Big Ideas Courses
- Spring 2013

Letters & Science 122    Readings

Raphael Bousso (Physics)
Hubert Dreyfus (Philosophy)
Sean Kelly (Harvard University)

Tuesday and Thursday 2:00-3:30, 220 Wheeler Hall, ccn: 52013 - 4 Units

Students with solid experience in math, such as an AP math course in high school or a math course in college, will be most likely to succeed in this course.

Augustine said, famously, that he always thought he understood what time was until he started thinking about it.  That was when he realized he had no idea.  This course will address various aspects of the nature of time, including the way we experience it, the way it organizes our everyday world, and the way it stands – if it does – at the foundation of the physical universe.

I – The experience of time [Sean Kelly]

Philosophers have noticed for a long time that there is a difference between the question whether two things happen at the same time, and the question whether I experience them to happen at the same time.  If two bells ring 50 ms apart, then they are not simultaneous.  But I might nevertheless hear them as being simultaneous.  The features of time therefore – what it is for things to have a duration, to occur at the same time, to occur before or after one another – are not the same as the features of the experience of time.  Philosophers from Locke and Hume to Kant, Husserl, Bergson, and William James have asked questions about what the phenomenological features of the experience of time are, and about what kind of being I must be in order to experience them that way.  This section will explore those thinkers and the questions they ask.

II – World time [Hubert Dreyfus]

The role time plays in our lives is not restricted to the experiences we have of it; it is not only what Kant called “an inner sense.”  There is also a public, pragmatic understanding of time that structures the world of our everyday activities.  For example: “Now that we have finished breakfast, it’s time to go to work.”  The public, pragmatic understanding of time is reducible neither to our experience of time nor to the time of the physical universe.  Martin Heidegger finds in this shared and practical understanding of time the organizing principle of our everyday world.

III – Physical Time [Raphael Bousso]

In physics, time can be defined as what a clock measures.  Already at this level, time is a nontrivial concept: different amounts of time elapse on two clocks that part, follow different paths, and rejoin.  Einstein's theories of relativity, the first great triumphs of twentieth-century physics, allow us to compute what any clock will measure.  Yet, the notion of curved, dynamical spacetime as a fundamental dynamical quantity must break down at short distances, when quantum mechanics, the second pillar of physics, becomes important.  This leads to a fascinating conflict, which plays out in the present attempts to unify the framework of physics into a theory of quantum gravity.  Quantum mechanics treats time as a fundamental evolution parameter, yet the study of black holes and cosmology indicates that time is no more fundamental than conductivity, pressure, and other emergent concepts.  The question of whether time is fundamental or not is thus tied to one of the deepest questions in fundamental science: will quantum mechanics survive unification with gravity, or will it prove an approximate framework like every other theory before it?  Time permitting, the mystery of the thermodynamic arrow of time (the increase of disorder in the universe) will also be discussed.

The discussion in the course will be devoted both to understanding, and to understanding the relations among, these three aspects of temporality.

Created November 30, 2012