The Horizon Bias in Human Innovation
In an age that offers seemingly limitless technological promise, it makes sense to step back, suspend our credulity, and consider why we are so inclined to believe that what could happen will happen soon. We should remain hopeful, but also aware that nature will always be cleverer than we are.
WELLINGTON – We are beguiled by technology and what it can do for us, be it colonizing Mars, ending human aging, or connecting the entire world within a single network. But, especially in an age that offers seemingly limitless technological promise, we should step back, suspend our credulity, and consider why we are so inclined to believe that what could happen will inevitably happen soon.
Consider the case of cancer, that most vexing of diseases. Modern bio-, nano-, and other technologies promise us a “cure,” such that one can now easily imagine a “world without cancer.” And yet there is little reason to expect a decisive victory over cancer anytime soon.
To be sure, we already have therapies that can kill most cancer cells. The problem is that killing 99% of cancer cells is not the same thing as killing 99% of enemy soldiers in a war. The cells that resist the near-cure multiply, enabling the tumor to make up lost ground. And while we can address this problem with better targeting, there is a persistent gap between the near-cure and the cure. As Siddhartha Mukherjee shows in his best-selling “biography of cancer,” The Emperor of all Maladies, that is why the fight against cancer has been a long story of dashed hopes and overwrought expectations.
Suppose we could go back to 1971 and talk to the scientists who advised US President Richard Nixon when he launched the original “War on Cancer.” I suspect they would be amazed by today’s treatments, such as immunotherapy and biotech interventions that interact in sophisticated ways with the molecular bases of our immune systems. To earlier generations, these technologies would look like the stuff of science fiction: The Cure.
But then we would have to show our colleagues in 1971 the current cancer statistics. They would see vast improvements over the cancer trends of their own time. But they doubtless would be dismayed to realize that a cure has eluded even such technological marvels. (We would then have to tell the Apollo 11 generation that we have not set foot on Mars, either.)
Owing to our current understanding of the human body and our rapidly advancing technological capabilities, we take it for granted that cancer is curable “in principle,” just as we assume that carbon capture and storage technologies could, in principle, offer a simple fix for climate change. Because we can see – or at least envision – the horizon, we think that we can reach it in due time. But cancer is an endemic feature of our organic existence. As Mukherjee puts it, to rid ourselves of cancer we must seemingly “rid ourselves of the processes in our physiology that depend on growth – aging, regeneration, healing, reproduction.”
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Still, for as long as we have been searching for a cancer cure, we have fallen victim to the “horizon bias.” In the 1940s, the American physician Sidney Farber gave antifolates to leukemia patients and produced unprecedented – but temporary – remissions. Upon first witnessing this breakthrough, it would not have been unreasonable to think that the end of leukemia was in sight.
Similarly, in the 1990s, the medical researcher Judah Folkman discovered that angiogenesis inhibitors could be used to cut off the blood supply to tumors. “Judah is going to cure cancer in two years,” predicted James D. Watson, the Nobel laureate who co-discovered DNA. Folkman himself was more modest: “If you have cancer and you are a mouse, we can take good care of you.” Even this more considered assessment exaggerated the immediate therapeutic benefits of the discovery. Nonetheless, Watson doubled down two years later: “I said that Judah Folkman would cure cancer within two years. I was wrong. But he will do it in another two years.”
The horizon bias prevented these otherwise informed observers from appreciating the complexity of the challenge at hand. Two decades later, the most notable application of Folkman’s discovery is bevacizumab (Avastin), a cancer drug that modestly extends some patients’ lives at massive expense.
Clearly, the outcomes we can imagine are not necessarily those we should rationally expect. Missing from the confident forecasts of cancer’s impending demise is the role played by evolution.
According to the “second rule” of Leslie Orgel, one of the foundational theorists of the origins of life, evolution is cleverer than we are. In terms of complexity, human hearts, eyes, and immune systems remain far beyond the scope of anything humans could design themselves. The cancer that will kill many of us if we live long enough starts from a single cell that divides continuously while evading the immune system. A disease that emerges within us and evades our own immune system can probably evade our most powerful immunotherapies, too. Methods of tweaking our immune systems may yield many treatments, but they will not provide The Cure.
The persistence of autoimmune diseases such as diabetes, multiple sclerosis, and lupus underscores our incomplete knowledge of the immune system. Once we have defeated these diseases, we might be closer to becoming as clever as evolution – at least in our understanding of immunity. And only then could we start betting on immunotherapies that can wipe out cancer.
This is not an argument for fatalism or inaction. We should remain hopeful that the societies of 2525 will have eliminated cancer, fixed the climate, and opened up hotels on Mars. But we should expect that they will not have overcome the powerful bias that leads those with knowledge of a problem to believe that a solution is imminent.
The horizon bias is a double-edged sword. The ability to imagine alternative futures and answers to far-reaching questions is the source of all human ingenuity and innovation. Throughout history, and especially since the Enlightenment, the recognition that we can decipher the operations of nature has fed the pursuit of knowledge and allowed for the invention of ever-more sophisticated technologies.
We should not regret this thirst for understanding, but nor should we overestimate our own capabilities. When ambitious promises go unmet, the public’s inflated expectations can quickly give way to cynicism and distrust. As we celebrate the marvels of our technological age, we should be careful not to succumb to hubris. The universe will always be cleverer than we are.