Answers for Aristotle

How Science and Philosophy Can Lead Us to A More Meaningful Life


By Massimo Pigliucci

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How should we live? According to philosopher and biologist Massimo Pigliucci, the greatest guidance to this essential question lies in combining the wisdom of 24 centuries of philosophy with the latest research from 21st century science.In Answers for Aristotle, Pigliucci argues that the combination of science and philosophy first pioneered by Aristotle offers us the best possible tool for understanding the world and ourselves. As Aristotle knew, each mode of thought has the power to clarify the other: science provides facts, and philosophy helps us reflect on the values with which to assess them. But over the centuries, the two have become uncoupled, leaving us with questions — about morality, love, friendship, justice, and politics — that neither field could fully answer on its own. Pigliucci argues that only by rejoining each other can modern science and philosophy reach their full potential, while we harness them to help us reach ours.Pigliucci discusses such essential issues as how to tell right from wrong, the nature of love and friendship, and whether we can really ever know ourselves — all in service of helping us find our path to the best possible life. Combining the two most powerful intellectual traditions in history, Answers for Aristotle is a remarkable guide to discovering what really matters and why.




“Everything must have a purpose?” asked God.

“Certainly,” said man.

“Then I leave it to you to think of one for all this,” said God. And He went away.


WHEN I WAS A CHILD I WAS CHUBBY. THIS WAS A cause of major distress, between the taunting of some of my friends and the obvious disapproval of my parents, who kept bringing me to one diet doctor after another. Mind you, by the standards of today’s obesity epidemic my condition would have been barely noticeable, and it is quite amusing that nowadays I have to order my clothes online because it is difficult to find clothes in stores that are small enough to fit me. Still, the problem significantly affected my quality of life from the time I can remember being conscious of it (when I was in elementary school) to my early thirties, when I decided that I ought to do something about it, my way.

I began by doing the obvious things: I read about the problem, signed up for a gym membership, and started forming an aesthetic and healthy relationship with food, as opposed to seeing it as a source of consolation for whatever might be going wrong in my life at any particular moment. It took effort, and to some extent it still does, but my quality of life—both physical and psychological—significantly improved in the span of mere months. Without knowing it yet, I was practicing what in this book I call “sci-phi”—short for the wisdom (and practical advice!) that comes from contemplating the world and our lives using the two most powerful approaches to knowledge that human beings have devised so far: philosophy and science.

The basic idea is that there are some things that ought to matter, whatever problem we experience in life: the facts that are pertinent to said problem; the values that guide us as we evaluate those facts; the nature of the problem itself; any possible solutions to it; and the meaningfulness to us of those facts and values and their relevance to the quality of our life. Since science is uniquely well suited to deal with factual knowledge and philosophy deals with (among other things) values, sci-phi seems like a promising way to approach the perennial questions concerning how we construct the meaning of our existence.

So, for example, let’s go back to the problem of diet and weight gain. As you might imagine, science has quite a bit to say about this subject, and yet the public is hardly aware of most of this knowledge, which is drowned out by shouts about yet another miracle diet, another miracle pill, or another superficially easy solution to the problem. For instance, Gina Kolata, in her 2008 Rethinking Thin: The New Science of Weight Loss, describes a landmark study by Rockefeller University researcher Jules Hirsch, who subjected a group of obese people to a monitored diet while they lived for a grueling eight months at the Rockefeller hospital. Hirsch started out knowing that obese people have much larger fat cells than people of normal weight, and he wondered what would happen to those cells after a rigorous diet: Would they degenerate? Would they get smaller? The results were clear: the fat cells of formerly obese patients had shrunk considerably by the end of the experiment, reaching standard size. Now that his subjects were back to normal, Hirsch thought, not only in overall weight but even on the cellular level, surely they would be able to stay thin, their problem solved. (This was 1959, much earlier than the current obesity epidemic.)

But things did not quite work out as Hirsch predicted: within a few months, all of his formerly obese subjects had gone back to approximately their original weight, despite the fact that they wanted to maintain their newly achieved thinness. Since this was science, and the patients were studied from a variety of perspectives under controlled conditions, the researchers were able to figure out what had happened. The metabolism of an obese person is actually normal, meaning that it is calibrated by the body to maintain the status quo. When the researchers put their obese subjects on a severe diet, they of course lost weight (simply as a result of basic laws of physics), but their metabolism slowed down enormously compared to that of a naturally thin person. In other words, their bodies interpreted the new regime as one of starvation, and a basic survival mechanism (keep the metabolism down, consume less) kicked in. Once the dietary restrictions were lifted, the subjects’ metabolism levels went back to normal, they felt an uncontrollable hunger, and they ate their way back to obesity.

Later studies not only confirmed these findings but uncovered the symmetrical truth that thin people who attempt to gain weight (sometimes by eating as much as an astounding 10,000 calories a day!) cause their metabolism to accelerate dramatically. As soon as they stop overeating their bodies burn all the extra fat, and they are back where they started. (Lucky bastards, one might add.) This kind of research, as well as studies on the genetic inheritance of body mass index (a function of your weight, and your height), all point to the conclusion that most of us have a “set range” in terms of both our metabolism and our weight and that our bodies become increasingly resistant to attempts to move much above or below our natural range. This most certainly does not mean that the environment has nothing to do with our weight, or that we cannot do anything about it. But it does mean that not only are there limits to what we can do, but there is a cost to be paid for doing it in terms of the precious psychological resource of willpower (more on that in Chapter 9). If people were more widely aware of this sort of research, they would have more realistic expectations about how to handle their weight problem, they would devise smarter ways to deal with it, and they would stop pursuing the chimera of a “silver bullet” that will quickly make them happy. Then again, the huge cottage industry that has flourished by exploiting people’s weaknesses about food would probably collapse overnight, with presumably disastrous consequences for all those who keep making money out of the craze for easy diets.

So much for the science. Where does the philosophy come in? All the facts about the inheritance of human weight, rates of metabolism, the size of fat cells, and so on are of only academic interest until they affect the lives of real people. But why do these facts affect our lives? One answer comes, again, from science: there are negative health consequences to being seriously overweight or obese. People who suffer from severe weight problems are more prone to diabetes and heart conditions, their life expectancy is significantly shorter, and of course the quality of that life is much diminished. Moreover, there are practical consequences for society, which devotes significant financial and other resources to treating conditions related to obesity.

But that is, of course, only part of the story. I was never obese, not even close, and yet the problem of being overweight has been with me my entire life. And I am most certainly not an isolated case: a multimillion-dollar industry of diets and exercise machines exploits the obsession with weight shared by millions of Americans. What is going on is that we make judgments concerning the issue of weight, judgments that range from aesthetic to moral in nature, and both aesthetics and ethics are branches of philosophy, not science.

If we feel ugly because we are overweight, it is because—probably unconsciously—we deploy a certain aesthetic theory of what an attractive human being should look like. This theory is informed, of course, by the culture in which we live (the concept of physical beauty has demonstrably changed over space and time throughout human history) and perhaps to some extent even by basic biological instincts. (There is evidence, for instance, that we prefer symmetrical features in a potential partner because such features are a reliable indicator of healthy genes that could be transmitted to our progeny.) Similarly, if we blame our excess fat on our lack of self-control, we are making a moral judgment about how we ought to live and behave, what we should strive for in life, and how much of our resources (both mental and financial) we should invest in achieving certain aesthetic standards. We are doing philosophy without realizing it, and there is a distinct possibility that bad philosophizing may make our lives more miserable than they perhaps should be.

This idea that philosophy and science can be combined to give us the best possible knowledge about the world and how to act within it is an old one, encapsulated by the classic concept of scientia, a Latin word that means “knowledge” in the broader sense, encompassing both the sciences and the humanities. In German, a similar term is wissenschaften, which also refers to more than just the English “science.” Arguably the first philosopher in the Western tradition to take the concept of scientia (or what I call sci-phi) seriously was Aristotle (384–322 BCE), a fellow whom the reader will see popping up throughout this book (which explains the title of the same). What is important about Aristotle and some of his fellow ancient Greek philosophers is not the content of their science, which has been dramatically outpaced by the developments of the past twenty-four centuries, and not even some of their specific philosophical positions, which are also no longer tenable in light of subsequent discussions. Rather, what is crucial to the idea of this book is the ancient Greeks’ fundamental concept that life is a project and the most important thing for us to do is to ask ourselves how we are to pursue it. In a sense, then, Aristotle was among the first to approach the big questions in both a philosophical and a scientific manner, and we are now beginning to have some good (if still provisional) answers to those questions.

For Aristotle this project meant engaging in a quest for eudaimonia, a Greek word that literally means “having a good demon” and that is often translated as “happiness,” though it should more properly be understood as “flourishing.” Eudaimonia is achieved by engaging in virtuous behavior—that is, doing the right things for the right reasons—throughout one’s existence. Since life thus conceived is a project, a full assessment of a life’s worth is actually not possible until we reach the end, a notion that still has a powerful intuitive appeal for us moderns. For instance, the lifelong reputation of someone who led a good life up to a certain point but then engaged in unethical behavior is diminished or crippled, and vice versa: we consider praiseworthy someone who began by faltering but then regained a high ethical ground.

Aristotle, a good psychologist, realized that it is often difficult to align our rational assessment of what we ought to do with our emotional inclinations toward doing what comes easily to us or is pleasurable. Going back to our example of physical well-being, we all know that it is good for our long-term bodily (and psychological) fitness to eat moderately and exercise regularly. Yet our penchant for immediate rewards pushes us to overindulge our appetites and makes us lazy when it’s time to get on the treadmill. Aristotle never saw a fast-food joint, but he knew about human fallibility. Indeed, he thought that the major obstacle to increasing our eudaimonia was something the Greeks called akrasia, translatable as “weakness of the will.” In a sense, to be virtuous means to rise above one’s weaknesses to do the right thing, both for ourselves and for others. That is the way toward human flourishing.

It should be clear, then, that eudaimonia is not “happiness” in the generic sense of a positive emotion, but that it is value-laden—that is, it is an intrinsically moral concept. The ancient Greeks would have argued, for instance, that a life devoted to the exclusive pursuit of physical pleasures, or wealth, or power, is not eudaimonic, regardless of how “happy” the person seeking such pleasures, wealth, or power might feel. In an important sense, these pursuits would all be distractions from eudaimonia, because the individual in question has done nothing to improve himself or to affect the world in a positive manner. Eudaimonia should not be confused with the Christian virtue of asceticism, or with Buddhist detachment: the Greeks from Aristotle to Epicurus (341–270 BCE) thought that physical pleasures like good food, love and friendship, and even a good dose of luck were all necessary ingredients of a eudaimonic life. They also thought, however, that we are best able to pursue the eudaimonic life by taking the time to reflect on it.

All of this notwithstanding, to most people these days philosophy seems like a quaint activity best left to a bunch of old white men with a conspicuous degree of social awkwardness. This is the twenty-first century: if science tells us that a certain weight range is good for our health and another is likely to trigger disease, shouldn’t a rational human being simply follow the doctor’s orders, philosophical disquisitions about aesthetics, ethics, and the meaning of life be damned? I don’t think the answer to this question is quite so simple, because of a crucial and much underappreciated distinction between facts and values. To derive the latter from the former is a type of logical error known as the “naturalistic fallacy” (because one is attempting to equate what is natural with what is good). One of the first to discuss the naturalistic fallacy (though he didn’t use that term) was the eighteenth-century Scottish philosopher David Hume (1711–1776) in his aptly titled A Treatise of Human Nature. Hume noticed that some people who wrote on a variety of factual issues (what is/what is not) eventually, seamlessly, and without explanation switched to an altogether different kind of discourse concerned with ethical imperatives (what ought to be/what ought not to be). Hume is not saying that there is no connection between facts and values, but he points out that a person invoking such a connection should explicitly justify it.

Hume’s conception of the naturalistic fallacy informs this book and its central idea that the conjunction of science and philosophy has much to offer in making the lives of reasonable human beings significantly better. Taking the naturalistic fallacy seriously, we acknowledge that science (dealing with matters of fact) is not enough; we also need philosophy (dealing with matters of value). But our philosophy can and should be informed by the best science available, and vice versa: our quest for scientific knowledge should be guided by our values. Our aesthetic judgment may want our bodies to be close to a particular weight range, and our moral judgment may fault us for not quite getting there. But a serious understanding of the biology of human metabolism will help us cut ourselves some slack and reach a compromise between what we would like to do and what biological reality allows us to do. Here science helps us revise our philosophical intuitions. That science should in turn be guided by our philosophical choices is also clear upon a moment’s reflection: why does so much money go into research on human weight loss and gain? Because according to our aesthetic and ethical values, that sort of investment is justified, presumably at the expense of other possible kinds of medical research, considering that our societal resources are not unlimited. Philosophy, then, guides the general direction in which science (and science funding) goes.

Of course, a clear distinction has been made between science and philosophy only rather recently in human history; not so long ago, in the seventeenth and eighteenth centuries, people like Galileo Galilei (1564–1642) and Isaac Newton (1642–1727)—who today would be considered scientists—saw themselves as “natural philosophers.” If science and philosophy were once one and the same, how do we account for their peculiar evolution so that nowadays they are treated as distinct enough to often be housed in different colleges on university campuses? And what can I possibly mean by “sci-phi,” the attempt to bring them back together in the service of human flourishing?

The evolution of science is perhaps easier to understand, if for no other reason than that more people are familiar with its products, from its discoveries about the nature of the world to the technological and medical applications of its principles. This familiarity notwithstanding, there are many misconceptions about science, which I tried to clear up in Nonsense on Stilts: How to Tell Science from Bunk. To begin with, there is no such thing as the “scientific method.” Science is a somewhat methodical enterprise, but every practicing scientist has one basic guiding principle: whatever works. Scientists are by nature pragmatic, and they will approach a problem from a variety of points of view, deploying an array of methods of investigation, until they reach a satisfactory answer to their questions.

One of the uncanny things about science is that, in often reaching improbable conclusions about how the world works, it repeatedly defies common sense and provokes widespread rejection of its findings. We now think, for instance, that quantum effects (in particular, the Pauli principle) are responsible for the fact that solid objects occupy space; we know that our planet is a speck of dust at the periphery of a giant galaxy, itself just one of many billions that populate the universe; and we have excellent reasons to believe—contrary to a surprisingly still popular opinion—that human beings are very close relatives of chimpanzees and gorillas. Science proceeds in a way similar to Sherlock Holmes’s explanation to Dr. Watson in “The Adventure of the Beryl Coronet”: “It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.”

Another commonly misunderstood characteristic of science is that it is not in the business of delivering permanent truths, but offers instead provisional conclusions that have a certain probability of being true. So, for instance, when I said in the previous paragraph that we know that our planet orbits around an average star in the suburbs of the Milky Way galaxy, what I meant was that this is the best supported conclusion arising from a myriad of astronomical observations and from our theoretical understanding of planets, stars, and galaxies. It is certainly possible that either the observations or our theories (or even both!) may turn out to be wrong or deeply flawed in some manner, and that future generations of astronomers will look upon us with the same condescending smile that we reserve for Ptolemy’s idea that the earth was the center of the universe and the rest of the cosmos went around it, moved by invisible celestial spheres.

The tentativeness of scientific conclusions is a source of continuous inspiration to scientists, but also of perennial frustration and misunderstandings for policymakers and the general public, all of whom would much rather be told “the Truth” by scientists and be done with it—especially after paying millions of dollars to finance scientific research. And yet there is a profound lesson in humility to bring home here. It is rather ironic that science is often portrayed as the ultimate refuge of the arrogant, but that scientists themselves keep trying to explain to us the limits inherent in the human quest for knowledge about the world (discussed in Chapter 8).

What, then, constitutes science as a distinct field, separate from philosophy, literary criticism, or whatever else? Although a precise definition of science is probably impossible because of the nature of the beast itself, I would say that science is a form of inquiry into the natural world characterized by the continuous refinement of theories that are in one way or another empirically verifiable. It is this unique blend of theorizing and empirical investigation that is at the core of the scientific enterprise. As the philosopher Immanuel Kant (1724–1804) famously put it, “Experience without theory is blind, but theory without experience is mere intellectual play.” If science were just about facts, it would be the same as stamp collecting, but if scientific theories were not continuously checked against empirically verifiable facts (through either experiment or observation), they would quickly degenerate into pseudoscience, the kind of thing we see with astrology, parapsychology, or creationism.

What about philosophy? If science is difficult to define precisely, the task is pretty much hopeless in the case of philosophy, a much older discipline that has evolved along very distinct and sometimes contrasting lines. Broadly speaking, philosophy is traditionally divided into a number of branches that deal with questions concerning the nature of reality (metaphysics), our access to that reality (epistemology), what we ought or ought not to do (ethics), how we should reason (logic), and what is beauty (aesthetics). More recently, the emergence of a spate of new fields—typically labeled “philosophy of science,” “philosophy of mind,” “philosophy of religion,” and so on—has advanced concerns with the philosophical aspects of other disciplines.

One of the most influential philosophers of the twentieth century, Ludwig Wittgenstein (1889–1951), said, “Philosophy is a battle against the bewitchment of our intelligence by means of language,” and that is certainly a good way of looking at what philosophers do. What Wittgenstein meant was that human language is by its nature imprecise and prone to confusion (providing an ever-renewable source of material for comedy, which in turn has seriously been compared to philosophizing) and that we therefore ought to be perennially on guard against being misled by how we use words. Then again, it can also be argued that sophisticated thinking about the world simply cannot be achieved without language, so we seem to be in a bind. The problem is no different, in principle, from the one that scientists encounter in their line of work: every tool they use is by necessity limited and flawed in some respect, and yet they need to use those tools to move forward with their investigations. The difference is that philosophy, in this way of looking at things, deals with the power and limits of the ultimate human tool: language itself. (Incidentally, this is not to say that philosophy reduces to linguistics; to make things even more confusing, you might not be surprised to learn that there is also a philosophy of language.)

Of course, if you asked one hundred philosophers what philosophy is, you would probably receive the proverbial hundred (and one) different answers. And yet, thinking of philosophy as the discipline that deals with the rational use of language seems to me the easiest way to understand why philosophy also is the broadest possible discipline: because it deals with our most basic tool for knowing and communicating things, it in some sense encompasses all of human knowledge. There are plenty of other conceptions of philosophy, but my take on it is that ultimately philosophy is founded on the construction (and deconstruction) of reasoned arguments. Typically, a philosopher will pose herself a set of questions, examine what is known about them, and explicitly reason her way to a particular conclusion. Other philosophers will then examine and pick apart her reasoning and see how it withstands critical scrutiny, probably presenting arguments of their own in favor of a different conclusion. And so on. There are traditions that are commonly counted as philosophy that do not follow this modus operandi—for instance, the so-called Eastern philosophies, and also part of what is today referred to as “continental” philosophy (because it originated with the work of some eighteenth- and nineteenth-century philosophers from continental Europe, such as Immanuel Kant and Friedrich Nietzsche [1844–1900]). What I consider philosophy in this book is the sort of intellectual activity that started out in ancient Greece before Socrates (469–399 BCE) and whose Greek root charmingly translates to “love of wisdom.”

Just as with science, there are several common misconceptions about philosophy, and one definitely needs to be put to rest at the outset: philosophy, like science, does make progress, even though its progress has to be measured differently from scientific progress. Science, roughly speaking, can be said to make progress in proportion to how its understanding of the world matches the way the world actually is. (This idea is a bit simplistic, as any good philosopher of science will tell you, but we will take it as a good enough approximation for our purposes.) For instance, the Copernican theory of the solar system is better than the Ptolemaic one because, as a matter of fact, it really is the sun and not the earth that is at the center of the system. And the Keplerian theory that succeeded the Copernican one is even better, because it comes even closer to reality: Kepler (1571–1630) realized that the planets follow elliptical orbits, not circular ones, as Copernicus (1473–1543) thought, and that the sun is not quite at the center of the whole thing but rather occupies one of the foci of those ellipses.

Analogously, philosophy also makes progress when it understands better and better the meaning and implications of human concepts and how they relate to the world. For instance, philosophers have produced several theories of human morality, exploring a variety of logical possibilities (discussed in Chapter 5). As I have already hinted, Aristotle said that morality is about what makes human beings flourish (so-called virtue ethics); Jeremy Bentham (1748–1832) and John Stuart Mill (1806–1873) in the eighteenth and nineteenth centuries advanced the idea of utilitarianism, according to which what is ethical is whatever increases the happiness of the greatest number of people; and Immanuel Kant, also in the eighteenth century, articulated a view of morality as a set of rules based on certain duties we ought to have with regard to other human beings (a rule-based, or deontological, ethics).

Philosophers have worked out the implications of these and other systems, criticized them, and proposed refinements and alternatives. No philosopher today would be so naive as to espouse any of these ideas in anything like their original form, because discussions in the field have led to more sophisticated versions of them, and indeed, the debate is still moving forward from this new level of understanding.


On Sale
Oct 2, 2012
Page Count
320 pages
Basic Books

Massimo Pigliucci

About the Author

Massimo Pigliucci is the K. D. Irani Professor of Philosophy at the City College of New York. The author or editor of sixteen books, he has been published in the New York Times, the Wall Street Journal, the Washington Post, and Salon, among others. He lives in Brooklyn, New York.  

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