Illinois philosophy professor and Brand Fortner Faculty Scholar in Physics Christopher Weaver recently published his second book, Causation in Physics. Philosophers of physics have long debated the role of causation. Weaver argues that causation not only exists in fundamental physics but that it is essential to it.

Weaver says he first became interested in the philosophy of physics when he realized that good philosophical reflection upon the nature of the world must be empirically informed, and that sound physics provides the most reliable and successful empirical access to the physical world. 

Weaver explains, “My interest in the history and foundations of physics naturally emerged from my investigations into questions in the philosophy of religion, epistemology, and metaphysics, such as: Did the universe begin to exist? What is the nature of scientific knowledge? Is simplicity, elegance, or beauty a guide to scientific truth and if so, why? What is the nature of space-time?”

In his new book, Weaver enters a longstanding debate within the philosophy of physics. He says, “Today, most contemporary philosophers of physics believe that there is no causation in physics. Some members of this community have added that as physics developed, becoming more and more mathematically sophisticated and rigorous, causation and causal talk dropped out of view. I disagree with the modern consensus and challenge its understanding of the historical development of physics. 

“Leaning on the experimental realist tradition, I show that causation is central to our best physics, because the causal potency of even microphysical systems constitutes the means whereby experimental physicists detect them and subsequently exploit knowledge of them to secure technological innovations.”

According to Weaver, the arguments against causation in physics typically fall into three categories, “the argument from time-reversal invariance, the argument from bidirectionality, and the argument from locality.” In his new book, Weaver responds to each of these arguments, positing that causation is indispensable to our best fundamental physical theories.

Causation in Physics is available free of charge through open-access publication, which was made possible by the funding Weaver received as the inaugural Brand Fortner Faculty Scholar. 

Weaver says his affiliate appointment at Illinois Physics has enhanced his research though the connections he now enjoys with Illinois Physics faculty members. He says, “I have been the beneficiary of numerous discussions with physicists about various aspects of my research. I have even visited the Materials Research Laboratory to learn about X-ray Photoelectron Spectroscopy (XPS). Every single person has been helpful and encouraging. I couldn’t be happier with the support I have received.” 

Weaver is currently working on his third book project entitled The Arrow of Time: An Inquiry into the Foundations of Boltzmannian Statistical Mechanics, which is under contract with Routledge Publishing, for inclusion in the Routledge Studies in the Philosophy of Mathematics and Physics series. 

Editor's Note: This story was originally published on the Illinois Center for Advanced Studies of the Universe website.