Locality And Causality

Here is the sixty-ninth episode of Quantum Foam, Locality And Causality. The principle of locality states that an object is influenced directly only by its immediate surroundings. A theory that includes the principle of locality is said to be a local theory. This is an alternative to the concept of instantaneous or non-local action at a distance. Action at a distance is the concept that an objects motion can be affected by another object without the 2 being in physical contact. It is the concept of the non-local interaction of objects that are separated in space like Newton's law of universal gravitation. He overturned the Aristotelian ideas that an object has to be in contact with another object in order for them to have an effect on one another. Gravity has an effect on one object and another object when they are in close proximity with one another and when their masses are relatively large. The earth and the moon are connected by gravity. This is locality at its core. Locality evolved out of the field theories of classical physics. The idea is that for a cause at one point to have an effect at another point something in the space between those points must mediate the action. To exert an influence something such as a wave or particle must travel through the space between the 2 points carrying the influence. Locality and causality are related in that they determine whether or not objects have an effect on one another in a general sense. The special theory of relativity limits the maximum speed at which causal influence can travel to the speed of light, denoted as c. Therefore, the principle of locality that in an event at one point cannot cause a truly simultaneous result at another point. What role, if any, do causal notions play in physics? On the one hand, it might appear intuitively obvious that physics aims to provide us with causal knowledge of the world and that causal claims are an integral part of physics. On the other hand, there is an influential philosophical tradition dating back to Ernst Mach and to Bertrand Russell's extremely influential article on the notion of cause from 1912 denying the applicability or at least the usefulness of causal notions in physics. While this tradition is perhaps not as dominate today as it once was, there continues to be a lively and active philosophical debate on whether causal notions can play a legitimate roll in physics, and if yes, what role that might be. This entry surveys the main arguments in this debate focusing in particular on arguments appealing to putatively distinguishing characteristics of theorizing in physics. In discussing the role of causation in physics or in our conception of the world more generally, we may be engaged in several different philosophical projects. While there are obvious points of contact among these projects and a philosophical account may contribute to more than 1 project simultaneously, the 3 projects distinctly have different core aims and are characterized by different methodologies. The aim of the metaphysical project is to uncover the metaphysical grounds or truth makers or causal claims. The main division in the metaphysics of causation is between broadly Humean and Non-Humean accounts of causation. Humean accounts deny the existence of fundamental modalities and maintain that fundamentally the universe is composed of a distribution of categorical properties and relations instantiated by localized entities. This covers the very deep philosophical accounts of causation as it is currently understood in the fields of physics and other related sciences.