Why is it that we can see these multiple histories play out on the quantum scale, and why do lose sight of them on our macroscopic scale?

Many physicists believe that the answer lies in a process known as quantum decoherence.

Does conscious observation of a quantum system cause the wavefunction to collapse? The upshot is that more and more physicists think that consciousness – and even measurement – doesn’t directly cause wavefunction collapse.

In fact probably there IS no clear Heisenberg cut. The collapse itself may be an illusion, and the alternate histories that the wavefunction represents may continue forever. The question then becomes: why is it that we can see these multiple histories play out on the quantum scale, and why do lose sight of them on our macroscopic scale? Many physicists believe that the answer lies in a process known as quantum decoherence. 

It’s not surprising that the profound weirdness of the quantum world has inspired some outlandish explanations – nor that these have strayed into the realm of what we might call mysticism.

One particularly pervasive notion is the idea that consciousness can directly influence quantum systems – and so influence reality.

PBS Space Time examines where this idea comes from, and whether quantum theory really supports it. 

Lex Fridman interviews Sean Carroll in this thought provoking interview.

Sean Carroll is a theoretical physicist at Caltech and Santa Fe Institute specializing in quantum mechanics, arrow of time, cosmology, and gravitation. He is the author of several popular books including his latest on quantum mechanics (Something Deeply Hidden) and is a host of a great podcast called Mindscape. This conversation is part of the Artificial Intelligence podcast.

This is the second time Sean has been on the podcast. You can watch the first time here: https://www.youtube.com/watch?v=l-NJrvyRo0c