An intermediate understanding of Quantum Mechanics

This post was adapted from a Twitter thread. Yeah.

I’ve been reading Sean Carroll’s new book and feeling inspired, so here’s a short commentary on QM from an excited amateur.

For a long time now, I’ve looked at QM as trying to answer the question “if existence were possible, how could we describe it?”

This question requires careful analysis of existence itself. That’s why it’s elegant: it starts at the fundamental distinction between something and nothing.

The interesting thing to me is that if you start doing thought experiments that start with an empty universe and then introduce “somethings” into it, you quickly realize a need for defining space and time. In other words, space and time emerge from a barebones reality.

This is something I’ve convinced myself of, and have been living with for a while. I’m almost at the part of the book where Carroll talks about emerging spacetime, and I can’t wait to study how he talks about it.

For now, the story I tell myself is that the simple fact that two somethings could be distinct, gives rise to the notion of space. And the simple fact that things change, gives rise to the notion of time.

This means that things first have to exist for space and time to have meaning. I.e. Spacetime emerges from “information”.

Closing thought: I think Many-Worlds and QBism are manifestations of epistemological dualism. QBism is the solipsistic perspective, and Many-Worlds is the, um, other one. I don’t know what the appropriate dualist counterpart of solipsism is. Empericism? Naive realism? :P