Stanford historian examines age-old inquiry about what it means to be 'living'

In research covering four centuries of scientific debate, Stanford historian Jessica Riskin investigates different views of man and machine, and how this debate laid the groundwork for later theories of evolution and science.

Jim Block Jessica Riskin portrait

Stanford historian Jessica Riskin explores the decades-old debate of what differentiates humans from machines.

What do human beings and machines have in common?

Stanford historian Jessica Riskin argues that philosophical debates stretching back to the 17th century have profoundly shaped current ideas in the life sciences about what makes a living thing alive – and what makes it act and change.

For centuries, philosophers and scientists have regularly compared living things to machines, but they have meant very different things by the word "machine," according to Riskin, a professor of history who writes about these issues in her new book, The Restless Clock.

Riskin investigates the history of lifelike machines and the philosophical and theological debates surrounding them, and explores how we can better understand the current state of theories of life and sentience in the areas of evolutionary biology, genetics, cybernetics and robotics.

Riskin's project led her through the "clockmakers route" that winds through the mountains of Switzerland. There, she observed working "automata" – moving mechanical figures of people and animals – dating from the 17th, 18th and 19th centuries. These life-like figures encouraged philosophers to understand living things in terms of mechanism and machinery.

Fast forward to the 21st century, and while visiting the artificial intelligence robotics lab at MIT, Riskin observed a strikingly similar approach in evolutionary and behavioral robotics. Seeking to understand humans as machines was not a 20th century development, but dates back to philosophers René Descartes and Gottfreid Wilhelm Leibniz.

Man and machine

The 17th century discussion about men and machines was less concerned with whether humans were machines, and more with what kind of machines they were, she said. Two main ideas of "machine" competed in the 17th century, and each idea led to different conclusions about living things' capacity to act in the world in a self-directed way: that is, their agency.

One idea was that living things were designed machines, works of engineering that simply functioned as they had been designed to function by a "divine engineer" of sorts, Riskin said. For 17th century philosophers, God was this outside force, and the fact that living things worked so well was evidence of God as a rational engineer.

In the course of her research on Leibniz, Riskin uncovered a surprising alternative view about "machines" and, with it, a whole other history of the life sciences. Instead of being moved by outside forces, machines were seen as active and responsive.

Riskin noted a passage from Leibniz, who says that in German, the word for the balance of a clock is unruhe, which she translates as 'restless.' "Clocks, like bodies, had to be perpetually disquiet, always adjusting and responding to things happening outside themselves," she said.

In this alternative tradition in the life sciences, she said, people seek to understand the world in terms of moving parts and machinery, and yet it's a completely different kind of machinery because the parts are active, and the machinery is intrinsically active.

The idea of active machinery supported the notion that living things were not designed all at once, but instead could transform themselves, she said. However, this was a dangerous argument that threatened the idea of God, so it was ultimately cast into the shadows.

Evolution debates

Still, the debate over active and passive machines set the stage for philosophical discussions about emerging theories of evolution, according to Riskin.

Most notable were those of Jean-Baptiste Lamarck, a 19th century biologist, who proposed that an organism could develop inheritable characteristics over its life span. Riskin suggests that the expulsion of Lamarck from mainstream science was due to the threat he posed to the theological notion of an external designer. He actually coined the term "biology" to denote a science of life, she added.

She argues that neo-Darwinism's turn from Lamarck erased the possibility of an organism's agency in the evolutionary process. In a neo-Darwinian model, living organisms are made of dumb, mechanical parts that can only change through random variation and natural selection.

But Riskin challenges such beliefs.

"There are assumptions that are tacitly shared by the members of a discipline like evolutionary biology – such as the conviction that you can't ascribe evolutionary agency to an organism. I want to question those convictions – not as a biologist, but as a historian, by showing their unexpected historical roots," said the history professor.

In the course of her research, Riskin critiqued the evolutionary and cognitive theories of prominent figures such as Richard Dawkins, Daniel Dennett and Stephen Pinker. This scientific tradition, which is generally termed the New Atheism movement, reduces the mind to passive mechanical parts.

A great irony exists in this view, Riskin said "I don't think any of these thinkers and writers realize that the view they are espousing against religious and theological views of nature actually originated as part of a theological program, the argument from design."

In other words, she said, the New Atheists' view of passive living organisms that are unable to shape their own evolutionary destiny, actually originated in theological arguments from design.

On the other hand, the "restless clock" model of living things as active machines capable of transforming and evolving has roots in the work of Leibniz and Lamarck, thinkers who sought a science of life that did not make continual appeals to a supernatural God.

Riskin suggests that understanding the historical context behind these different views of man and machine can help us today in our fast-accelerating technological age.

"It's important to understand the stakes of current debates in science – those stakes often have long histories and you can't understand the stakes without knowing about their histories," she said.