Darwinian Historical Materialism and Human History: An Outline
A Darwinian Theory of History
In outlining a Darwinian historical materialism I would begin by emphasizing the long-term rises in levels of production, of population, and of military power that have occurred, to varying degrees, not only in Eurasia but in most habitable regions. These fundamental historical trends clearly need to be explained and, if possible, subsumed under a general explanatory scheme.[1]
Explanations of this sort presuppose, of course, that enough people know which are the better techniques and the appropriate organizational forms. But the absence, or undeveloped state, of the natural and social sciences throughout most of human history leads me to think that such a presupposition is unwarranted. Even if people wanted to achieve some form of ‘adaptation’, and they had the social power necessary to do so, there seems to be no reason to think that they were standardly knowledgeable or rational enough to know which traits were more adaptive.[2]
Moreover, although human behaviour is undoubtedly intentional (and even occasionally rational), both intra- and inter-societal conflict and compromises give rise to too many unpredictable and unintended consequences to allow us to see rational choice as the unmediated basis for the long-term trends that occur in human history.
(In arguing that a rational choice mechanism is implausible, I should emphasize that I am not advocating a simplistic form of determinism. I have no need to deny that human action is intentional, or that people (or at least the more powerful) are more or less free to choose productive techniques, social relations, cultural practices and values, and so on. People are not, however, free to choose the consequences of those choices beyond the most immediate. So (to anticipate a point made in the sketch of human history below), in circumstances in which a shift towards cultivation would enhance their productivity (and therefore their reproductive fitness and military power), hunter-gatherers can certainly choose not to make such a shift. But they cannot decide that such a choice will have no adverse consequences for themselves if other groups decide to adopt elements of cultivation (thereby happening to enhance their reproductive fitness and military power). To extend a thought of Marx’s: people make history, but not in circumstances that they please or that they fully understand, and nor, therefore, with the results that they please.)
It is more plausible to assume that cultural innovations are effectively ‘random’ with respect to the long-term trends adverted to above (much as, in natural selection, genetic variations are regarded as ‘random’ with respect to their effect on reproductive success). Such random innovations, however, would clearly not issue in those long-term directional trends unless they were subject to some kind of selection process, perhaps one akin to natural selection.
The central claim of the theory of natural selection is that, within organic populations, differential reproductive success leads to the spread of those inherited variations that enhance (relative) reproductive success.[3] Within these populations, consequently, there are tendencies towards increasing reproductive success and, therefore, accelerating population growth. Whether these tendencies are realized as long-term trends depends upon, among other things, the extent to which a population can continue to extract resources from its environment, given that resources are always limited and that there is usually competition from other organisms.
I would argue, somewhat analogously, that within human populations differential reproductive and/or military success lead to the expansion of the groups possessing those (behaviourally-transmitted) cultural variations that most enhance reproductive and/or military success respectively (often at the expense of those groups that do not possess the cultural variations that enhance reproductive and/or military success), and therefore lead to the spread of those cultural variations.[4] Consequently, there will be persistent tendencies within human populations to increasing reproductive success (and accelerating population growth) and increasing military power. These tendencies seem to have been realized, given the trends of rising levels of population and military power across most of human history that I referred to in the first paragraph above.
(To return, briefly, to the issued of rational choice explanations. Suppose, highly unrealistically, that cultural innovations were largely selected on the basis of reasonably well-informed and more or less rational choices, and with the purpose of enhancing reproductive and/or military success. The result would probably strengthen tendencies to rising levels of reproductive fitness and military power, and perhaps operate somewhat more rapidly than a process of entirely random choices plus ‘blind’ selection. But even in this unlikely scenario, groups would still vary, and differential reproductive and/or military success would still operate to select between groups, further strengthening these ‘adaptive’ tendencies.)
The facts of population and species extinction should make it clear, of course, that the operation of natural selection does not always lead to a rise in fitness for a population or a species. Both natural selection and Darwinian historical materialism say that traits that enhance reproductive success tend to spread. But for neither theory does this preclude the decline and even extinction of groups or populations, or even species. Both animal and human populations live in finite and changing natural environments, and (changing) environmental conditions can lead to population decline and even extinction. Moreover, both animal and human populations are subject to competition (especially from conspecifics). For human societies, as Darwinian historical materialism emphasizes, this competition can involve organized warfare, the destruction of societies, and the displacement of populations.
However, the evidence of long-term trends of rising population levels for the human species as a whole (as opposed to declining levels for some groups or populations) leads me to think that occurrences of stagnant or declining ‘fitness’ in human history (for reasons other than the reproductive and/or military competition from other groups or populations that the theory postulates) have been less significant historically than the overall trend of rising population. (And, to anticipate the argument of the following section, rising levels of production per capita over the very long term would also support the claim that rising levels of ‘fitness’ have been more common historically than periods of stagnant or declining ‘fitness’.)
Darwinian Historical Materialism
So, differential reproductive and/or military success lead to the spread of those behaviourally-transmitted cultural variations that enhance reproductive and/or military success respectively. But there is a missing element within this Darwinian approach to human history, the addition of which will enable us to establish the connection with historical materialism.
It is helpful here to continue to think in terms of an analogy with natural selection. I have said that natural selection claims that differential reproductive success leads to the spread of those inherited variations that enhance reproductive success. But what is it that explains which variations, in particular cases, will most enhance reproductive success (and that therefore explains which variations will tend to spread through differential reproductive success)? The standard answer, I would suggest, is that it is the population’s relationship to its environment that explains which variations will most enhance reproductive success (and how organisms extract resources from their environment might be the most important element of that population-environment relationship). So, for example, whether there is selection for greater speed or greater strength in a population of predators depends upon the predators’ methods of predation and the (evolving) nature of the species that they prey upon.
We can ask an analogous question of this Darwinian approach to history. Differential reproductive and/or military success, I have said, lead to the spread of those cultural variations that enhance reproductive and/or military success respectively. But what is it that explains which variations, in particular cases, will most enhance reproductive and/or military success (and that therefore explains which variations will tend to spread because of differential reproductive and/or military success)? The answer suggested by the analogy with natural selection is that it is the human population’s relationship to its environment that plays this explanatory role.
So, to reconstruct the preceding argument in three premises and a conclusion:
- Characteristics of production largely explain which available cultural variations will most enhance production.
- Cultural variations that enhance production will tend thereby to enhance reproductive and/or military success (given that variations in levels of production largely explain variations in reproductive and military success).
- Cultural variations that enhance reproductive and/or military success will tend to spread within populations.
- Characteristics of production, therefore, explain which cultural variations will tend to spread within populations.
(Something like this theory is, I think, implicit in Jared Diamond’s Guns, Germs and Steel. It also seems to me that many of the explanations that Ian Morris offers for historical change in Why the West Rules – For Now are compatible with the theory.)
All of the above, of course, assumes that the relevant cultural traits are behaviourally transmitted from generation to generation largely within groups, and that there is a sufficient supply of cultural innovation to provide the necessary between-group cultural variation. In their different ways, most, if not all, historians and social scientists implicitly accept these assumptions.[5]
Some Clarifications
Given this central explanatory role of production, it follows that the outcomes of the above processes in different regions will depend upon the characteristics of production in those regions (including productively-relevant characteristics of geography, climate, ecology, and so on). We should expect different outcomes, consequently, in such differentially resourced regions as Eurasia/North Africa, the Americas, sub-Saharan Africa, and Australia
(It should, however, be borne in mind that, in developing their productive techniques, human populations and groups not only transform their environments, but thereby transform their relationships to those environments in the process, transforming the productively-relevant circumstances, and therefore the constraints and opportunities of the selective processes in which they are involved.)
Reproductive ‘competition’ and military conflict lead, then, to the expansion of the more productive societies, and thus a long-term tendency to productive development. But it is characteristics of production in particular circumstances that explain which changes in productive practices will enhance levels of production (and thus reproductive and/or military success). Characteristics of production in particular times and places explain, for example, whether shifting away from hunting-gathering and towards horticulture and/or herding will enhance production (and therefore reproductive and/or military success). And the characteristics of production in different regions will also determine to what extent intensifying agricultural production would be productively advantageous (and thus reproductively and/or militarily advantageous). It is their differing productive potentials, therefore, that explain why regions will tend to vary in their rate of productive development.
It is also characteristics of production that explain the development of new social forms. In regions where production could develop relatively rapidly (in the temperate, Mediterranean, and sub-tropical climatic zones of Eurasia, for instance), the development and spread of new social forms that enhanced production also occurred relatively rapidly. Where production could only develop relatively slowly (in the pre-Columbian Americas, for instance), then the development and spread of new production-enhancing social forms occurred relatively slowly. In regions where there could be relatively little indigenous productive development (in Aboriginal Australia, for instance), then relatively little production-enhancing social change occurred. In all of these regions, differential reproductive and military success sifted random cultural variations, selecting those that enhanced levels of production, but the long-term outcomes were different in each region because the possibilities of indigenous productive development were different in each region.
Moreover, although military conflict (along with reproductive ‘competition’) leads to the expansion of the more productive societies, and thus a long-term tendency to productive development, it is differences in forms of production that explain differences in forms of military conflict. Thus, the development of production over the millennia, from hunting-gathering to horticulture-herding to intensive agriculture to industrial production, although partly selected for by warfare, explains changes in the form of warfare.
For example, in circumstances in which immensely destructive ‘defensive’ battlefield weapons began to be mass produced, close-order tactics would no longer be optimal in warfare, and those armies that replaced them with more flexible battlefield tactics would tend, other things being equal, to be more successful. So changes in production explain (through the mechanism of differential military success) the change from close-order to more flexible tactics.
Warfare itself may also tend to select for larger societies with denser populations, societies that can field larger armies during military conflicts. But the size of societies that is actually selected for by warfare is largely explained by facts about production in those societies: the more developed the productive technology (including the technologies of transportation and communication), the larger the society and the denser the population, and therefore the larger the army that can actually be sustained during conflicts. So it is productive development that primarily explains the increasing size of societies and armies over the long term. (In periods of productive decline, conversely, there will be selection against larger societies, and against their larger armies, when the level of production can no longer sustain the population densities, and the divisions of labour and of social roles, that larger societies involve.)
So, production, reproduction and warfare together explain historical change, but they play different roles in that explanation. Historical change is ‘driven’ by random cultural innovations (in productive techniques, social relations, and cultural practices and values). Differential reproductive and/or military success, however, ‘winnow’ those random cultural innovations, and this leads to the spread of those cultural variations that enhance reproduction and/or military success respectively in particular areas and at particular times. They do this largely through enhancing production - but they can only do so at the rate, in the direction, and to the extent that is allowed by the different possibilities of productive development at the particular places and times. Combining this explanatory role of production with these ‘mechanisms’ of differential reproductive and/or military success justifies designating this approach to history as a Darwinian historical materialism.
It would clearly be a mistake to think that this model of history is obviously true. But it would also be a mistake to think it is obviously false. I would suggest that the historical evidence, at least over the very long term, provides significant support for the theory. Despite (sometimes prolonged) episodes of declining levels of production, population and military power, the tendencies that the theory posits certainly seem to have been realized as long-term trends. But let us sketch how this approach would begin to explain some of the major transitions that have occurred in human history.
A Sketch of Human History
The development and spread of farming-herding
Humans spread within and beyond Africa while still living as hunter-gatherers. Those hunting-gathering groups that, in the particular circumstances faced by their wider populations, tended to be the reproductively (and perhaps militarily) most successful - usually the most productive within the prevailing circumstances - would have expanded more rapidly and populated more of the world, carrying their productively (and therefore reproductively and, perhaps, militarily) successful cultural traits with them.
There would, of course, always have been significant variation between hunting-gathering groups, and they would have responded to any environmental changes in a variety of ways. While remaining hunter-gatherers, some groups would have been just a little further than others along that complex continuum between complete reliance upon hunting and gathering and (almost) complete reliance upon farming and herding (perhaps practising a little weeding and watering of favoured stands of wild plants, or sometimes driving and penning wild animals for later consumption rather than simply beating them towards waiting hunters).
The very slow transition to farming and herding began when and where productively-relevant circumstances changed such that the level of production of the hunter-gatherers who happened, say, to practise a little weeding/watering and/or driving/penning was higher than the level of production of those hunter-gatherers that did not do those things. The enhanced levels of production achieved by the former would have allowed enhanced levels of reproductive and/or military success (at the expense of the latter). Greater reliance upon increasingly cultivated, and then domesticated, foods therefore spread through the wider population, and complete reliance upon purely wild foods declined.
The end of the last Ice Age around fifteen thousand years ago, when the climate became warmer and wetter and ecosystems became richer and more diverse, was almost certainly a crucial change that shifted the balance of costs and benefits away from foraging and towards a transition to cultivation and then domestication. The productive techniques of hunter-gatherers in some regions may also have developed to a level that favoured the transition (with, for example, the development of more sophisticated plant-processing tools). Resource stress, perhaps due to population pressure, may also have played a part. In some parts of the world, the decline of the Pleistocene megafauna, perhaps in part because of the effects of human predation, may have been significant in shifting the balance of costs and benefits away from hunting. Crucially, although the balance of costs and benefits was shifting, it would have done so at different rates in different regions. So domestications seems to have developed first in those regions with particularly dense concentrations of potential domesticates: in Southwest Asia during the eighth millennium BCE, in East Asia and South Asia in the sixth millennium BCE, in Mesoamerica in the late fourth millennium BCE, and in the Peruvian Andes in the early third millennium BCE.
Farming-herding thus developed and spread at the expense of hunting-gathering. As this process continued over millennia, the average human group became less and less reliant upon hunting-gathering, and more and more reliant upon farming and/or herding. Populations increased, societies expanded, and military power grew. (In some regions, such as the Americas, a lack of domesticable animals may have prevented the development of herding. It may also have prolonged the benefits of hunting and slowed the shift to permanent sedentism.)
(If a shift to farming and/or herding had not led, in the prevailing productive circumstances, to higher levels of production than hunting-gathering, and therefore to higher levels of reproductive and/or military success, then there would seem to have been no reason why farming-herding would have spread at the expense of hunting-gathering.)
It should be emphasized that, in those regions where independent transitions from hunting-gathering to farming-herding occurred, the transition itself would have had to enhance reproductive and/or military success. There may have been areas, therefore, where an independent transition might not have occurred because such a transition would not have enhanced levels of production, either because hunting-gathering was particularly productive (such as in riverine and coastal areas) or because proto-horticulture would have been particularly unproductive (such as in more arid regions). The spread of farming-herding to these areas may have occurred only when farming-herding had developed in adjacent regions to the point where it enhanced production more than hunting-gathering in those particular environments.
So changes in production, perhaps largely deriving from changes in the productively-relevant aspects of the environment, explain the shift from differential reproduction and/or warfare selecting relatively small, mobile, foraging societies to differential reproduction and/or warfare selecting semi-sedentary forager-cultivators, and then to differential reproduction and/or warfare selecting sedentary, agricultural societies. The transition, of course, would have varied depending upon the particular productive circumstances within which it was taking place.
As they made the long transition from hunting-gathering to farming-herding, people may have worked harder, had poorer diets, perhaps even shorter lives. But history, at least until the demographic transition, seems to have been more about increasing the quantity of people than improving the quality of their lives.
The development and spread of hierarchies, chiefdoms and states
As the regions dominated by farming (and sometimes herding) expanded, further productive development and social changes occurred within those regions.
Simple farming societies, like simple hunter-gatherers, were relatively egalitarian (at least within, if not between, genders), with economic structures characterised by reciprocal exchange and occasional redistribution. But where levels of production could be raised through intensifying production by getting people to work harder, those groups that did work harder would enhance their level of production, and could therefore enhance their reproductive and/or military success. One common social mechanism by which this was achieved seems to have been that more assertive men (and there are always more and less assertive men) could gain status by encouraging, and perhaps cajoling, people to work harder. In such circumstances, groups that were less resistant to such assertive ‘big men’ could thereby enhance their reproductive and/or military success relative to those groups that were more resistant to such men. (These ‘big men’ might also have tended to be more effective leaders in warfare.) So the less-egalitarian groups expanded at the expense of the more-egalitarian groups (which either increased their own levels of production by becoming more hierarchical, or were displaced by more hierarchical groups).
To the extent that production could continue to be developed in this way, societies generally became less and less egalitarian and more and more hierarchical, with economic structures shifting from egalitarian reciprocity to stratified redistribution. Higher status ‘big men’ (and their followers) could develop, over centuries or millennia, into less productive chiefs (and their entourages) and finally into entirely non-productive ruling elites of state-level societies, gaining more status, and eventually power and wealth, by encouraging, then cajoling, intimidating, and eventually coercing people into working harder.
In general, hunting-gathering modes of production are not very intensifiable because they are so dependent upon the natural reproductive rate of wild plants and animals. Levels of hierarchy among hunter-gatherers, consequently, were relatively limited. They perhaps reached the level of proto-chiefdoms in some particularly productive environments, such as along rivers and seacoasts (some sedentary, food-storing hunter-gatherers of the Northwest Coast of North America, for instance, may have developed into proto-chiefdoms as far back as the second millennium BCE).
Farming-herding modes of production can, through higher work rates (involving more frequent planting and weeding, fertilizing, ploughing, forest clearance, irrigation, terracing, shepherding, selective breeding, and so on), generally raise the reproductive rate of plants and animals more than can hunting-gathering modes of production. Consequently, levels of hierarchy were much less limited among many farming-herding societies than among hunter-gatherers. Some farming-herding societies that could only intensify production to a small extent survived into the ethnographic present as ‘big men’ societies (as in Melanesia or New Guinea) or perhaps chiefdoms (as among the Trobriand Islanders of the western Pacific). But within those farming-herding regions where it was possible to highly intensify production, state-level societies developed and spread through demographic and/or military pressure (often at the expense of less productively developed chiefdoms). Thus the regions of independent state formation seem to have been particularly fertile zones, either river valleys (Mesopotamia, Egypt, the Indus Valley, the Yellow River Valley, and Peru) or lake systems (the Mesoamerican highlands). Centralised states developed in each of these regions around three to four millennia after the development of domestication.
The subjugation of the direct producers was essential for the development of states. However difficult this process, those that best achieved it were able to channel increasing resources into more population growth and rising military power, and thus expand. Significantly, these fertile zones within which states first developed seem to have been surrounded by very arid zones, or even deserts, with much less agricultural potential. So any direct producers that attempted to escape increasing subjugation would have been faced with significantly lower levels of production, and of reproductive and/or military success.
So, more hierarchical societies (chiefdoms, and ultimately states) developed and expanded at the expense of less hierarchical societies when, where and because more hierarchical societies could increase levels of production (and therefore increase levels of reproductive fitness and/or military power) more effectively than less hierarchical societies.
(If more-hierarchical societies had not, in the prevailing productive circumstances, achieved higher levels of production than less-hierarchical societies, and therefore higher levels of reproductive and/or military success, then there would seem to have been no reason why more-hierarchical societies would have spread at the expense of less-hierarchical societies.)
The development and spread of capitalism
Conclusion
I should also stress that I am not trying to explain everything about human history; I am merely trying to explain as much as possible with as few assumptions as possible. Evolutionary biologists often emphasise 'feeding, fornicating and fighting' (in their more polite moments) as the crucial elements to focus on in explaining animal behaviour. And some economic historians focus on 'power and plenty' (to which I would add 'procreation') in their accounts of international competition in the 'age of mercantilism'. I am arguing, similarly, that an understanding of the processes of production, reproduction and warfare, of the interrelationships between them, of the persistent tendencies they give rise to, and of the implications of this for other cultural traits, can significantly improve our understanding of human history
[2] ‘Adaptive’ traits, in this context, are those traits that would raise levels of production, reproductive success, or military power, because it is directional trends in these that we are trying to explain.
[3] For the sake of simplicity, I have subsumed differential survival under differential reproductive success. Strictly speaking, a selection process can occur through differential survival or through differential reproduction, or through both. A trait can spread if it increases the probability of survival of its carriers even if it does not increase (and even decreases, to a lesser degree) their probable reproductive success. Conversely, a trait can spread if it increases the probable reproductive success of its carriers even if it does not increase (and even decreases, to a lesser degree) their probability of survival. I think it best, at this stage of conceptual development, to ignore this complication.
[4] Higher reproductive success can, of course, contribute to greater military success – and vice versa – but they are not necessarily connected, and can occur independently of each other.
[5] The above formulations raise an obvious problem for this approach to history in that they seem to involve a form of group selection, and group selection is, of course, controversial. For some thoughts on this issue, see ‘Darwinian historical materialism and group selection’ in the Considerations section of this website.