slavery's pathology of "writing Africans out of history".

Major critics of Afrocentrism include Mary Lefkowitz, who dismiss it as pseudohistory, reactive, and obstinately therapeutic. Others, such as Kwame Anthony Appiah, believe that Afrocentrism defeats its purpose of dismantling unipolar studies of world history by seeking to replace Eurocentricity with an equally ethnocentric and hierarchical curriculum, and negatively essentializes European culture and people of European descent. Clarence E. Walker claims it to be "Eurocentrism in blackface".

Terminology

The term "Afrocentrism" dates to 1962. The adjective "Afrocentric" appears in a typescript proposal for an entry in Encyclopedia Africana, possibly due to W. E. B. Du Bois. The abstract noun "Afrocentricity" dates to the 1970s, and was popularized by Molefi Asante's Afrocentricity: The Theory of Social Change (1980). Molefi Kete Asante's theory, Afrocentricity, has been one developed in academic settings and may incorporate the terms Afrocentric to describe scholarship and Afrocentrists to describe scholars, but does not use Afrocentrism. According to Asante, though the two terms are often confused to mean the same, Afrocentrists are not adherents of Afrocentrism. This has caused confusing notions about who is considered an Afrocentrist, as various scholars who may or may not be associated with Asante and his works have been erroneously given the title, even by other academics. Asante has written that Afrocentricity and Afrocentrism are not the same and neither do they share the same origin:

By way of distinction, Afrocentricity should not be confused with the variant Afrocentrism. The term “Afrocentrism” was first used by the opponents of Afrocentricity who in their zeal saw it as an obverse of Eurocentrism. The adjective “Afrocentric” in the academic literature always referred to “Afrocentricity.” However, the use of “Afrocentrism” reflected a negation of the idea of Afrocentricity as a positive and progressive paradigm. The aim was to assign religious signification to the idea of African centeredness. However, it has come to refer to a broad cultural movement of the late twentieth century that has a set of philosophical, political, and artistic ideas which provides the basis for the musical, sartorial, and aesthetic dimensions of the African personality. On the other hand, Afrocentricity, as I have previously defined it, is a theory of agency, that is, the idea that African people must be viewed and view themselves as agents rather than spectators to historical revolution and change. To this end Afrocentricity seeks to examine every aspect of the subject place of Africans in historical, literary, architectural, ethical, philosophical, economic, and political life.

History

A 1911 copy of the NAACP journal The Crisis depicting "Ra-Maat-Neb, one of the kings of the Upper Nile", a copy of the relief portraying Nebmaatre I on Meroe pyramid 17.

Afrocentrism has its origins in the work of African and African diaspora intellectuals in the late 19th and early 20th centuries, following social changes in the United States and Africa due both to the end of slavery and the decline of colonialism. Following the American Civil War, African Americans in the South gathered together in communities to evade white control, established their own church congregations, and worked hard to gain education. They increasingly took more active public roles despite severe racial discrimination and segregation. American and African intellectuals looked to the African past for a re-evaluation of what its civilizations had achieved and what they meant for contemporary people.

The combination of the European centuries gives us about four to five hundred years of solid European domination of intellectual concepts and philosophical ideas. Africa and Asia were subsumed under various headings of the European hierarchy. If a war between the European powers occurred it was called a World War and the Asians and Africans found their way on the side of one European power or the other. There was this sense of assertiveness about European culture that advanced with Europe's trade, religious, and military forces.

— Molefi Asante, "De-Westernizing Communication: Strategies for Neutralizing Cultural Myths"

As an ideology and political movement, Afrocentrism had its beginnings in activism among black intellectuals, political figures, and historians in the context of the US American civil rights movement. According to U.S. professor Victor Oguejiofor Okafor, concepts of Afrocentricity lie at the core of disciplines such as African American studies. But Wilson J. Moses claims that Afrocentrism roots are not exclusively African:

Despite the fulminations of ethno-chauvinists and other prejudiced persons, it remains a fact that the contributions of white scholars, like Boas, Malinowski, and Herskovits, were fundamental to that complex of ideas that we designate to days as Afrocentrism...Students of African and African American history have long appreciated the irony that much of what we now call Afrocentrism was developed during the 1930s by the Jewish American scholar Melville Herskovits

— Wilson J. Moses, Historical Sketches of Afrocentrism

In 1987, Martin Bernal published his Black Athena, in which he claims that ancient Greece was colonized by northern invaders mixing with a colony established by Phoenicia (modern Lebanon). A major theme of the work is the alleged denial by Western academia of the African and (western) Asiatic influence on ancient Greek culture.

Aspects of Afrocentricity and Afrocentrism

Afrocentricity book

Main article: Afrocentricity (book)

In 2000, African American Studies professor Molefi Kete Asante, gave a lecture entitled "Afrocentricity: Toward a New Understanding of African Thought in this Millennium," in which he presented many of his ideas:

• Africa has been betrayed by international commerce, by missionaries and imams, by the structure of knowledge imposed by the Western world, by its own leaders, and by the ignorance of its own people of its past.
• Philosophy originated in Africa and the first philosophers in the world were Africans.
• Afrocentricity constitutes a new way of examining data, and a novel orientation to data; it carries with it assumptions about the current state of the African world.
• His aim is "to help lay out a plan for the recovery of African place, respectability, accountability, and leadership."
• Afrocentricity can stand its ground among any ideology or religion: Marxism, Islam, Christianity, Buddhism, or Judaism. Your Afrocentricity will emerge in the presence of these other ideologies because it is from you.
• Afrocentrism is the only ideology that can liberate African people.

Asante also stated:

As a cultural configuration, the Afrocentric idea is distinguished by five characteristics:

1. an intense interest in psychological location as determined by symbols, motifs, rituals, and signs.
2. a commitment to finding the subject-place of Africans in any social, political, economic, or religious phenomenon with implications for questions of sex, gender, and class.
3. a defence of African cultural elements as historically valid in the context of art, music, and literature.
4. a celebration of centeredness and agency and a commitment to lexical refinement that eliminates pejoratives about Africans or other people.
5. a powerful imperative from historical sources to revise the collective text of African people.

However, Wilson J. Moses, said of Asante: "His second book, The Afrocentric Idea (1987), was a creative and in some respects brilliant but rambling theoretical work, much influenced by the revolution in "critical theory" that occurred in American intellectual life during the late 1970s and early 1980s." Some also assert that the definition of Afrocentricity has never sat still long enough to be properly described and accurately critiqued.

Afrocentric education

Main article: Afrocentric education

Afrocentric education is education designed to empower peoples of the African diaspora. A central premise behind it is that many Africans have been subjugated by limiting their awareness of themselves and indoctrinating them with ideas that work against them. To control a people's culture is to control their tools of self-determination in relationship to others. Like educational leaders of other cultures, proponents assert that what educates one group of people does not necessarily educate and empower another group–so they assert educational priorities distinctly for the Africans in a given context.

Afrocentric theology

Further information: Black theology and Black church

The black church in the United States developed out of the creolization of African spirituality and European-American Christianity; early members of the churches made certain stories their own. During the antebellum years, the idea of deliverance out of slavery, as in the story of Exodus, was especially important. After Reconstruction and the restoration of white supremacy, their hope was based on deliverance from segregation and other abuses. They found much to respond to in the idea of a personal relationship with Jesus, and shaped their churches by the growth of music and worship styles that related to African as well as European-American traditions.

Twentieth-century "Africentric approaches" to Christian theology and preaching have been more deliberate. Writers and thinkers emphasize "Black presence" in the Christian Bible, including the idea of a "Black Jesus".

Kwanzaa

In 1966 Maulana Karenga of the black separatist US Organization created Kwanzaa; which became the first specifically African American holiday to be widely observed amongst African Americans. Karenga rejected liberation theology and considered the practice of Christianity anti-thetical to the creation of an African-American identity independent from white America. Karenga said his goal was to "give Blacks an alternative to the existing holiday and give Blacks an opportunity to celebrate themselves and history, rather than simply imitate the practice of the dominant society."

Race and Pan-African identity

Further information: Ancient Egyptian race controversy and Pan-Africanism

Many Afrocentrists^[who?] seek to challenge concepts such as white privilege, color-blind perspectives, and race-neutral pedagogies. There are strong ties between Afrocentricity and Critical race theory.

Afrocentrists agree with the current scientific consensus that holds that Africans exhibit a range of types and physical characteristics, and that such elements as wavy hair or aquiline facial features are part of a continuum of African types that do not depend on admixture with Caucasian groups. They cite work by Hiernaux and Hassan that they believe demonstrates that populations could vary based on micro-evolutionary principles (climate adaptation, drift, selection), and that such variations existed in both living and fossil Africans.

Afrocentrists have condemned what they consider to be attempts at dividing African peoples into racial clusters as new versions of discredited theories, such as the Hamitic hypothesis and the Dynastic Race Theory. These theories, they contend, attempted to identify certain African ethnicities, such as Nubians, Ethiopians and Somalis, as "Caucasoid" groups that entered Africa to bring civilization to the natives. They believe that Western academics have traditionally limited the peoples they defined as "Black" Africans to those south of the Sahara, but used broader "Caucasoid" or related categories to classify peoples of Egypt or North Africa. Afrocentrists also believe strongly in the work of certain anthropologists who have suggested that there is little evidence to support that the first North African populations were closely related to "Caucasoids" of Europe and western Asia.

In 1964 Afrocentric scholar Cheikh Anta Diop expressed a belief in such a double standard:

But it is only the most gratuitous theory that considers the Dinka, the Nouer and the Masai, among others, to be Caucasoids. What if an African ethnologist were to persist in recognising as white only the blond, blue-eyed Scandinavians, and systematically refused membership to the remaining Europeans, and Mediterraneans in particular—the French, Italians, Greek, Spanish, and Portuguese? Just as the inhabitants of Scandinavia and the Mediterranean countries must be considered as two extreme poles of the same anthropological reality, so should the Negroes of East and West Africa be considered as the two extremes in the reality of the Negro world. To say that a Shillouk, a Dinka, or a Nouer is a Caucasoid is for an African as devoid of sense and scientific interest as would be, to a European, an attitude that maintained that a Greek or a Latin were not of the same race.

French historian Jean Vercoutter has claimed that archaeological workers routinely classified Negroid remains as Mediterranean, even though they found such remains in substantial numbers with ancient artefacts.

Some Afrocentrists have adopted a pan-Africanist perspective that people of color are all "African people" or "diasporic Africans," citing physical characteristics they exhibit in common with Black Africans. Afrocentric scholar Runoko Rashidi writes that they are all part of the "global African community." Some Afrocentric writers include in the African diaspora the Dravidians of India, "Negritos" of Southeast Asia (Thailand, the Philippines and Malaysia); and the aboriginal peoples of Australia and Melanesia.

Pre-Columbian Africa-Americas theories

Main article: Pre-Columbian Africa-Americas contact theories

In the 1970s, Ivan van Sertima advanced the theory that the complex civilizations of the Americas were the result of trans-oceanic influence from the Egyptians or other African civilizations. Such a claim is his primary thesis in They Came Before Columbus, published in 1978. The few hyper-diffusionist writers seek to establish that the Olmec people, who built the first highly complex civilization in Mesoamerica and are considered by some to be the mother civilization for all other civilizations of Mesoamerica, were deeply influenced by Africans. Van Sertima said that the Olmec civilization was a hybrid one of Africans and Native Americans. His theory of pre-Columbian American-African contact has since met with considerable and detailed opposition by scholars of Mesoamerica. Van Sertima has been accused of "doctoring" and twisting data to fit his conclusions, inventing evidence, and ignoring the work of respected Central and South American scholars to advance his own theory. Mainstream historians of Mesoamerica overwhelmingly reject that view with detailed rebuttals.

Claims have been also forwarded contending that African civilizations were founding influences on the Chinese Xia cultures.

Afrocentrism and Ancient Egypt

Main article: Ancient Egyptian race controversy

Several Afrocentrists have claimed that important cultural characteristics of ancient Egypt were indigenous to Africa and that these features were present in other early African civilizations such as the later Kerma and the Meroitic civilizations of Nubia. Scholars who have held this view include Marcus Garvey, George James, Martin Bernal, Ivan van Sertima, John Henrik Clarke, and Molefi Kete Asante as well as the Afrocentrist writers Cheikh Anta Diop and Chancellor Williams. The claim has also been made by many Afrocentric scholars that the Ancient Egyptians themselves were Black African (sub-saharan African) rather than North African/Maghrebi, and that the various invasions on Egypt resulted in the "Africanity" of Ancient Egypt becoming diluted, resulting in the modern diversity seen today. Examining this view, Egyptologist Stuart Tyson Smith, wrote that "Any characterization of race of the ancient Egyptians depends on modern cultural definitions, not on scientific study. Thus, by modern American standards it is reasonable to characterise the Egyptians as 'black', while acknowledging the scientific evidence for the physical diversity of Africans". Smith, however, expressed criticism of Egyptologists and Afrocentrists that defined ancient Egyptians "as members of an essentialist racial category" with perceived "Caucasoid" or "Negroid/Africoid" phenotypes".

As historian Ronald H. Fritze argued, mainstream Egyptologists and other scholars strongly object to Afrocentric Egyptology, viewing it as "theurapetic mythology" for black people, since it fails to provide sufficient evidence or persuasive interpretations to back up its claims.

Stephen Howe, professor in the history and cultures of colonialism at Bristol University, writes that contrary to "Afrocentric speculation, depending on undocumented assertions that the relatively light-skinned people of the lower Nile today descend from Arab conquerors rather than earlier residents". Howe also cited a 1995 publication which stated "the latest major synthetic work on African populations is firmly of the opinion that "It was not the Arabs physically displaced Egyptians. Instead the Egyptians were transformed by relatively small number of immigrants bringing in new ideas, which, when disseminated, created a wider ethnic identity".

S.O.Y. Keita, a biological anthropologist and research affilitate at the Smithsonian Institution who has been described as sympathetic to Afrocentrism, but defined his position as that "it is not a question of “African” “influence”; Ancient Egypt was organically African. Studying early Egypt in its African context is not “Afrocentric,” but simply correct". Keita has argued that the original inhabitants of the Nile Valley were primarily a variety of indigenous Northeast Africans from the areas of the desiccating Sahara and more southerly areas. He reviewed studies on the biological affinities of the Ancient Egyptian population and described the skeletal morphologies of early dynastic Egyptian remains as a "Saharo-tropical African variant". He also noted that over time gene flow from the Near East and Europe added more genetic variability to the region. In 2022, Keita argued that some genetic studies have a "default racialist or racist approach" and should be interpreted in a framework with other sources of evidence. Several other academics, including Christopher Ehret, Fekri Hassan, Bruce Williams, Frank Yurco, Molefi Kete Asante, Lanny Bell and A.J. Boyce across various disciplines have contended that Ancient Egypt was fundamentally an African civilization, with cultural and biological connections to Egypt's African neighbors.

Scholars have challenged the various assertions of Afrocentrists on the cultural and biological characteristics of Ancient Egyptian civilization and its people. At a UNESCO Symposium in the 1970s, some of the participants, including Jean Vercoutter, Serge Sauneron, Gunnar Säve-Söderbergh and Jean Leclant expressed "profound" disagreement with the "Black", homogeneous hypothesis. Despite contestations, UNESCO decided to include his "Origin of the ancient Egyptians" in the General History of Africa, with an editorial comment mentioning the disagreement. However, Diop's chapter was credited as a "painstakingly researched contribution" in the general conclusion of the symposium report by the International Scientific Committee's Rapporteur, Professor Jean Devisse, which nevertheless lead to a "real lack of balance" in the discussion among participants. The ancient world did not employ racial categories such as "Black" or "White" as they had no conception of "race", but rather labeled groups according to their land of origin and cultural traits. However, Keita studying the controversy, finds simplistic political appellations (in the negative or affirmative) describing ancient populations as "black" or "white" to be inaccurate and instead focuses on the ancestry of ancient Egypt as being a part of the native and diverse biological variation of Africa, which includes a variety of phenotypes and skin gradients.

Egyptian Egyptologist Zahi Hawass has gone on record as saying that the Ancient Egyptians were not black and “We believe that the origin of Ancient Egyptians was purely Egyptian based on the discovery made by British Egyptologist Flinders Petrie at Naqada, and this is why the Ancient Egyptian civilisation did not occur in Africa, it occurred only here”. In 2022, Hawass reiterated his view that "Africans have nothing to do with the pyramids scientifically" and stated that Africans "ruled in Egypt in the late Era, at the time of the 25th dynasty". Hawass also accused some international figures of African descent that promoted Afrocentrism of racism and fabrication of Egyptian history.

In 2008, Stuart Tyson Smith expressed criticism of a facial reconstruction of Tutankhamun as "very light-skinned" which reflected "bias" and "predictably and justifiably, it has provoked protests from Afrocentrists" as "Egyptologists have been strangely reluctant to admit that the ancient Egyptians were rather dark-skinned Africans, especially the farther south one goes".

In 2011, Stephen Quirke, professor of Egyptian Archaeology and Philology argued that the UNESCO-sponsored conference on the General History of Africa in 1974 "did not change the Eurocentric climate of research" and of the need to incorporate both African-centred studies and White European, academic perspectives. He later outlined that "research conferences and publications on the history and language of Kemet [Egypt] remain dominated ... by those brought up and trained in European, not African societies and languages (which include Arabic)".

African-American Afrocentric "hoteps" and the far-right

Main article: Hoteps

African-Americans who use the Black Egyptian hypothesis as a source of black pride have been called "the hoteps" (after the Egyptian word hotep). The term has often been used disparagingly by non-hotep African-Americans, some of whom have linked the ideology of the hotep community – which is anti-feminist, anti-gay and anti-Semitic – to the far-right. Hoteps have been described as promoting false histories and misinformation about black people and black history. Some have argued hotep beliefs are too narrow-minded (focusing only on Egypt as opposed to other aspects of African history), and black feminists argue that hoteps perpetuate rape culture by policing women's sexuality and not criticizing predatory black men.

Alkebulan

Among Afrocentrists the name 'Alkebulan' (also spelled 'Al Kebulan' or 'Alkebu Lan') is sometimes used a replacement for 'Africa.' Users often erroneously claim that it derives from the Arabic for 'Land of the Blacks' (in reality Bilad as-Sudan), or alternatively that it comes from one or more indigenous African languages and means 'Garden of Life' or 'Motherland'. The earliest record of the term 'Alkebulan' is the introduction to an 1813 Spanish poem celebrating the defenders of Zaragoza, in which the author claimed an Arabic origin of the term. In the 20th century it was popularized by Yosef Ben-Jochannan, though this is sometimes incorrectly credited to Cheikh Anta Diop in a non-existent book called “The Kemetic History of Afrika”.

Reception

Afrocentrism has encountered significant opposition from mainstream scholars who charge it with historical inaccuracy, scholarly ineptitude, and racism.

Yaacov Shavit, a critic of the movement, summarises its goals in the preface to his book History in Black, in which he states:

Thus, if historical myths and legends, or an invented history, play such a major role in the founding of every national reconstruction, the question that should concern us here is the nature of the distinct style in which black Americans imagine their past. The answer to this question is that radical Afrocentrism, the subject of this study, which plays a central role in shaping the modern historical world-view of a large section of the African-American (or Afro-American) community, is far more than an effort to follow the line taken by many ethnic groups and nations in modern rewriting, inventing or developing collective identity and national history. Rather, it is a large-scale historical project to rewrite the history of the whole of humankind from an Afrocentric point of view. The result is a new reconstruction of world history: it is a universal history.

Other critics, such as Mary Lefkowitz, contend that the Afrocentric historical approach is entrenched in myth and fantasy. She argues that Afrocentrism is grounded in identity politics and myth rather than sound scholarship. In The Skeptic's Dictionary, philosophy professor Robert Todd Carroll labeled Afrocentrism "pseudohistorical". He argued that Afrocentrism's prime goal was to encourage black nationalism and ethnic pride in order to effectively combat the destructive consequences of cultural and universal racism. Professor of history Clarence E. Walker has described Afrocentrism as "a mythology that is racist, reactionary, essentially therapeutic and is eurocentrism in black face."

Classicist Mary Lefkowitz rejects George James's theories about Egyptian contributions to Greek civilization as being faulty scholarship. She writes that ancient Egyptian texts show little similarity to Greek philosophy. Lefkowitz states that Aristotle could not have stolen his ideas from the great Library at Alexandria as James suggested, because the library was founded after Aristotle's death. On the basis of such errors, Lefkowitz calls Afrocentrism "an excuse to teach myth as history." Mary Lefkowitz in 1997 whilst criticising elements of Afrocentrism had acknowledged that the origins of the ancient Egyptians were more clear due to the "recent evidence on skeletons and DNA [which] suggests that the people who settled in the Nile valley, like all of humankind, came from somewhere south of the Sahara; they were not (as some nineteenth-century scholars had supposed) invaders from the North".

In 2002, Ibrahim Sundiata wrote in the American Historical Review that:

The word "Afrocentric" has been traced by Derrick Alridge to the American historian W.E.B. Du Bois, who employed it in the early 1960s. During the 1970s, Molefi Kete Asante appropriated the term, insisting that he was the only person equipped to define it, and asserting that even the holy archangels Du Bois and Cheikh Anta Diop had an imperfect and immature grasp of a concept that finds ultimate expression in his own pontifications. Subsequently, it became a catchall "floating signifier," nebulous, unstable, and infinitely mutable.

Literature and languages scholar Cain Hope Felder, a supporter of Afrocentric ideas, has warned Afrocentrists to avoid certain pitfalls, including:

• Demonizing categorically all white people, without careful differentiation between persons of goodwill and those who consciously perpetuate racism.
• Adopting multiculturalism as a curricular alternative that eliminates, marginalizes, or vilifies European heritage to the point that Europe epitomizes all the evil in the world.
• Gross over-generalizations and using factually or incorrect material is bad history and bad scholarship.

Nathan Glazer writes that although Afrocentricity can mean many things, the popular press has generally given most attention to its most outlandish theories. Glazer agrees with many of the findings and conclusions presented in Lefkowitz's book Not Out of Africa. Yet he also argues that Afrocentrism often presents legitimate and relevant scholarship. The late Manning Marable was also a critic of Afrocentrism. He wrote:

Populist Afrocentrism was the perfect social theory for the upwardly mobile black petty bourgeoisie. It gave them a sense of ethnic superiority and cultural originality, without requiring the hard, critical study of historical realities. It provided a philosophical blueprint to avoid concrete struggle within the real world.... It was, in short, only the latest theoretical construct of a politics of racial identity, a world-view designed to discuss the world but never really to change it.

Some Afrocentrists agree in rejecting those works which critics have characterized as examples of bad scholarship. Adisa A. Alkebulan states that the work of Afrocentric scholars is not fully appreciated because critics use the claims of "a few non-Afrocentrists" as "an indictment against Afrocentricity."

In 1996, the historian August Meier critically reviewed the new work of Mary Lefkowitz on Afrocentrism as "Eurocentric". He criticized her book Not out of Africa: How Afrocentrism became an Excuse to Teach Myth as History for what he saw as her neglect of the African-American historic literature of the 19th and 20th centuries. Meier believes she fails to take the African-American experiences into account, to the extent that she "fails to answer the question raised in this book's subtitle".

Maghan Keita describes the controversy over Afrocentrism as a cultural war. He believes certain "epistemologies" are warring with each other: the "epistemology of blackness" argues for the "responsibilities and potential of black peoples to function in and contribute to the progress of civilization."