welcome covers

Your complimentary articles

You’ve read one of your four complimentary articles for this month.

You can read four articles free per month. To have complete access to the thousands of philosophy articles on this site, please


Pascal’s Climate Wager

Keith Tidman considers the smart bet for our future.

There’s general scientific agreement that something bad is going on with the world’s climate. Contention starts to loom large, however, when the conversation swivels inevitably to why and how that change is happening, and whether we can or even ought to do anything about it. Some people assert that natural cycles traceable over tens of thousands of years are causing the change, and conclude that the science to the contrary is inconclusive at best or even outright bogus – skewed, it’s disdainfully claimed, by the ideologues in order to acquire advantage. Others assert that humans are indeed major contributors to climate change, starting in the nineteenth century with the Industrial Revolution and societies’ sharp turn to fossil fuels to make their economies hum. These scientists contend that the evidence leads us to human causes of climate change, as shown by various metrics, such as the spike in carbon dioxide levels coinciding with the advent of hydrocarbon-fuelled technologies. One might say, it’s less about pro-science or anti-science as it is about ‘whose science’.

The landscape is made all the murkier because of flailing dogma and partisan politics, as each side attempts to diagnose the other’s allegedly parochial intentions. Combustible terms like ‘denier’ and ‘alarmist’ get bandied about incautiously, however. Wherever that sparring ultimately might lead, the world faces the quandary of choosing between two distinctively alternative approaches to what to do: nothing, or everything we can.

The first response is to put our faith in Mother Nature cycling through her natural changes back and forth, with human civilisation taking our lumps as nature sees fit. The second approach is to implement interventionist measures to redirect the path of human activity so as to try to mitigate, or better, to reverse, climate change’s more dire effects on the ecosystem, on sea levels and on the weather’s increasingly violent extremes.

Given there’s uncertainty as to the particulars of climate change and a range of possible interventions to take, to help us decide what to do we might borrow the kind of logic used by the French philosopher and mathematician Blaise Pascal’s (1623-1662) in his famous ‘Wager’, described in his Pensées, or Thoughts. Blaise Pascal was a polymath: a philosopher, mathematician, physicist, inventor, and theologian. Despite the four-hundred-year provenance of ‘Pascal’s Wager’, it is untarnished in its simplicity, and is useful even for the modern era’s climate-change crises. Whatever the cause, the stakes, in the matter of weather extremes and their effects upon many dimensions of people’s lives globally, are the same, and globally shared. In that context, let’s briefly explore how the Wager might serve both parties in the climate discussion.

Growing Concern
Growing Concern by Friedrich Farshaad Razmjouie, 2022

Pascal’s original Wager was about betting on the heady matter of the existence or nonexistence of God and an afterlife, and which bet – belief or unbelief – made the most sense from a maximising-winnings standpoint. Pascal’s Wager begins with the assumption that we can neither prove nor disprove the existence of God: that God’s existence or nonexistence is in essence unconfirmable and unknowable. So, instead, Pascal turned to the matter of belief, not proof. On the basis of early decision theory and risk analysis, Pascal argued that it makes sense to put your trust in God and act accordingly. If God does exist, if you had put your trust in him you will be rewarded with eternity in heaven; whereas if you did not, you will be punished eternally. But, if God does not exist, then an erroneous belief in His existence bears no more consequence than disbelief does: you will die, and that will be that. The most prudent wager is therefore to trust God, and to act fittingly.

Now let’s fast-forward almost four centuries, and apply the Wager’s formulation to our choices regarding climate change.

The going-in idea for this thought experiment is that climate change exists. In that fact there is general agreement, even if not a consensus. What people generally disagree on is the cause, the extent, the consequences of the change, and what to do about it. But using Pascal’s Wager, there’s no longer a need to joust over the disagreements. Just as with Pascal’s original Wager, being right in the belief that humans cause climate change and responding to it positively will matter a lot; being wrong and responding will matter comparatively little. In this framework, if we decide to act on the assumption that climate change is rooted in human activity, the consequences of those interventions will be positive whether we’re right or wrong about the causes of it. For example, more renewable energy would still be good even if there were no anthropogenic climate change. Alternatively, if we wager not to act on the assumption of human activity being the cause of climate change, but we’re wrong, and it is, then the consequences will be catastrophic – living with unmitigated climate change and its impacts around the world. To put this another way, if we are responsible, then the results of acting on this or not will be significant, either positively or negatively respectively, whereas if we’re not responsible, the cost of believing that we are will be comparatively low. So to act on the belief that human activity is significantly contributing to climate change is by far the best bet.

Again, this wager is not about proof. Instead it’s about what the best bet on what to do is in the face of the lack of definitive proof. So one advantage of applying Pascal’s Wager to climate change is that it handily relieves both sides of having to pick between natural or human causes of the changes. Neither party has to worry about who has the higher rational ground. No one needs to prove or disprove anything, scientifically or otherwise, before acting. No need to finger-point. Rather, acting as if humans cause climate change is the rational bet. So we ought to wager that human-caused climate change is real, that its consequences are dire, and that systematic intervention will mitigate it.

© Keith Tidman 2022

Keith Tidman has written extensively about social and political philosophy and science, and is the author of a book on the history of naval operations analysis.

This site uses cookies to recognize users and allow us to analyse site usage. By continuing to browse the site with cookies enabled in your browser, you consent to the use of cookies in accordance with our privacy policy. X