In the sometimes arcane and pedantic world of philosophy of science, there is a concept referred to as the “pessimistic induction from the history of science”. This is a fancy way to articulate a rather cynical (but mostly reasonable) conclusion one might draw from considered reflection on the history of scientific discovery. The basic point is this: the history of science is a veritable graveyard of failed ideas. Interred therein and littered about the tombstones are discarded hypotheses and wishful ideas that failed to pass muster. Read the inscriptions on the tombstones and you’ll find elegies to hopeful – even occasionally ingenious – but fatally flawed theories, including some produced by the sharpest intellects in history. J. J. Becher’s mid-17th century phologiston theory of combustion, which held sway until Lavoisier disproved it in the late 18th century; Ptolemy’s geocentric model of the solar system; Newton’s many forays into astrology; any number of pre-germ theory explanations for infectious disease; Jean-Baptiste Larmarck and Erasmus Darwin’s ideas about biological evolution; even Charles Darwin’s ideas on pangenesis and gemmules as mechanisms of inheritance. In this respect, the history of science is very much like the history of life on earth. The millions of species living today are but a tiny fraction of the species that have ever existed. Similarly, today’s most robust and elegant theories are but a tiny sampling of the multitude of explanations humans have forwarded over the years.
Given this, one might be forgiven for wondering why some people put so much stock in science. If most scientific theories turn out to be wrong, why invest confidence in the process that produces them? This is a valid question, one that has provided fodder for much speculation on the part of scientists and philosophers alike. Multiple answers have been forwarded, but there are a few I think worth highlighting here. First, there is a matter of logical bookkeeping. Inductive reasoning does not prove anything one way or another, at least not with the resounding finality many of us ascribe to the word prove. For instance, the best reasons for thinking the sun will rise tomorrow do not relate directly to the fact that it has risen every day previously. Rather, they have more to do with the type of object the sun is, an understanding of the kinds of processes at work within it, the intricate gravitational relationships between it and the other massive objects occupying its solar neighborhood, and the regular rotation of the earth. Similarly, the confidence assigned to science is not entirely dependent on a strict accounting of its history of successes and failures, but an understanding of the way science works as a process. Though science has produced hordes of failed ideas, it also includes the very mechanism by which the flaws in those ideas were uncovered and their faulty premises ultimately rejected. Science, as the saying goes, is a self-correcting process. The constant push and pull of cooperation and conflict within scientific communities, in relation to the cold arbitration of external reality and empirical evidence, provides an excellent check against the proliferation of bad ideas. Second, it is possible to invert the pessimistic induction and derive an optimistic induction. This stems from the fact that science has, on occasion, produced powerful and elegant explanations for the way the world actually works. And, importantly, it is the only thing that ever has. True, most scientific ideas fail. But some succeed, and our understanding of the universe increases as a result. This claim is exclusive to science – it can be made for literally no other human process.
Let me be precise about what I mean by this. There is a relatively widespread opinion, at least in some subset of Western society, that there are multiple ways of “knowing”. This idea is justifiable, but only in a very restricted sense (i.e. if the word “knowing” is loosely construed as a statement regarding the subjective experience of meaning and profundity). Art can teach individuals much about what it means for them to be a human with respect to various aspects of their environment. Literature is able to explore difficult and profound moral questions and produce moving ideas about society and culture. It is even capable of commenting on the very nature of science and knowledge. In this sense, art, music, literature – in addition to any number of humanity’s myriad cultural traditions and social philosophies – can reveal things about who we are as a species and where we sit in the cosmic tapestry that are both profound and illuminating. They are powerful tools for the construction of meaning. The meanings produced by art, literature, religion, and so forth are infinite and occasionally beautiful. That they are irrevocably subjective and intensely individual does not diminish their incredible value. It only means that they are not candidates for founts of universal and unequivocal “knowledge”. Conversely, Newton’s laws of motion are not necessarily relevant to everyone, everywhere. Most people live full and meaningful lives without a comprehensive understanding of them. Nevertheless, they are an incredibly accurate, useful and – as near as anyone can tell – universal description of a set of physical relationships. Only science has ever come close to producing anything approximating a universal or unequivocal “truth”. Yet it does so with enough humility to call its best ideas provisional. There may indeed be other “ways of knowing”, but only in a limited sense. Non-scientific ways of knowing have never cured a disease or explained the origins and diversity of life on earth, put a human on the moon and provided a glimpse into distant galaxies or the earliest moments of the universe. And that is precisely why, when it comes to science, I am a grinning optimist. It is also why it is not only justifiable to invest confidence in scientific, but immensely rational to do so.
Here is your token inspirational science video: Richard Feynman on the beauty of a scientific attitude.