Peter Medawar’s “The Limits of Science”

Owen Hannaway
Owen Hannaway

W.J. Astore

Note to reader: I wrote this back in 1988 when I was a first-year graduate student in the history of science at Johns Hopkins University.  I took my first graduate seminar with Owen Hannaway, a distinguished professor of early modern science and alchemy.  He asked us to do a book review, and I chose Peter Medawar’s The Limits of Science.  I dedicate this article to the memory of Owen Hannaway (1939-2006), a distinguished scholar and a gallant man.

The Limits of Science is an intentionally short book dealing with topics in the history and philosophy of science. It consists of three different essays written in three different styles, yet it yields a general outlook on science which can be nicely summarized.  Sir Peter sees science as the most successful of man’s enterprises, but he is quick to observe that science has limits, although the growth of science itself is not self-limited.

Medawar first defines science.  Science, he says, is not a mere collection of facts but organized knowledge, knowledge that can be used to predict the behavior of the sensible world.  Medawar is careful to emphasize the difficulty of obtaining scientific knowledge, and the need for confidence based on trust within the scientific community.

Medawar then discusses whether there is such a thing as the scientific method and traces the development of different approaches.  Before the Renaissance, deduction in the form of the Aristotelian syllogism was used to advance science, while intuition and revelation were used to support science.  For philosophers in the Middle Ages, divine revelation guaranteed absolute certainty.  Francis Bacon lit a new path for enlightenment in the late sixteenth and early seventeenth centuries through the use of induction.  Bacon’s new method was the development of general premises through the use of experimentation and the collection of observations.  The frontispiece of Bacon’s Novum Organum summed up the new ideal of Plus Ultra (more beyond): it depicted the pillars of Hercules with a biblical inscription (Daniel 12:4) prophesying the advancement of knowledge.

Medawar next examines deduction and induction and finds them lacking.  The chief difficulty with deduction is that it begs the question; it can only discover something already contained in the major premise, therefore it is not a way to new knowledge.  By comparison, a major premise arrived at through induction cannot contain more information than the sum of its known instances.  A theory consisting of a legion of facts summarized by an iterative inductive process can thus be overthrown by a solitary contradictory instance.  In sum, a deductive premise merely makes explicit information that is already present in the premise, while an inductive premise is no better than the sum of its parts.  Neither method leads to new knowledge.

Considering these arguments, Medawar sides with the conclusion of Bertrand Russell and Karl Popper that there is no scientific method.  The myth of induction as the method for scientific advancement, developed by John Stuart Mill and Karl Pearson in the nineteenth century, persists today mainly because it agrees best with the public’s conception of science and the scientist’s desire for a positive self-image.

What then is the catalyst for advances in science? Medawar adopts Shelley’s idea of poesis in poetry: creation through the act of imagination.  The source of scientific hypotheses is these flashes of vision, and it is these hypotheses which guide and limit further science.  Medawar clearly rejects the idea that scientific discovery can be premeditated and cites the role of luck in scientific discovery.  He carefully qualifies the role of luck by showing how the scientist places himself in a certain mindset amenable to luck through his studies and associations with other scientists.

Medawar’s last essay discusses the limits of science. His fundamental assertion is that science does not yield absolute knowledge, and he quotes Kant as support: “Hypotheses always remain hypotheses, i.e., suppositions to the complete certainty of which we can never attain.” Science’s goal then is not the absolute but the nearest approximation possible; the nearer the approximation, the better its predictive capability.

Continuing the discussion, Medawar observes that there could be either a cognitive inadequacy or a restriction arising out of the nature of the human reasoning process that limits the growth of science, but since any such limitations would be present from conception we would never know of them (just as we could never perceive the Pythagorean celestial music due to its continuous presence in our lives). Are there then limits of science?  Not if science is understood as the art of the soluble.  If something is possible in principle, Medawar states, it can be done if the intention is sufficiently resolute and sustained.

The one limit to science as Medawar sees it is that it cannot answer ultimate questions, e.g. “Does God exist?” Medawar goes on to say he is not indicting science; rather he is recognizing that these questions require transcendent answers, which neither arise from nor require validation by empirical evidence.  He actually takes this argument one step further and asserts these questions have no possible answers. (Medawar recognizes that Immanuel Kant felt the opposite; since somehow man’s nature drives him to ask these questions, Kant felt that answers necessarily exist.)

According to Medawar, the question of whether God exists is outside the realm of science; the leap of faith required for a belief in God is one he himself is unwilling to make.  Although Medawar did not personally believe in transcendent answers, he did feel that these answers had a usefulness measured by the peace of mind they bring people.

I bought this book because as a Roman Catholic I was interested in what a scientist had to say about the limits of science in answering ultimate questions.  Medawar confirmed my suspicions that science can play at best only a subsidiary role with regards to these ultimate questions and the religious beliefs they help spawn.

For anyone looking for an introduction into what science is, how it advances, and what questions it can and cannot answer, Medawar’s book is excellent.  Perhaps the one idea I am always left with after reading this book is although science has limits, as long as man retains his ability to create imaginative hypotheses and his inclination to ascertain whether his guesses correspond to reality, there will always be more beyond for intrepid explorers in the realm of science.

Professor Hannaway appended the following note at the end of my review:

“What do you think your reaction would have been if you had read a book by a scientist less sympathetic to the claims of religion?  Perhaps you can find one, read it, and then critically assess the arguments of Medawar.”

“Why do you think a famous scientist like Medawar was so concerned by such questions to write about them in this way?  Could you find out something about his life that might explain this?  Try sources like the Times obituary columns, Nature, Notes and Records of the Royal Society.”

That was Owen: always generous with advice, and always trying to spur you to dig deeper, to learn more.

Bonus Anecdote: I’ll never forget this saying of Owen’s: “Scotch is for after dinner.” The last time I saw him in Denver at a conference, I was really pleased to track down a glass of single malt whisky for him.  He was a wonderful man.

STEM Education Is Not Enough

Sir Peter Medawar
Sir Peter Medawar

W.J. Astore

If you’re in education, you’ve heard the acronym STEM. It stands for science, technology, engineering, and mathematics.  As a country, the USA is behind in STEM, so there are lots of calls (and lots of federal money available) for improvements in STEM.  Usually the stated agenda is competitiveness.  If the US wants to compete with China, Japan, Europe, India, and other economies, our students must do better in science and math, else our economy will atrophy.

Here’s a sample rationale that can stand in for hundreds of others: “International comparisons place the U.S. in the middle of the [STEM] pack globally,” said Debbie Myers, general manager of Discovery Communications.  And for corporate managers like Myers, that’s not good enough when competition in the global market is both endless and the means to the end, the end being profit.

I’m all for STEM.  I got my BS in mechanical engineering and worked as an engineer in the Air Force.  I love science and got my master’s and Ph.D. in the history of science and technology.  I love science fiction and movies/documentaries that explore the natural world around us.

And that’s one thing that bugs me about all this emphasis on STEM.  It’s not about curiosity and fun; it’s not even about creativity.  STEM is almost always pushed in the US in terms of market competitiveness.  STEM, in other words, is just another commodity tied to profit in the marketplace.

My other bugaboo is our educational establishment’s focus on STEM to the exclusion of the humanities.  At the same time as the humanities are undervalued, STEM is reduced to a set of skills as mediated and measured by standardized tests.  Can you solve that equation?  Can you calculate that coefficient of friction? Can you troubleshoot that server?  Results, man.  Give me results.

Sir Peter Medawar, a great medical researcher and a fine writer on science, spoke of scientific discovery as an act of creation akin to poetry and other so-called liberal arts.  Nowadays, we simply don’t hear such views being aired in US discourse.  STEM as an act of creation?  As a joyful pursuit? Bah, humbug.  Give me results.  Give me market share.  Make me Number One.

If we as a nation want to encourage STEM, we should be focusing not on rubrics and metrics and scores.  We should instead be focusing on the joy of learning about nature and the natural world. How we model it, manipulate it, understand it, and honor it by preserving it.  STEM, in other words, must be infused with, not divorced from, the humanities.  Why?  Because STEM is a human pursuit.

As we pursue STEM, we should also honor our human past, a past in which we’ve learned a lot about ethics, morality, and humane values.  The problem is that STEM education in the US is often present- and future-focused, with little time for the past.

In American society, those with respect for old ways and traditional values are often dismissed as Luddites or tolerated as quaint misfits (like the Amish).  After all, Luddites aren’t competitive. And Amish quilts and buggies won’t return America to preeminence in science and technology.  The US as a nation has nothing to gain from them.  Right?

Here’s the problem.  We connect STEM to material prosperity.  We dismiss those who question all this feverish attention to STEM as anti-science or hopelessly old-fashioned.  But there’s a lot we can from the humanities about ourselves and our world.

To cite just one example: Consider this passage from Jacob Burckhardt, a great historian writing during the industrial revolution of the late 19th-century:

material wealth and refinement of living conditions are no guarantee against barbarism. The social classes that have benefited from this kind of progress are often, under a veneer of luxury, crude and vulgar in the extreme, and those whom it has left untouched even more so. Besides, progress brings with it the exploitation and exhaustion of the earth’s surface, as well as the increase and consequent proletarianization of the urban population, in short, everything that leads inevitably to decline, to the condition in which the world casts about for ‘refreshment’ from the yet untapped powers of Nature, that is, for a new ‘primitiveness’ – or barbarism.”

What a party-pooper he was, right? Most of what the US defines as STEM is about “material wealth” and “refinement of living conditions,” the very definition of “progress,” at least for those out to make a buck off of it.

Burckhardt was warning us that “progress” tied to STEM had its drawbacks, to include the exhaustion of the earth’s resources as well as the exploitation of human labor. Divorced from ethics and morality, STEM was likely to lead to “primitiveness,” a new barbarism.

Tragically, Burckhardt was right. Consider the industrialized mass murder of two world wars. Consider the “scientific” mass murder committed by the Nazis. (By the way, the Nazis were great at STEM, valuing it highly.)

In a democracy, STEM divorced from the humanities is not “competitive,” unless your idea of competition is barbaric. Disconnected from humane values, a narrow education in STEM will serve mainly to widen the gap between the 1% and the rest of us while continuing to stretch the earth’s resources to the breaking point.

Education in STEM, in short, is not enough. But you won’t learn that by listening to corporate CEOs or presidents prattle on about competitiveness.

For that wisdom, you need to study the humanities.