Philosophy of Spacetime

• 129: What is the real nature of spacetime and gravity?

• What is its ontology? Spacetime as a fundamental entity?

• Or is spacetime replaced by something else?• Approaches: strings, loops, bottom-up…

• Common feature: spacetime/gravity emerge!

• Hooke’s law for a polymer in a heat bath:• No microscopic force.

• Could gravity emerge? (E. Verlinde)

Sebastian De Haro (AUC/UvA)

Emergent Spacetime and Dualities• ’t Hooft: the holographic principle: a gravitational theory

in a region of space is equivalent to a quantum theory, without gravity, on the surface bounding this region.

• Important conceptual questions (physical/found./phil.):• Does spacetime emerge? What does ‘emergence’ mean?

• What picture of space, time and gravity can we get from our best theories?

• Gravitons? As opposed to gravitational waves? • Or just dual theories?

An Interdisciplinary Research

• Use of these concepts (emergence, duality…) in the literature is muddled: conceptual analysis needed.

• Duality relates to important philosophical questions: • Individuation: when are two theories ‘the same’?• Ontology: when are two theories about the same subject matter?• New insights on reductionism and emergence, much (and, often, confusingly!)

debated in the literature.

• Foundations of space and time: a very Dutch topic going back to Lorentz! • Many of these issues (ontology and emergence of spacetime…) relate directly to the

“big questions” submitted by the public.• Opportunity for broad collaboration between physicists (over all ranges of energies!),

philosophers, outreach!