Why Do You Remember The Past But Not The Future?

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The laws of physics don’t specify an arrow of time - they don’t distinguish the past from the future. The equations we use to describe how things evolve forward in time also perfectly describe their evolution backwards in time. So the brain is a thing ruled by the laws of physics - why does the brain and the conscious experience that emerges from it, see the arrow of time so clearly? In other words why do we remember the past and not the future?

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Hosted by Matt O'Dowd
Written by Matt O'Dowd
Graphics by Leonardo Scholzer, Yago Ballarini, Pedro Osinski & Adriano Leal
Directed by: Andrew Kornhaber
Assistant Producer: Setare Gholipour
Executive Producers: Eric Brown & Andrew Kornhaber

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[LexBrown]

I really love clicking on these videos and thinking I’m going to understand. Gets me every time.

[markdelagasse]

Thank you Matt. I am 76 YO and a disabled combat veteran. Life could get very boring. But with your very fine program I have much to think about and life is interesting again!

[orinrin]

"lets imagine the brain as a perfect sphere"
yes. completely smooth

[pinkninja]

Perfect timing! I was thinking about this a couple days from now!

[ryangoodwin]

“The future has already happened, it just hasn’t happened yet.”

[floood]

If you play this video in reverse, you'll remember the future.

[raghuveer]

“Brains aren’t rocks, despite similarities in some cases”

And I took that personally

[freakinschweeet]

It's wonderful that the energy put into creating his heat death t-shirt contributed to the acceleration of heat death itself.

[objective_psychology]

I love how this implies that the universe as a whole does “know” its own future, at least in a classical model.

[oxenfree]

Me: **minding my own business**
PBS Space Time: "Would you like us to educate you into an existential crisis?"

[superuser]

1:32 Matt's memory is so good he even remembers when he was Gabe!

[dakshbansal]

Sometimes the physics gets so advanced it feels like philosophy
“Why we remember the past but not the future?”

[baa]

"Obviously our brains aren't rocks, despite the similarity in some cases..." when I'm watching Space Time, my brain is usually a rock.

[samcrossley]

As a researcher who studies asteroid geology, I appreciate the custom-tailored metaphor.

[thecomprehensionhub]

"Time's fun when you're having flies"
-Kermit Trismegistus The Frog

[winstonknowitall]

I'm not so sure about all this past/future remembering. For instance: I don't remember a word of what you just said, but I remember clearly how confused I felt right after the next episode, which is still in the future.

[akibshamshad]

He - forget the rock let's go simpler (starts explaining quantum physics)
Me - I'm good with rock

[olivercharles]

I am actually surprised, this is one of the few episodes that I seem to mostly understand/get. Thought provoking stuff in this one!

[Desertphile]

My question: how do we humans know if we experience time "forward" or "backwards?" If we pass "backward, " how would we know? It seems to be that no matter what direction time is going, we will always perceive it as going "forward."

[proverbalizer]

I can remember the future, but I usually only remember that I can remember the future when I am having intense and vivid deja vu in the present