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The Unity of Science: A Conversation with Irwin Shapiro

In The Unity of Science: Exploring Our Universe, from the Big Bang to the Twenty-First Century, Irwin Shapiro provides a broad and entertaining survey of major scientific discoveries that have changed our views of nature and, in turn, spawned us to ask further questions.

In this Q&A, we talk with the author about the Harvard course that inspired the book, what we know about extraterrestrial life, and the importance of scientific knowledge being available in popular form.


The Unity of Science is the name of a class you created at Harvard University over a decade ago. What insights from the course shaped your writing process?

IS: I based the book on the material included in the course. Most importantly, I tried to convey the idea that science is the way we describe our knowledge of how the world works and is based on the evidence we gather from observations and experiments. The evidence is critical. The models we develop of the way the world works must be consistent with that evidence to be viable representations of the working of the world.

The book is organized into three themes–the unveiling of the universe, the earth and its fossils, and the story of life. What exactly is the unity of science, and how does it relate to the structure of the book?

IS: The unity of science does not have a precise definition. It is more a concept with many aspects. The basic point is that there is one world and science applies to all of it; we develop models of how this world works, based on our observations and experiments. For convenience, we break science into different types, each of which embodies a (somewhat) different class of phenomena, such as astronomy, biology, chemistry, and physics. Yet they are all united in showing different aspects of one world. The people who study science usually specialize in one or another of these classes, sometimes more than one and sometimes switching from one to another. The structure of the book, its three main parts, together illustrate one aspect of the unity of science; collectively, they involve a major part of the whole of science.

You emphasize the importance of asking good questions and ask readers to view science as a detective story. Why will the Unity of Science appeal to a popular audience, instilling an appreciation for science in readers?

IS: Because of its broad coverage of so many different areas of science, this book should give its readers a good background on our models of how a lot of the world works. With its detective story approach to many important discoveries in different branches of science, the book should appeal to a wide swath of readers among the general public and provide them, as well, with an appreciation of the amazing advances made by humans in the development of science over a relatively brief period.

Can you give an example of one of the amazing advances made by humans in the development of science? And how does this example demonstrate the unity of science?

IS: One of the most important discoveries of science discussed in the book is that of the cosmic microwave background radiation in 1965. These radio waves were discovered to impinge on the earth from all directions at almost identical rates. This discovery gave very strong evidence to support the concept of the Big Bang and provided thereby the first powerful observations relating to the origin of the universe. The experimental and observational results that followed after that initial discovery demonstrate various aspects of the unity of science.

Recently, testimonials at the congressional hearing on Unidentified Anomalous Phenomena (UAPs, otherwise known as UFOs) sparked national interest in extraterrestrial life and intelligence. From a scientific perspective, what do we really know about extraterrestrial life?

IS: Alas, as of now, we do not have any evidence that extraterrestrial life exists. We only have the enormity of the number of systems that there are in the known universe which have conditions similar to earth’s. These are thus possible candidates for life to have developed on them. We have detectors that should be sensitive to characteristics of life, such as might occur with advanced civilizations that have developed devices like ours, or even far more advanced ones, and be able to transmit signals which we could detect. There are also chemicals that might indicate the presence of life, and that we on earth might detect on distant bodies. In fact, we might well be the first human generation to make a strong case for the existence of life outside earth. It is also possible that we could detect signals sent by advanced life elsewhere. Further, it is certainly conceivable that visitors could come from elsewhere or that goods manufactured elsewhere could reach and be detected by us.

What is the greatest threat to popular scientific knowledge today? How does The Unity of Science equip the concerned citizen or amateur scientist to approach misinformation?

IS: The greatest threat to popular knowledge of science is, I suspect, the lack of sufficient exposure of the populace to the importance of science in their every day lives and its relatively easy availability through books such as The Unity of Science. As this book emphasizes, one must be sure that the evidence supporting conclusions on scientific matters is well established. One must, of course, always be on the lookout for scams and learn how to recognize their characteristics to avoid being fooled by willful attempts to misinform people.

Science will likely play an even larger role in our lives as time unfolds and it behooves citizens to understand it at least at a basic level through reading, developing their critical thinking skills, and keeping in mind the importance of reliable evidence when forming opinions on scientific matters.


Irwin Shapiro is Timken University Professor at Harvard University, where he directed the Harvard–Smithsonian Center for Astrophysics from 1983 through mid-2004. Shapiro has received numerous awards, including the 2013 Einstein Prize from the American Physical Society. He grew up in Far Rockaway, NY, and lives in Lexington, MA.


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