I have just finalized a book chapter in which I have argued that the philosophy of Alfred North Whitehead can inform contemporary transport research in a number of ways. That may come as a surprise, given that this mathematician-philosopher published his major philosophical works in the 1920s and 30s — a time when scholars were trying to come to terms with the consequences of Darwin’s work, Einstein’s theories and Quantum theory for how life and the world were to be re-imagined.

But it is not, for a variety of reasons. One of these is that Whitehead’s offers an interesting perspective on questions of indeterminacy and uncertainty with regard to how transport systems evolve over time. In a way his philosophy anticipated contemporary concerns over ‘deep uncertainties’ — situations in which analysts cannot enumerate which futures are more likely to unfold because they do not fully understand, or cannot agree on, the causal mechanisms and functional relationships between the phenomena or processes being studied. It is no secret that transport planning is ill-equipped to deal with such uncertainties and often ignores these — even most forms of scenario analysis used in transport research fail to come to terms with fundamental uncertainty about the nature of causal mechanisms. Relatively recently, however, Walker and colleagues have begun to tailor and apply their adaptive policy making approach to transport planning.

This is not the place to fully review this approach. Suffice it to say that Walker c.s. build a range of steps and practices in the policy development process in which policy-makers have to appreciate vulnerabilities — factors that may complicate or compromise a policy’s success. Some of these can be anticipated (certain vulnerabilities) and other cannot be anticipated (uncertain vulnerabilities). A central idea of the approach is that policy-makers hedge themselves to the effects of those uncertainties and monitor whether some form of adaptation of the original policy is required.

Walker et al.’s approach has many strengths, and it would be great to see it applied in transport planning practice. But perhaps its central premises are also are also a weakness. For the approach assumes first of all that uncertainty over the nature of causal mechanisms will be reduced over time as event unfold and second that, as things will become clearer and more information becomes available, policy-makers can respond to those and adapt policy action if and when needed. But what if uncertainty is more profound? What if the nature of causality is such that it only can be understood with hindsight, when the tables have turned? In that case adaptation can only be reactive rather than proactive.

It might be argued that situations like these resemble Taleb’s black swans but they may occur more often and with (much) more limited ramifications. It seems to me that Whitehead’s philosophy offers one way to think about these situations. Now, his philosophy is notoriously difficult and technical, and I won’t be able to do any justice to it here. Readers would need to turn to Process or Reality or alternative the Adventures of Ideas.

Let me therefore say this: According to Whitehead’s philosophy the world consists completely of events, and these can be broken down in ever smaller events until one arrives at the smallest possible ‘unit’ of event (which he called ‘actual occasion’). Crucially, how these actual occasions unfold can never be known fully in advance. There is always an immanent possibility that something new or unexpected will happen, however dim this possibility may be. Indeterminacy can never be ruled out completely. Uncertainty is not epistemic — a consequence of lack of knowledge — but ontological and hence an irreducible part of the world itself. The question then is under what circumstances it is more or less problematic to make (reasonable) assumptions about the nature of causal mechanisms.

The full consequences of a Whiteheadian perspective on uncertainty for transport research and planning obviously need much more thought, and I would expect that they will make many researchers profoundly uneasy. As an example consider the following: if one can never be fully sure about the character of causal mechanisms of (future) events, then all research into such matters is by definition speculative. There can be no — and arguably should not be any — separation between the practices of the researchers and research outcomes. Whilst ideas such as these may be rather common to many scholars with a background in science studies, I suspect they will be difficult to accept for quite a few transport researchers and planners.

Even so, I believe that transport planning and research can benefit immensely from sustained engagement with Whiteheadian perspectives on uncertainty and causality.