Quantum mechanics describes the world in a way which is intimately connected with the process of observation. The equations of quantum mechanics only predict the probability of observing a system with certain physical properties as the outcome of an experimental measurement. They do not specify a) what an observer is, nor b) the properties of a system in between measurements, nor c) how to draw the line between the observed phenomenon (i.e., quantum world) and the observer. What is it, exactly, that causes the collapse of the wave function (describing the superposition of several quantum states) to a single experimental measure? Given the primary role of observation in shaping the physical properties of phenomena, what is the relation between the awareness of conscious observers and the physical world?
As discussed in the previous modules, numerous interpretations of quantum mechanics have been formulated to answer these questions. In the ‘von Neumann–Wigner interpretation’, it is consciousness itself that causes the collapse of the wave function, although most physicists would not be comfortable with such an explanation. According to this interpretation, the experimental devices used to study quantum phenomena are of the same nature as the rest of the physical world. The mind, on the other hand, is described as a non-physical phenomenon existing outside the material universe, with a causal impact on the collapse of the wave function. This view, therefore, assumes a non-physicalist ontology of mind – in other words, that the mind is non-material in nature.
Another possible interpretation is that of QBism (short for ‘Quantum Bayesianism’) which is concerned with epistemology (what we know) more than ontology (what is real). So, rather than trying to define quantum entities objectively, and consider them as inherent, objective facets of the external world, the focus with QBism is on the limited knowledge, actions, and experiences of the observer themselves. It follows that the equations of quantum mechanics are seen to reflect and describe the degrees of belief that an observer has about the possible outcomes of quantum measurements, rather purporting to describe the external reality itself. Accordingly, some have criticized this view as anti-realist, but it is more accurately described as a form of participatory realism, reflecting the important – but not exclusive – part that the observer plays in the quantum system. QBism is related to Copenhagen Interpretations but aims to make them sharper and more consistent.
Conversely, other interpretations of quantum mechanics, such as Carlo Rovelli’s relational interpretation, posit that any physical system itself can be considered as an observer, regardless of its conscious awareness (or lack thereof). This is because even if a physical system is not itself conscious, it still ‘fixes’ the surroundings of a quantum system in a particular way, such that the quantum system must behave consistently in relation to those defined surroundings.
Understanding the relationship between consciousness and the physical world might help to explain why mental processes are so strongly correlated with physical changes in the brain. Is the mind completely reducible to neuronal activity, or does it have a causal influence on the physical processes taking place in the brain? Drawing on their expertise in quantum mechanics and Buddhist philosophy, in this module, Geshe Tenzin Namdak and Prof. Carlo Rovelli discuss the nature of the self, the interaction between consciousness and physical reality, and the relation between the mind and the brain.
Is there a fundamental level of reality? This lesson contrasts the views of reality put forward by different philosophical systems and discusses parallels between consciousness, as seen by the Yogācāra school, and the observer in quantum mechanics, before investigating the nature of the mind as seen through Buddhist Philosophy.
Some interpretations of quantum mechanics (such as von Neuman-Wigner’s and QBism) assert the crucial importance of conscious observers. Prof. Carlo Rovelli, on the other hand, tried to formulate an interpretation which could disentangle the complexities of quantum mechanics from the complexities of consciousness. His hope, in doing so, was to bring some clarity on the nature of quantum phenomena as being something independent from human consciousness. This relational interpretation does not confer a superior role to human consciousness: any physical system can be the ‘observer’ relative to which the properties of another physical system emerge. In this lesson we will explore if this relational interpretation can help reconcile the scientific understanding with our 1st-person, lived experience of the mind.
We recommend reading the lecture notes before you start watching the content. This will help you to start contemplating some of the topics before you begin to watch the lecture.