This interview brings together Dave Murphy, an energy transition scholar, and physicist Tom Murphy, both founders of the Planetary Limits Academic Network (PLAN).
Across this series of discussions conducted by fellow founder Ben McCall, they explore a range of themes on the converging crises reshaping our world, including the polycrisis, ecological overshoot and the strengths and limits of modernity.
Read the whole series: Part One | Part Two | Part Three | Part Four
Ben: Tom, how should we pursue the sustainable option? Is there another choice besides the route Dave has proposed?
Tom: First, I want to point out that my quote was “rethink or abandon” human cultural constructs. The rethink part comes first, and certainly allows selecting and amplifying positive cultural qualities accumulated by various cultures over time. Culture is a non-genetic set of principles that we use to shape how we live. Humans will never be without culture, but some are more sustainable (valuable) than others.
Second, evaluating sustainability on evolutionary timescales does not mean we have the luxury of similarly long timescales to change our ways. Ample evidence shows that we can cause enormous ecological damage on much faster timescales (decades)—thus our predicament. We would be wise to reverse course just as quickly. A fundamental asymmetry operates here: sustainability needs to be assessed over very long timescales, while unsustainability—modernity’s bailiwick—can be arbitrarily fast. Full-scale nuclear war illustrates this principle in the extreme: many millions of years of evolution wiped out in moments.
The path Dave illustrates has nice features, but does not address ecological sustainability on relevant timescales. Even with zero GHG emissions, raising poorer populations to average global standards, stabilizing and feeding a population of 8 billion without fossil fuels, and maintaining current physical output (ending growth), how could Earth pay its annual salary (of non-renewable demands and waste streams) for very long out of the finite environmental inheritance?
Those lifted out of poverty would finally be able to afford more material goods (possibly a car or a house), eat more and better food, enjoy climate control, etc. I am not saying that I would not wish such things, but they all act to increase the scale of the human enterprise. The only “bank” available to fund this “pay raise” is our overtaxed Earth, in the form of more non-renewable materials (mining), more manufacturing (pollution), more land use (deforestation, soil erosion, runoff, aquifer depletion), and more energy (materials and manufacturing again). Now we try to lock in this higher demand for the long haul (steady “burn” rate)? We appear to be well into overshoot, so neither an increase nor holding steady seems possible. Even redistribution that equalizes all to the current global average does not reduce the absolute scale. The ecological nosedive is so rapid that maintaining a scale even resembling that of modernity will most likely finish the job, whatever the technology.
My point is that we need to be extremely careful to assess what can work for the long term, rather than aim for a pleasant near-term extrapolation of the familiar that only continues to degrade ecological health and is not based on a realistic evaluation of long-term sustainability in its full context.
Do we have another choice? Of course! We could become disenchanted with modernity as an unfortunate dead end and explore other ways of living and relating to the world. It can’t happen overnight, but we are under no obligation to follow a “modernity lite” path to failure. Attempting to do so could ultimately make life worse for more people and animals.
Ben: Dave, it seems that Tom is suggesting that your proposal (clean energy transition, lifting people out of poverty, and the like) is not sustainable and would indeed position us for increasing ecological devastation in the coming decades. He instead seems to suggest that the only way to achieve sustainability is through a radical rethinking of our relationship to the natural world, presumably with correspondingly radical changes in our energy and material throughputs. I know you’re a proponent of the precautionary principle…so why shouldn’t your proposal be viewed as too risky, given the stakes involved?
Dave: Thanks for clarifying your points on culture! I agree that there is a lot to be gained from humanity’s accumulated history!
I also agree, and it is a very good point that unsustainability can occur on very fast time lines, while the assessment of sustainability should be over longer time scales. That said, couldn’t an “act of unsustainability” in one time period be compensated for by “acts of sustainability” later on, as long as permanent change hasn’t occurred?
To the larger issue, while trying to get to the bottom of our differences, clarifying what is meant by modernity, sustainability, timescales, etc, it is becoming clearer to me through these exchanges that Tom has made an a priori assumption about the future, which he stated in his last post: “The ecological nosedive is so rapid that maintaining a scale even resembling that of modernity will most likely finish the job, whatever the technology.” Of course, since the future hasn’t happened yet, we cannot prove or disprove this assumption, relegating it to a form of metaphysics, or a belief system, or, as Joseph Schumpeter called it, a “preanalytic vision.”
The preanalytic vision, developed by Schumpeter, is defined by economists Herman E. Daly and Joshua Farley: “analytic effort is of necessity preceded by a preanalytic cognitive act that supplies the raw material for the analytical effort.” Importantly, Daly and Farley describe that,
“One might say that vision [i.e. pre-analytic vision] is the pattern or shape of the reality in question that the right hemisphere of the brain abstracts from experience, and then sends to the left hemisphere for analysis. Whatever is omitted from the preanalytic vision cannot be recaptured by subsequent analysis. Correcting the vision requires a new preanalytic cognitive act, not further analysis of the old vision.”
It seems to me that Tom’s analytic effort – which is on display – was preceded by his vision that “maintaining a scale even resembling that of modernity will most likely finish the job.” My vision–one in which we make incremental (hopefully large) gains over the next few decades, becoming more sustainable through time and level out population growth through the demographic transition – is an impossibility to Tom, not because it is wrong or incorrect, but rather it is impossible simply because it is omitted from Tom’s preanalytic vision. Thus, further discussion will, I fear, remain futile.
In many ways, what Tom is calling for is a paradigm shift towards collapsism, much as ecological economics calls for a paradigm shift away from neoclassical theory. For ecological economists, the idea that society could have a steady-state economy (i.e. more or less what I am calling for) was (and is) inconceivable for neoclassical economists because the idea of a steady-state economy was omitted from the growth-based models on which neoclassical economics was built. In other words, steady-state economics is impossible in a neoclassical vision of the economy, just the same way that steady-state economics is impossible in a collapsist vision of the future.
I would also like to say that collapse is still possible in the spectrum of futures in my vision, it is just one I hope doesn’t happen. So in this way, Tom’s vision is more restrictive than mine. I do not require a paradigm shift to see that collapse could happen, but I also do not need one to see sustainability happen.
But I would like to bring this conversation back to ethics at this point, because that is where I get stuck. What happens to people in Tom’s radical reboot of human culture on Earth? The implication (though never stated explicitly) is that sustainability is only possible in Tom’s vision if there are way fewer people. Is that correct? If so, how do we get there? Do we just accept that many millions (if not billions) of people must cease to exist to be sustainable? How do we approach that subject?
I said in the beginning that I am optimistic because I have children. My kids are my joy in life, and it seems not only against our basic biology but also ethically dubious to try to tell people how many children they can or cannot have; in other words, policy solutions limiting children are not an option. So how do we do it? War, famine? My guess is that Tom’s response will be that it is out of his hands, but suggesting that only one future is possible, and that that future must also have many millions (billions?) fewer people in it, requires at least addressing the pathway to achieving that. And that is where the ethics come into play. Who are we to assess which people around the world, which generations (today or future), are more or less important? Everyone is equally important and deserves life. So, I think we really don’t have any choice; we are required to, as Tom put it, “do our best.” Yes, we have grown to a size that is problematic right now, but that doesn’t mean it has to be in the future. How are you going to “do your best?” How will any of us do our best? For my part, I will raise my kids to be environmentalists, feminists, and change-makers, instilling in them (as best I can) virtues and ethics. I will also produce as much good science as I can and never succumb to nihilism or defeatism, no matter how bad the global environmental, political, social, or economic situation gets.
To be clear, I don’t disagree that population is a driving factor in environmental degradation. It clearly is. For me, the demographic transition is the only way to reduce growth equitably (and probably ethically), and it has shown itself time and time again to work. It doesn’t require endless economic growth, rather (among other things) gender equity and poverty reduction are required, both laudable goals by themselves.
Ben: Tom, is the difference between your vision of the future and Dave’s indeed a metaphysical one? Or can you make an argument that Dave’s vision is indeed “wrong or incorrect”?
Tom: Dave raises a good point about pre-analytic vision. And it remains true that we cannot know the future. I have arrived where I am via a combination of data, extrapolation, fundamental drivers, and the precautionary principle.
I do not believe I exclude steady-state-modernity notions because my biases have precluded me from considering that state: I was once a big fan! My objection concerns continued reliance on non-renewable materials (as quantified by recycling longevity) and ongoing ecological harm—whose prevention/reversal is effectively omitted from “transition” pre-analytics. Extinctions and non-renewable resource depletion are permanent costs that I would rather not keep racking up steadily.
I would not call our difference metaphysical so much as contextual. No matter what each of us considers in our metaphysical framework, Earth is suffering irreversible losses at a rate not seen since the Chicxulub impact 65 million years ago—a condition that is not subject to our preferred cosmologies. But speaking to metaphysical differences, my foundation is that we belong to the world, rather than it to us. Maybe that core tenet makes my positions seem alien, shaping my values and what I consider important.
While I am a big fan of acknowledging the tennis match between right and left hemispheres, the exercise can be a long volley that spans decades and allows numerous corrections. This allows the pre-analytic vision to adapt and re-form based on analysis: rinse and repeat. If I look at my writings from a decade ago, my metaphysical (pre-analytic) realm was missing many pieces that I now possess, informed by analytic exercises and wrestling with their ramifications.
Among these, and germane to the present discussion, I recognize that just because the demographic transition repeatedly “worked” for the Western world in the past (ask critters how well it worked) does not mean it will work similarly for today’s poorer countries. The context has changed dramatically. 70 years ago, the world had a third as many people, a fossil fuel glut ahead of it, and a bounty of low-hanging fruit (materials) and unexploited ecosystems around the globe. A demographic transition: 1) takes many decades; 2) has always involved a significant population surge, as death rates fall well before birth rates; 3) results in greater affluence (per capita resource demand); so that 4) the aggregate resource burden on the planet soars from the combined effect. Earth had the (non-renewable) cash on hand 70 years ago, but can no longer afford rinse-and-repeat. This is a case of analysis reshaping pre-analytic vision.
Similarly, my statement about the ecological nosedive is not a starting point for me but a relatively new awareness based on data and analysis. In 2023, I produced a plot of wild land mammal mass per human on the planet, over time. The result is startling. It changed me. It was not part of my pre-analytic metaphysics before performing the analysis, but it will be going forward. As mentioned previously, only 2.5 kg of wild land mammal mass exists per person on the planet: it’s almost gone. In 1800, it weighed 80 kg and was already beginning to fall rapidly. This has happened not because of CO2, but due to deforestation, resource extraction and its associated ills, habitat fragmentation, overhunting, extermination, pollution, invasives, human-borne disease, and displacement by the human enterprise (i.e., modernity). Climate change interacts with these things to make a dire situation even worse.
Given the accelerating pace of wild population declines, I am left to ask: What action could possibly stabilize them or cause them to start rising again? The phenomenon is so steep, it would take an enormous, concerted effort to arrest the fall, and that won’t happen by accident as an unintended byproduct of demographic or renewable energy transitions. In fact, those things would appear to dial up pressures on the ecosystem via resource extraction—not to mention all the things we elect to do with the energy (hint: ecological restoration is not high on the list).
The sixth mass extinction appears to be underway now, and it’s happening fast. I would feel much better about modernity’s transition ambitions if the ecological crisis were modernity’s primary concern, but it takes a back seat to satisfying short-term human demands in a state of overshoot. To be clear, I am not defeatist or nihilistic about this: I am agitating hard to do something different—to get people to think differently—hoping we can avoid the worst unforced errors. I’d rather we collectively not have to see it to believe it.
As for ethics, I will just say that the scope must extend beyond humans alone, and well beyond the present century. My own “who are we” question is: who are we to consign entire species to the dustbin—avoidably? If satisfying the short-term wish list of one culture (that of modernity) extinguishes several species per day, I don’t know how to ethically justify those priorities. More maddeningly, doing so runs a sharp risk of promoting our ultimate failure, as we—especially modernity—will struggle amid the ensuing ecological collapse. I see the situation as simply unfortunate. We find ourselves holding the wolf by the ear: we can neither let go nor hold on indefinitely without suffering harm. We don’t have the luxury of stipulating that present-day humans suffer no downside. In fact, it is not unreasonable to expect the downside to be proportional to the magnitude of our current transgression against sustainability. Fairness will not always appear to operate in our favor.
Ben: To bring this conversation to a close, I’d like to note that this wide-ranging discussion has laid bare a number of important disconnects between the two Murphys’ very different perspectives. Dave seems convinced that a just energy transition must be pursued to address the fundamental underpinnings of our current metacrisis; Tom seems convinced that such a transition, even if possible, could not be sustained over ecologically relevant timescales and might even accelerate the damage. Tom believes that modernity cannot be salvaged in any meaningful sense, while Dave considers the assertion that we cannot fix our problems to be an abrogation of our collective responsibility.
There is also a big difference in perspective about the timescales that we should be paying attention to: an optometrist might diagnose Dave with myopia (nearsightedness) and Tom with hyperopia (farsightedness), but it’s a significant challenge to bridge visions of decadal timescales with millennial ones (we need bifocals!). Another significant disconnect stems from values: should we place more emphasis on reducing suffering among humans alive today or in the near future (as Dave might propose), or on enabling humanity and other species to flourish for millennia to come (as Tom would suggest)? A final distinction I’ll note concerns agency: Dave is firmly convinced that humans control our destiny, while Tom emphasizes the limitations imposed by the boundary conditions of our finite planet and ecosystem.
However, it’s also worth emphasizing that our two interlocutors have much in common beyond their last names and years of work with the Planetary Limits Academic Network. Both agree that modern human practices are not sustainable, and that continuing on our current path increases both the risk of collapse and its severity. For either Murphy, business-as-usual is simply not an option. Also, both clearly care deeply about the happiness and well-being of both humans and our more-than-human kin, albeit perhaps in different proportions.
Yet it was striking to me how different our two Murphys’ worldviews are, despite sharing a broadly similar understanding of the facts of our current predicament. At times, it seemed like they were talking past each other, unable to understand how the other saw things. Dave maintains a surprising (if not also inspiring) optimism that humanity can craft a bright future through an energy transition, while Tom clearly thinks that, for modernity, the party’s over. In this Tale of Two Murphys, it seems it was the best of times, it was the worst of times.
This interview has been edited and condensed for length. This interview concludes a series that features conversations between Dave Murphy and Tom Murphy on the polycrisis and planetary limits.
Read the whole series: Part One | Part Two | Part Three | Part Four
