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Comment by fluoridation | Hacker News Reader

Can the universe read your mind? If it can, then the universe need not be larger than your own mind plus some comparatively small constant. When you're done reading this sentence and focus back to "Hello" you'll notice that its appearance and location are consistent with what was on your mind, so it's possible that there's some machinery reconstructing the previous state of what you were perceiving so it matches your memory.

If it can't read your mind then the universe external to it must necessarily be much larger, since it can consistently hold much more information than you're able to recall.

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You bring up the concept of time.

But is there a proof that time exists?

I can "remember" something, but that act of "remembering" is happening in the now. I don't know if there really was a past.

When I look at "Hello", I don't remember something at the same time. The shape of the four "Hello" letters are all I can hold in my mind. So from that perspective, "Hello" might be all there is and all there has ever been.

Is there even a "now"? Our neurons add milliseconds to every signal impulse that allows us to experience the "now" (that's not to mention the time it takes for the brain to process everything). We're perpetually experiencing the past whilst moving through space.

It doesn't matter. The fact that you're able to compare the Hello on your "screen" to the Hello in your "memory" should prove to you that there's at least two of them. A computer can't distinguish if it has started running in the middle of a computation with its registers and memory arbitrarily filled with values, but it can still arrive at results based on those values. Likewise someone might very patiently turn a computer on and off while each time filling its memory and registers with data that would be consistent with the equivalent computation as if it had been running each step of the way. That would mean whoever is doing that needs to hold at least as much state as would be necessary to execute the computation normally.

When I compare the "Hello" on the screen to the concept of "Hello" in my mind, I cannot hold the details of the character shapes in the same clearity as I do when I just focus on the shapes.

So the siutation with the two Hello's might be just as simple (My rough estimation: 100 bits) as the situation where I focus on the shapes.

That's why my feeling is that the lower bound for how complex the universe is, is 100 bits.

Let k be the fraction of the information contained in the original perception that you're able to hold in your mind. Regardless of how large k is, the universe maintains apparent consistency to the subjective observer, so its intermediate states between when you observe it and when you observe it again must be held somewhere, be it in the configuration of particles in a physical universe, or the memory storage of some mad scientist who keeps your brain in a vat and feeds it fabricated data. If the universe consisted solely of whatever it is you're perceiving or contemplating at any given time your thoughts and perceptions would not make sense to you, because there would be no consistency from one moment to the next. You would look at Hello, look away, look again, and see Bye. Even if time is an illusion and you only looked the second time, you would need to account for the fact that your false memory of a moment that never existed matches the perception that you're processing now.

I don't see any proof that time exists. For all I can tell, only the present moment exists. You say I "observe it again". But how do I know I observed something in the past? The memory is just an experience I have in the present moment.

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