杏吧原创

IN DECEMBER 2005, Judge John Jones III had a difficult decision to make. For 40 days he had listened to the testimonies of biologists, sociologists, philosophers and parents as they argued for and against the teaching of intelligent design in public schools in Dover, Pennsylvania.

It was obvious that the proponents of ID were trying to push a religious agenda into government-funded schools, violating the separation of church and state. Nonetheless, Judge Jones鈥檚 task was not simple. He had to rule on whether or not ID is science, and distinguishing science from pseudoscience is harder than it might seem.

famously took on this so-called 鈥渄emarcation problem鈥� in the 1930s, arguing that scientific hypotheses differ from pseudoscientific ones in that they can be falsified through experiment. Today, many scientists continue to see falsification as the hallmark of good science (physicist refers to them as the 鈥淧opperazzi鈥�), despite the fact that philosophers have long since realised that science can鈥檛 be wrapped up quite so neatly.

Hypotheses do not exist in a vacuum 鈥� they come with all kinds of built-in assumptions about the world, scientific instruments and experimental set-ups. A negative result might falsify the hypothesis 鈥� or it might simply require a revision of an auxiliary assumption.

So how can we decide what counts as science? That is the central question of this brilliant book, which ought to be required reading for, well, everyone.

Pigliucci, a philosopher of science at City University of New York, begins by arguing that science is not one thing 鈥� it is a mixed bag of practices ranging from physics and chemistry in the 鈥渉ard sciences鈥� to sociology and anthropology in the 鈥渟oft鈥�. What they all have in common, he says, is the construction and testing of hypotheses with systematic observations or experiments.

It quickly becomes apparent, however, that this definition isn鈥檛 enough. For something to count as science, it also needs some kind of explanatory framework. General relativity is science not only because it makes predictions that have been confirmed by observations, but also because it has a beautiful internal consistency: it explains not only how gravity should behave but what it is.

鈥淚f something is to be counted as science, it needs some kind of explanatory framework鈥�

Astrology is different. When studied scientifically, astrological predictions have failed miserably time and again 鈥� but that doesn鈥檛 make it pseudoscience, that just makes it wrong. However, astrology is indeed pseudoscience, Pigliucci says, because it lacks a consistent explanatory framework. Constellations aren鈥檛 real, they are optical illusions resulting from our lack of depth perception when it comes to the night sky, so how can they influence human behaviour? And what physical force mediates their influence?

When Judge Jones issued his ruling, he declared that ID is not science because it invokes supernatural causation and because it 鈥渆mploys the same flawed and illogical contrived dualism that doomed creation science in the 1980s鈥�. A contrived dualism is a false dichotomy 鈥� if evolution is wrong then ID must be right 鈥� and it highlights ID鈥檚 lack of explanatory power. ID is nothing more than an attack on evolution; in and of itself it is nothing more than a belief in God. To see what I mean, try this experiment if you ever find yourself talking to a proponent of ID. Say, 鈥淥K, for the sake of argument let鈥檚 say evolution is wrong and let鈥檚 forget about it. Now tell me how intelligent design works.鈥� Having tried this a few times myself, I am confident that you will be met with nothing but an awkward silence.

General relativity and ID occupy opposite ends of the spectrum that runs from science to pseudoscience, but many fields occupy the murky region in between. Pigliucci names evolutionary psychology, the search for extraterrestrial intelligence (SETI) and string theory as examples of 鈥渁lmost sciences鈥�. These fields are not pseudoscience, he says, but they鈥檙e not bona fide science either. Evolutionary psychology often lacks even the possibility of hard data, while SETI鈥檚 central hypothesis may not be falsifiable since negative results 鈥� silence 鈥� are what SETI researchers largely expect to hear. As for string theory, he says, it may be testable in the future, but it isn鈥檛 yet (though I would argue that recently discovered mathematical dualities between string theory and ordinary quantum field theory do make it possible today).

What keeps these 鈥渁lmost sciences鈥� from slipping into pseudoscience is their grounding in real science: evolutionary psychology in evolutionary biology, SETI in astronomy and biology and string theory in fundamental physics. By contrast, quantum mysticism is rooted in a misunderstanding of quantum physics, while ID is rooted in religion.

Pigliucci doesn鈥檛 just cut through the academic debate, he also offers insightful analysis of today鈥檚 anti-scientific climate. This has come about, he argues, through a confluence of factors: rising anti-intellectualism; a decline in the quality if not quantity of public intellectuals helping to shape public opinion; and a rise in the number and influence of privately funded think tanks whose job it is to influence political debate using propaganda dressed up as data. This, he says, is compounded by the media glossing over nuances in favour of catchy but misleading sound bites, and downright bad reporting that completely misrepresents scientific knowledge.

Philosophers shoulder some of the blame, too. 鈥淭he whole postmodern wave in late-twentieth-century philosophy鈥� hasn鈥檛 helped by producing egregious examples of nonsense on stilts,鈥� Pigliucci writes, 鈥渟uch as philosopher Paul Feyerabend鈥檚 contention that astrology and magic are as legitimate as science, or Michel Foucault鈥檚 overly simplistic statement that there are no universal truths.鈥�

The idea that science can鈥檛 tell us anything about the objective world just because it is a human activity fraught with human flaws and biases is easily refuted the minute that planes fly or atomic bombs explode. 杏吧原创s, meanwhile, do us a disservice when they promote scientism 鈥� the idea that science can answer every meaningful question we might ask about the world.

Between postmodernism and scientism lies a middle way by which objective knowledge of the world can emerge. We ought to think about science as a Bayesian algorithm, Pigliucci argues, echoing the sentiment of many contemporary philosophers of science. Bayesian algorithms calculate probabilities of future events or observations based on prior knowledge. As we gain new knowledge, we feed that back into the equation, 鈥渦pdating our priors鈥� and leading to increasingly accurate predictions. In this way, little by little, science nudges us closer to understanding the way the world really is.

The boundaries between science and pseudoscience are fuzzy and hard to pin down, but if there鈥檚 anyone who can help us with that, it鈥檚 the philosophers of science. I came away from this book thinking that philosophers really ought to have a greater role in public discourse 鈥� and I don鈥檛 just say that because it happens to be my own academic background. Yet ask any intelligent layperson, science journalist or even scientist to name a philosopher of science and you鈥檒l often get a blank stare in return.

Philosophers of science were some of Judge Jones鈥檚 best resources in the Dover trial and they are some of our best resources as a society dealing with the consequences of science in our everyday lives. Pigliucci is a perfect example.