In the introduction to his Bertrand Russell Memorial Lecture in 1972, Noam Chomsky mentioned a Japanese farmer who had a wall poster which read: "Which road is the correct one, which is just? Is it the way of Confucius, of the Buddha, of Jesus Christ, Gandhi, Bertrand Russell? Or the way of Alexander the Great, Genghis Khan, Hitler, Napoleon, President Johnson?" It is doubtful if Russell, a passionate sceptic and libertarian all his life, would have been entirely happy being associated with reactionaries like Confucius, or religious mystics like the Buddha – but nonetheless this poster clearly expresses the false dilemma which we are conventionally presented as soon as we begin to discuss ecology.Murray Bookchin
The last of his kind? Murray Bookchin

Either we have to side with religious mystics and neo-pagans and cultivate a "sacramental" or spiritual attitude towards nature, or to align ourselves with the positivist tradition and mechanistic philosophy, with aggressive imperialism, industrial capitalism and agribusiness. One book by "spiritual ecologist" David Watson, for example, which purports to offer a "deep ecological vision", casts the choice as between either the "prison house of urban industrial civilisation" or "primitivism" – entailing the wholesale rejection of technology, the romanticisation of hunter-gathering tribal life and the embrace of neopaganism. We should reject this false dichotomy.

There is another ecological tradition that repudiates both mechanism and spiritualism, that while critiquing industrial capitalism and the rapacious 'megamachine' does not go to the other extreme and embrace primitivism or some form of religious metaphysic. This is the tradition of organic or ecological humanism, a tradition that is particularly associated with three pioneer social ecologists – Lewis Mumford, René Dubos and Murray Bookchin.

Though, with the death of Bookchin in July, each is now dead, their work continues to provide a vital resource for those concerned with developing a coherent humanist philosophy of how man and nature can and should work together.

These three social ecologists stress that there is an essential paradox at the heart of human life, an inherent duality in social existence. We humans are an intrinsic part of nature, while at the same time, through our conscious experience and our human culture, we are also separate from nature. Mumford speaks of humans as living in "two worlds" - the natural world, and what all three scholars, following Cicero, call 'second nature' - human social and symbolic life which is "within" first nature. Humans, unlike animals, thus have a dual existence, in that they are simultaneously contemplative and active beings, both 'constituting' (giving cultural meaning to) and being actively engaged in the natural world.

Fully embracing Darwin's evolutionary theory, Mumford – a literary and architecture critic – Dubos – a microbiologist – and Bookchin – an anarchist environmentalist – emphasise that humans are a product of natural evolution, and that there is continuity between humans and the natural world, specifically other life-forms. All three scholars thus repudiate Cartesian philosophy, with its dualistic metaphysics - implying a radical dichotomy between humans and nature, the body and the mind - and its atomistic epistemology and anthropocentric ethic, which envisages the technological mastery of nature. Following Darwin, they emphasise that the world – nature – is not a machine but an evolutionary process, which can only be understood by an organic, developmental way of thinking and a holistic (relational) epistemology. This Bookchin describes, betraying the influence of Hegel on his thought, as "dialectical naturalism".

All three scholars stress the crucial importance of historical understanding, especially with regard to biology. Biologist Dubos indeed affirms that nothing in biology makes sense except in the context of history. But they were equally critical of much social science, which divorces culture from nature. Each was a committed evolutionary naturalist.

Though this made them materialists they are critical of all forms of reductive materialism, which tends to downplay the uniqueness of the human species, our "humanness", and they stress in particular the fundamental importance of human culture – technology, the arts, symbolism, philosophy, science – which make humans a unique species. Throughout their writings they make strident criticisms of social Darwinism (the extension of the idea of "survival of the fittest" to social competition between humans) and other forms of biological essentialism which deny the notion of free will, like behaviourism (a form of psychology which tries to explain behaviour scientifically) and sociobiology (which tries to explain all behaviour in terms of evolutionary advantage). They stress that humans do not simply adapt to environmental conditions, but have creative agency. Mumford describes humans as the 'unfinished animal', while Dubos, arguing that humans are dialectically linked to nature, notes that human life tends to 'transcend' its earthly origins. Their humanism involves putting an equal stress on the autonomy and well-being of the human personality, and the development of an ethical naturalism that critiques both cultural relativism and religious absolutism. They aimed for a universal ethics that recognises the sociality and unity of all humankind.

Remaining true to the Enlightenment tradition they therefore emphasise the need to uphold its fundamental values, namely, liberty and the freedom of the individual, equality and social justice, cosmopolitanism and tolerance, and the need to develop a radical form of democracy. They recognise that there is a need to defend this tradition against its neo-romantic detractors.

The key concepts of Mumford, Dubos and Bookchin's evolutionary humanism are wholeness, balance, diversity, autonomy and mutualism. They particularly express the need to sustain both unity and diversity (personal, social and ecological), both human subjectivity and social cooperation, both the flourishing of humans and that of the biosphere, its landscapes and its life-forms.

Reacting against the social Darwinian idea of an inherent biological conflict built in to human life, as well as against the individualism inherent in Cartesian philosophy and mechanistic science, Mumford, Dubos and Bookchin all stress the importance of mutual aid and symbiosis in the understanding of the biosphere, as well as in human social affairs. All three pay tribute to the ecological vision of the Russian anarchist geographer Peter Kropotkin, who introduced the idea that mutual aid could have an evolutionary basis. This meant that they were not only critical of Cartesian dualism but also of the scientistic ethic, most famously developed by Francis Bacon in his De Augmentis Scientiarum of 1623, that views the natural world simply as a human resource and encourages human domination of nature.

Mumford, Dubos and Bookchin, like prominent British humanists such as Julian Huxley, deny that humans can be the 'masters' of nature, and offer powerful critiques of the Baconian 'dream' of mastery. Such a Faustian attitude Dubos argued, was not only misplaced and dangerous, but contrary to biology itself.

Both Mumford and Dubos were in some respects religious thinkers. Dubos is often considered to be an advocate of Christian stewardship regarding nature, though he actually proposed a "scientific theology of the earth". While Mumford did display a vague pantheistic sense of God, it was akin to that of Spinoza, who, as Steven Nadler has argued in these pages, was more concerned with 'naturalising God' than in "deifying nature". But all three social ecologists, when they spoke of 'religion' or 'spirituality', essentially implied a sense of wonder and respect towards natural phenomena, and the need to develop what Bookchin describes as an 'ecological sensibility'. They thus attempt to combine evolutionary naturalism with a form of humanism that is very different from the misanthropic portrait of humans as inherently destructive and predatory animals, and thus in need of salvation or redemption, that is both the staple of the church and is advocated by many contemporary anti-humanist philosophers like David Ehrenfeld (author of The Arrogance of Humanism) and John Gray.

This form of humanism has the following characteristics: it is naturalistic rather than supernaturalist, repudiating spiritualist explanations of natural and social phenomena, thus putting an emphasis on human reason; it affirms the unity of humankind and a naturalistic ethics that recognises the existence of basic universal values; it acknowledges the dignity of the human personality and the crucial importance of upholding such human values as equality, liberty, tolerance and social solidarity; and, finally, it suggests a relational epistemology that emphasises free inquiry, the importance of reason and science, as well as of the human imagination.

What makes the humanism of Mumford, Dubos and Bookchin distinct is that it is combined with a form of Darwinian naturalism. Darwin initiated an intellectual revolution, which introduced the idea that humans are not the special product of God's creation but evolved according to principles that operate throughout the natural world. He stressed the organic (not spiritual) link between humans and nature and undermined completely – long before quantum physics – the mechanistic world-picture, along with its simple dualisms, its cosmic teleology and its essentialism. Natural selection emphasised the crucial importance of openness, chance, probability and the agency and individuality of all organisms in the evolutionary process, and it suggested ways of understanding that were both naturalistic and historical (not static and spiritual).

Mumford described this new synthesis as "organic humanism", Dubos as "ecological humanism", Bookchin as "social ecology". As public intellectuals, Mumford, Dubos and Bookchin, though widely cited in academia, wrote in a popular style, and avoided academic jargon, hoping to reach a wide audience. Although each scholar had a depth of knowledge in specific fields, Mumford in architecture and literature, Dubos in microbiology, and Bookchin in the history of socialism and libertarian movements, all three bewailed the fragmentation of knowledge and the narrow specialisms that characterise contemporary intellectual life. In contrast they adopted a synthetic approach, and in their writings integrated ideas and concepts from philosophy, history, literature, anthropology, psychology, sociology, archaeology and biology. They were radical scholars rather than academics. They felt that an understanding of human social life could only be attained by drawing on a multiplicity of factors – genetic, psychological, historical, environmental. They particularly aimed to bring together and integrate the humanities (philosophy, history) and the social and biological sciences.

Neither Mumford, Dubos or Bookchin doubted the reality of the material world. As Mumford expressed, it only a lunatic would fail to recognise the physical environment, and the need to breathe air, eat food and drink water. They were realists who therefore tended to rail against idealist philosophers like Plato and Kant. But they also stressed, long before postmodernists, that our understanding of the natural world is always mediated, by our own personal experiences, and by social and cultural factors. We thus never see the world through 'pristine eyes'.

As pioneer ecologists, all three offered illuminating accounts of the current ecological crisis. They highlighted the degradation of the natural environment under industrial capitalism - the pollution of the atmosphere and of rivers and lakes; deforestation; the limitations of industrial agriculture and the adverse effects of toxic pesticides and soil erosion; the problems of chemical additives in food; the dangers of nuclear power; and the serious decline in the quality of urban life through over-crowding, pollution, poverty and traffic congestion. Along with the economist Barbara Ward, Dubos drafted the report Only One Earth, which set the agenda for the United Nations Conference on the human environment in 1972, and some 40 years ago both Dubos and Bookchin were highlighting, with some prescience, the dangers of global warming. Long before the anti-globalisation movement, Mumford, Dubos and Bookchin were suggesting that the ecological crisis had its roots in an ever-expanding industrial capitalism, obsessed with economic growth and competition, a market economy that was geared to profits and power rather than human needs. All three were highly critical of the "megamachine" of industrial capitalism and its often unanticipated consequences for the planet.

Mumford and Dubos were essentially radical liberals, while Bookchin was a social anarchist. Nonetheless they tend to agree on the social measures that were necessary to overcome the present crisis. These include the decentralisation of the social economy, and the integration of the city and the countryside to form "bioregional" zones, thus putting an end to the "urbanisation" of the landscape; the establishment of participatory forms of democracy, involving local assemblies and direct democracy; and the scaling down of technology to a 'human scale', through what later became known as 'appropriate technology' (although Bookchin disliked the term, ever vigilant for what he called 'environmentalist hype'). Along with the affirmation of craft industry, all these measures were consistent with the kind of libertarian socialism advocated by 19th century pioneers like William Morris and Patrick Geddes.

But Mumford, Dubos and Bookchin were not neo-romantics; they critically engaged with, and affirmed, the Enlightenment tradition, and were neither anti-technology, anti-city nor anti-science.

Although critical of many aspects of modern science and technology - especially their symbiotic relationship with industrial capitalism - they affirmed the crucial importance of the scientific method and of an ecologically informed technology. Unlike the anarcho-primitivists all three positively affirmed the importance of city life and civilisation. In contrast to 'deep ecologists' and eco-philosophers who make a fetish out of the wilderness, Mumford, Dubos and Bookchin emphasise the positive and creative aspects of humanity and the importance of humanised or cultural landscapes – which actually constitute the living environment of most humans. What they always insisted upon was the need for diversity, and thus the need to develop and conserve wilderness areas (natural landscapes), the countryside (cultured landscapes such as woods, parks, meadows, gardens and cultivated fields) and urban settings, the town or city duly scaled to human needs and human wellbeing.

Given their ecological vision, Mumford, Dubos and Bookchin always stressed that humans were an integral part of nature, and that the relationship between humans and nature should not be one of mastery of dominion, but rather one that was cooperative and symbiotic. In Bookchin's words, dialectical.

Providing a way to link a humanist philosophy - shorn of it's arrogant anthropocentrism – with a sense of the value of nature and natural processes, the social ecology developed by Mumford, Dubos and Bookchin, continues to supply the vital philosophical underpinning to any attempt to use human ingenuity to prevent human self-destruction. From climate change to genetic modification, alternative energy sources to population growth, such a philosophy is today more relevant than ever.

Brian Morris is Professor Emeritus in Anthropology at Goldsmith's College