The Relationship between Physics and Philosophy By Kartik Chundru, Laura Byrne, Mark Allen and Tom Ambrose Supervisor: Prof. Stefan Hutzler Introduction Physics and philosophy are two subjects that are often thought as two very disparate subjects, yet they share much common ground, and often they share many thinkers too. In this project, we looked at the ways in which the study of Physics and Philosophy differ, in the ways at which they are similar, and some of the common topics both fields study. In particular, we look at some topics like space and time, determinism and free will, and reality, as well as topics like experimentation in both fields, how they arrive at ‘truth’, the various schools within philosophy, and the origin of the phrase Natural Philosophy itself. Galileo, father of experimental physics. Einstein, revolutionised Physics with his thought experiments Natural Philosophy •The word Physics only came into use around the 19th century. Before this, what we know as Science today was called Natural Philosophy, the attempt to understand and explain the workings of the natural world in a contemplative way. •The mathematical and experiment based science of modern times set in around the 17th and 18th centuries, in what is now called the scientific revolution. Newton’s main scientific work, Philosophiae Naturalis Principia Mathematica, is an example of this revolution in Natural Philosophy. •Remnants of the term Natural Philosophy still remain in physics today. For example, one of the oldest scientific journals still published is called Philosophical Magazine. Also there exists a chair in the School of Physics in Trinity called, the Erasmus Smith's Professor of Natural and Experimental Philosophy, currently held by professor Coey. Common topics of study Matter, Space, and Time What the world is made of is a question that has engaged philosophers too, from the preSocratics to the early modern. The philosopher Thales was one of the first to try describing the world without resorting to supernatural arguments. Atomic theory has its roots in Greek philosophy, indeed the word atom comes from the Greek for ‘indivisible’. Philosophers talk of what ‘substances’ the world is made of. Einstein’s theories of relativity show us that time and space are not independent quantities, and quantum mechanics (QM) tells us that words like wave, particle, position and velocity are meaningless at a certain scale. Determinism and Free Will Objective Reality As physical entities, people are systems of particles, so how The idea of an objective reality, much of our actions are as is what is knowable, is an important topic for both physics governed by the laws of physics? and philosophy. The concept of free will is central to much of philosophy. Are we Descartes set a foundation for free to make our own decisions, knowledge with his “I think or are we simply automata? therefore I am” and worked from there. Many philosophers ascribe special importance to our The Many Worlds interpretation supposed determinism of QM states that we are in just behaviour, while others believe in one world of many, free will. Others claim the two are corresponding to all possible compatible. outcomes. Is this just a mathematical formalism, or does The problem is muddied with the it have deep philosophical Copenhagen interpretation of implications? QM, that states some processes are inherently random. While different schools have different opinions on what we Some physicists, such as Wigner can know, QM states qualitatively and Penrose ascribe special and quantitatively what we importance to the role of cannot know and by how much. consciousness in QM, and vice versa. How do we know what we think we know is true? Physics, philosophy and different schools of thought Philosophy Share many different schools of thought such as Realism, Idealism and Rationalism. The school of thought a philosopher believes in is entirely up to their own opinion Some of the different branches are concerned with topics that have a very large scope such as the issue of what is knowledge (Epistemology), and why something like science is possible. Tend to give more emphasis to a single authors viewpoint rather than to a topic as a whole To educate philosophers they study the (old) writings of other philosophers, these might date back more than 2300 years, as is the case for Aristotle. Physics Share the same school of thought throughout the subject, for example all Physicists believe in the existence of a material world and of things such as matter. It is only for the new and cutting-edge theories that different opinions exist in Physics. Have a sense of unity flowing through their subject, for example there is a set of SI units that are used regardless of what topic of Physics is being studied. Also they agree on a on a set of theories and these theories are used countless times across all areas of Physics This unity and universal agreement within Physics has enabled the subject to use textbooks to educate physicists Physicists generally believe in an objective reality, but at microscopic scales it’s not the reality we’re used to. Experimentation The Schrodingers cat experiment References: History of Western Philosophy, Bertrand Russell Placeholder Text Placeholder Text Placeholder Text Aristotle’s method of reasoning •Aristotle used a deductive logic method to reach conclusions on natural phenomena. •Galileo is considered ‘the father of modern physics’ as he started a long tradition of experimentation, and yet if an experiment would prove him wrong he would dis-regard the results in favour of his own theories. •Einstein used thought experiments in order to comprehend time dilation at the speed of light which he could not truly experiment on. This was a field that held the interest of Physicist and Philosopher alike. •These thought experiments represent a common link between Physics and Philosophy. They are a tradition that goes back all the way to Galileo studying the basic laws of gravity. They allow the scholars of both fields to explore concepts beyond their own physical means. •Social experiments such as product interest groups show that while the idea of physical experimentation is not used in philosophy it has taken hold beyond the Natural Sciences. © School of Physics, Trinity College Dublin