Sara Strandberg, experimental particle physicist at the ATLAS-experiment at CERN
Richard Dawid, theoretical physicist and professor of philosophy of science and philosophy of physics
—Our understanding of the world improved dramatically when we realized that we can do experiments to test a hypothesis. A theory can be the most beautiful ever, but until it has made predictions that have been verified by experiments, it is nothing but a good idea, says Sara Strandberg.
—The best reason to trust a theory is to note that it predicts things we can see with our senses. But there are other arguments that can tell us that a theory has good chances to be correct, says Richard Dawid
The subatomic world
“In particle physics we try to find the smallest building blocks of matter and the forces that act between them. From experiments carried out over the last 100 years we know that atoms are made from protons, neutrons and electrons, and that the protons and neutrons in turn consist of quarks. The quarks are bound together by gluons - the mediators of the strong force - while the electron is bound to the atomic nucleus by photons - the mediators of the electromagnetic force. These particles are all part of the standard model, the prevailing theory to describe the subatomic world.
The elusive dark matter
But we also know that only 4% of the energy content of the universe is made up of atoms. As much as 25% is in the form of dark matter - likely another elementary particle that we have not yet discovered. Many experiments around the world, such as those at CERN's Large Hadron Collider, currently try to find the elusive dark matter particles and learn their true nature.” Sara Strandberg
String theory you have to believe
String theory is one single theory for the explanation of all four known fundamental interactions in our world, gravitation, electromagnetism, strong nuclear force and weak nuclear force. It is used to explain things that can’t be explained by a theory of gravity or a theory about nuclear forces alone. For example it allows you to study the very early stages of the universe. There is only one problem. String theory has not been confirmed by any experiments. As it stands, you just have to believe in it. But how can we trust something that has not been shown to be correct by experiments?
String changed his field
For Richard Dawid that first got a doctoral degree in Physics, the philosophical reflections around this theory eventually became so important that he decided to change field completely. He became a science philosopher instead.
—String theory is so crucial and different…it tells us something about the way science changes once we try to describe all physical phenomena based on one single theory. Looking at those changes from a philosophical perspective can help us to understand their full significance, says Richard Dawid.
About the speakers:
Sara Strandberg main research interest lies in trying to clarify how the current model of the subatomic world, the so called Standard Model of particle physics, can be expanded to better describe our universe. In her research, which is carried out within the ATLAS experiment at the CERN laboratory outside Geneva, she is searching for heavy exotic particles that could explain the origin of the dark matter in the universe.
Richard Dawid holds a PhD in theoretical physics from the University of Vienna. After some years as a physicist at the TU Munich and the Lawrence Berkeley Laboratory, he switched to philosophy in 2000. Dawid’s work focuses on philosophical aspects of contemporary theories in high energy physics and cosmology. Currently, Dawid is leading a VR-funded research project on the philosophy of cosmology. He is the author of the book: String Theory and the Scientific Method.