Theory and Reality

An Introduction to the Philosophy of Science, Second Edition

Peter Godfrey-Smith

• Publisher: University of Chicago Press
• Year: 2021
• ISBN:
  9780226771137
• Topic: Philosophie
• Subtopic: Histoire et théorie de la philosophie

How does science work? Does it tell us what the world is "really" like? What makes it different from other ways of understanding the universe? In Theory and Reality, Peter Godfrey-Smith addresses these questions by taking the reader on a grand tour of more than a hundred years of debate about science. The result is a completely accessible introduction to the main themes of the philosophy of science. Examples and asides engage the beginning student, a glossary of terms explains key concepts, and suggestions for further reading are included at the end of each chapter.Like no other text in this field, Theory and Reality combines a survey of recent history of the philosophy of science with current key debates that any beginning scholar or critical reader can follow. The second edition is thoroughly updated and expanded by the author with a new chapter on truth, simplicity, and models in science.

Chapter 1

Introduction

1.1 Setting Out

1.2 The Scope of the Investigation

1.3 What Kind of Theory?

1.4 Three Answers, or Pieces of an Answer

1.5 A Sketch of the Scientific Revolution and What Came Afterward

Further Reading and Notes

1.1 Setting Out

This book is an introduction to a collection of ongoing debates about the nature of science—how it works, what it achieves, and what (if anything) makes science different from other ways of investigating the world. Most of the ideas we will examine fall into the field called “philosophy of science,” but we will also spend a good deal of time looking at ideas developed by historians, sociologists, psychologists, and others.

The book is organized mostly as a historical narrative that covers a little over one hundred years, from the early twentieth century to early twenty-first. Ideas will be discussed in roughly the order in which they appeared, especially in the first half of the book. Why is it best to start with older ideas and work through to the present? One reason is that the historical development of ideas about the nature and workings of science is itself an interesting topic. I also think that this is the best way to come to understand many of the debates going on now. The main narrative of the book begins in the early years of the previous century. That might seem to be starting a long way back. But I think that if we start there, the story does make sense. If we start later, you are likely to find yourself wondering: why are people setting the issues up like that? A good way to understand the maze of options and opinions in the field is to trace the path that brought us to the state in which we find ourselves now.

The book will tell a historical story and use that to understand debates about science, but my aim is not just to introduce all the different views people have had. I will often take sides as we go along, trying to indicate which developments were wrong turns and which were closer to the right track.

Philosophy is an attempt to ask and answer some very basic questions about the universe and our place within it. These questions can sometimes seem far removed from practical concerns. But the debates covered in this book are not of that kind. Though these debates are connected to the most abstract questions about thought, knowledge, language, and reality, they have turned out to have an importance that extends well beyond philosophy. They have made a difference to many other academic fields, and some of the debates have reverberated much further, affecting discussions of education, medicine, and the proper place of science in democratic societies.

In fact, throughout much of the period covered in this book, all the fields concerned with the nature of science went on something of a roller-coaster ride. Especially in the later twentieth century, some people thought that work in the history, philosophy, and sociology of science had shown that science does not deserve the dominating role it has acquired in Western cultures. They thought that a set of convenient myths about the trustworthiness and superiority of mainstream science had been thoroughly undermined. Others disagreed, of course, and the resulting debates swirled across the intellectual scene, frequently entering political discussion as well. From time to time, scientific work itself was affected, especially in the social sciences. These debates came to be known as the “science wars,” a phrase that conveys a sense of how heated things became.

The science wars eventually cooled down, but there is still a great deal of disagreement about even the most basic questions concerning the nature and status of scientific knowledge. These disagreements often do not have much influence on the day-to-day practice of science, but sometimes they do. And they have great importance for discussions of human knowledge, cultural change, intellectual freedom, and our overall place in the universe. This book aims to introduce you to this remarkable series of debates, and to give you an understanding of the present situation.

1.2 The Scope of the Investigation

If we want to understand how science works, it seems that the first thing we need to do is work out what exactly we are trying to explain. Where does science begin and end? Which kinds of activity count as “science”?

Unfortunately, this is not something we can settle in advance. There is a lot of disagreement about what counts as science, and these disagreements are connected to all the other issues discussed in this book.

There is consensus about some central cases. People often think of physics as the purest example of science. Certainly physics has had a heroic history and a central role in the development of modern science as a whole. Biology, on the other hand, is probably the science that has developed most rapidly and impressively during recent years.

These seem to be central examples of science, though even here we encounter hints of controversy. A few have suggested that theoretical physics is becoming less scientific than it used to be, as it is evolving into an esoteric, mathematical model–building exercise that has little contact with the real world (Horgan 1996). And biology has recently acquired connections with business and industry that make it, in the eyes of some, a less exemplary science than it once was. Still, examples such as these give us a natural starting point. The work done by physicists and biologists when they test hypotheses is science. And playing a violin, no matter how well one plays, is not doing science. But in the area between these clear cases, disagreement reigns.

At one time the classification of economics and psychology as sciences was controversial. Those fields have now settled into a scientific status. (Economics retains an amusing qualifier; it is sometimes called “the dismal science,” a phrase due to Thomas Carlyle.) There is still a much-debated border region, however, and this includes areas like anthropology and sociology. At Stanford University, during the time I was working there on the first edition of this book, a debate over the boundaries of science was part of a process in which the Department of Anthropology split into two separate departments. Is anthropology, the general study of humankind, a fully scientific discipline that should be closely linked to biology, or is it a more “interpretive” enterprise that should be more closely connected to the humanities? After nine years apart, the two Stanford departments reunited. But anthropology is still one of the most fought-over grounds. In 2010 the American Anthropological Association released a new version of their summary of what the field is, dropping the word “science” from the central place it had in earlier statements. The result was uproar and controversy, with an eventual compromise.

The existence of this gray area should not be surprising, because the word “science” is a loaded and rhetorically powerful one. People often find it a useful tactic to describe work in a borderline area as “scientific” or as “unscientific.” Some will call a field scientific to suggest that it uses rigorous methods and delivers results we should trust. Less often, but occasionally, a person might describe an investigation as scientific in order to say something negative about it—to suggest that it is dehumanizing, perhaps. (The term “scientistic” is more often used when a negative impression is to be conveyed.) Because the words “science” and “scientific” have these rhetorical uses, we should not be surprised that people constantly argue back and forth about which kinds of intellectual work count as science.

The history of the term “science” is also relevant here. Our familiar ways of using the words “science” and “scientist” developed quite recently. The word “science” is derived from the Latin word “scientia.” This translates roughly as knowledge, but it referred particularly to the results of logical demonstrations that reveal general and necessary truths. Scientia could be gained in various fields, but the kind of proof involved was what we would now mostly associate with mathematics and geometry. Around the seventeenth century, when what we now call the Scientific Revolution was taking place, many fields we would now describe as science were usually called “natural philosophy” (physics, astronomy, and other inquiries into the causes of things) or “natural history” (botany, zoology, and other descriptions of the contents of the world). Over time, the term “science” came to be used for work with closer links to observation and experiment, and the association between science and an ideal of conclusive proof receded. Scientific knowledge, in this newer conception, can be reliable without being provable and certain. The accompanying term “scientist” was coined by William Whewell in the nineteenth century. Given the rhetorical load carried by the word “science,” we should not expect to be able to lay down, here in chapter 1, an agreed-on list of what is included in science and what is not. At least for now, we will let the gray area remain gray.

A further complication comes from the fact that philosophical theories (and others) often differ in how broadly they conceive of science. Some writers use terms like “science” or “scientific” for any work that assesses ideas and solves problems in a way guided by observational evidence. In this broad sense, science is a basic human activity found in all cultures. There are also views that construe science more narrowly, seeing it as a cultural phenomenon that is localized in space and time. For views of this kind, it was only the Scientific Revolution of the seventeenth century in Europe that gave us science in the full sense. Before that, we find “roots” or precursors of science—work that was often very impressive but different from science itself.

To set things up this second way is to see science as unlike, in many ways, the kinds of investigation and knowledge that routinely go along with farming, architecture, and other kinds of technology. A view like this need not claim that people in nonscientific cultures must be ignorant or irrational; the idea is that in order to understand science, we need to distinguish it from other kinds of investigation of the world. We need to work out why this approach to knowledge, developed by a small group of Europeans, turned out to have such dramatic consequences for humanity.

As we move from theory to theory in this book, we will find some people construing science broadly and others more narrowly. This does not stop us from outlining, here in the first chapter, what kind of understanding we would eventually like to have. However we choose to use the word “science,” in the end we should try to develop both:

1. 1. a general understanding of how humans gain knowledge of the world around them, and
2. 2. an understanding of what makes the work descended from the Scientific Revolution different—if it really is different—from other kinds of investigation of the world.

We will move back and forth between these two kinds of questions throughout the book.

Before leaving this topic, there is one other possibility that should be mentioned. How confident should we be that all the work we call “science,” even in the narrower sense described above, has much in common? One of the hazards of philosophy is the temptation to come up with theories that are too broad and sweeping. “Theories of science” need to be scrutinized with this problem in mind.

1.3 What Kind of Theory?

This book is an introduction to the philosophy of science. But much of the book focuses on one set of issues in that large field. These questions are about knowledge, evidence, and rationality. For example, how is it possible for observations to provide evidence for a scientific theory? Can we ever be confident that we are learning how the world really works? Is there a reason to prefer simple theories over more complex ones? Questions like these fall into the part of philosophy known as epistemology. Philosophy of science also overlaps with other parts of philosophy—philosophy of language, philosophy of mathematics, philosophy of mind, and metaphysics, a part of philosophy that is especially controversial and that deals with the most general questions about the nature of reality itself.

Questions about rationality and evidence—the ones that will often be central in this book—are connected to questions about the authority of science. Do we have reason to rely on scientific work when we have to make decisions about what to do to solve a practical problem—an environmental problem, for example? Those problems about the authority of science are especially pressing, but puzzles about the authority of science arise even before we raise questions about the use of science in policy decisions. I’ll introduce what I mean with an example. Nearly all human cells (and the cells of other animals, plants, and many unicellular organisms) contain mitochondria. These are little structures, with their own membranes around them, that contribute energy to the cell. They are often described as “the cell’s powerhouses” or in similar terms. When I was a student, especially as a result of the work of Lynn Margulis, there was a lot of discussion of the surprising hypothesis that these parts of our cells are descended from free-living bacteria. The idea is that some bacterial cells (or just one) were swallowed in the distant past by another unicellular organism, and our mitochondria-carrying cells today are all descended from that arrangement. This was initially a very speculative possibility that had first been raised in the late nineteenth and early twentieth centuries (before people had a clear picture of what mitochondria were like) by Richard Altmann and others. Margulis defended the idea with new evidence in a 1967 article. After much controversy, during the mid- and late 1980s the idea finally became widely accepted, and it is now in the textbooks.

It may be in the textbooks, but if you press a biologist about an idea like this, you might encounter a fair bit of uncertainty about the right way to express what has been learned. The biologist might say something like this: “That theory has now been established, especially by genetic evidence. It has been shown that mitochondria are descended from free-living bacteria.” But you might hear something different, either instead or as well. The biologist might reflect for a moment and say: “Well, all science is entirely provisional. Nothing of any importance is ever conclusively shown. This theory about mitochondria is the best one we have right now, but one day it might be overturned.” After all, can we ever really be sure about something that was supposed to have happened over one and a half billion years ago?

Scientists often find it difficult to say what it means when a theory has made a transition from being a mere speculation to something routinely taught and assumed in other work. If someone says, “This has been shown,” that often seems too strong—too unqualified. But if they say, “This is just what we’re working with for now,” that often seems to understate things. The situation often seems to be something between those two. There are lots of ways of saying something in between; we might say the theory is well supported, or that it has been confirmed by evidence. But when philosophers and scientists have tried to say what support is, and how we might know when a theory has it, the results have often been frustrating. Problems of this kind have long been central to philosophy of science and will be a central thread running through this book.

Something else you will encounter in this book is a lot of disagreement about what kind of theory we should be looking for. A possibility that might come immediately to mind is that we should look for a theory about scientific thinking. Many philosophers have rejected this idea, though, saying that we should seek a logical theory of science. You might not be sure what sort of thing a “logical” theory is. A lot of professional logicians are not sure either. But roughly, the idea is that we might think of a scientific theory as a set of interrelated sentences that make claims about some part of the world (or perhaps just about our experiences). The philosopher might aim to give a description of the relationships that exist between different parts of the theory, and the relationships between the theory and various kinds of evidence we might find–evidence that might support the theory or clash with it. The philosopher might also try to give a description of the logical relationships that can be found between one theory and another.

Philosophers taking this approach tend to be enthusiastic about the tools of mathematical logic. They prize the rigor of their work. This kind of philosophy has often also prompted frustration in people working on the history of science or on how scientific institutions actually operate: the crusty old philosophers seem to be deliberately removing their work from any contact with science as it is actually conducted, perhaps in order to hang on to a set of myths about the perfect rationality of the scientific enterprise. Or perhaps the philosophers want to be sure that nothing too messy will interfere with the endless intellectual games that can b...