---
created_at: '2017-01-07T02:37:53.000Z'
title: What If Time Really Exists? (2008)
url: https://arxiv.org/abs/0811.3772
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[Source](https://arxiv.org/abs/0811.3772 "Permalink to [0811.3772] What if Time Really Exists?")

# [0811.3772] What if Time Really Exists?

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# General Relativity and Quantum Cosmology

# Title: What if Time Really Exists?

Authors: [Sean M. Carroll][32]

(Submitted on 23 Nov 2008)

> Abstract: Despite the obvious utility of the concept, it has often been argued that time does not exist. I take the opposite perspective: let's imagine that time does exist, and the universe is described by a quantum state obeying ordinary time-dependent quantum mechanics. Reconciling this simple picture with the known facts about our universe turns out to be a non-trivial task, but by taking it seriously we can infer deep facts about the fundamental nature of reality. The arrow of time finds a plausible explanation in a "Heraclitean universe," described by a quantum state eternally evolving in an infinite-dimensional Hilbert space. 

| ----- |
|  Comments:  |  Submission to the Foundational Questions Institute Essay Competition on "The Nature of Time." |  
|  Subjects:  |  General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th) |  
|  Cite as:  |  [arXiv:0811.3772][33] [gr-qc] |  
|    |  (or [arXiv:0811.3772v1][34] [gr-qc] for this version) | 

## Submission history

From: Sean Carroll [[view email][35]]   
[**v1]** Sun, 23 Nov 2008 21:07:47 GMT (33kb,D)  

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