Comment by freedomben | Hacker News Reader

Comment by freedomben | Hacker News Reader

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Yes you can sometimes do that (I've lucid dreamed quite a few times before and it's pretty wild), but it's nowhere near 100% reliable. you can get pretty good with practice, but even then it's not a scientific test. It's more of a process of reasoning and gut checking. The human mind can fill in an incredible amount of detail when needed. In one lucid dream I was playing a song on the guitar that I had (as far as I know) never heard before (myself in the dream was inventing the song). I realized I was dreaming before waking up and practiced the song over and over so it was stuck in my head, and then immediately after waking I wrote down the tablature. It ended up being a pretty good song, and (at least so far) I haven't heard anything else like it.

Obviously this is heavy anecdata, but I've never heard a scientific explanation of how to be certain whether or not you're dreaming (or as Descartes describes, being deceived by a demon).

>it's not a scientific test.

Isn't every subjective experience, almost by definition, unable to be tested scientifically?

We can objectively measure someone's brain activity during sleep, but we can't really measure their subjective experience. Implying that everything made up of subjective experience (like consciousness) can't be measured. Which also implies it can't be proven by scientific means. So in response to the GP comment, I'm not sure we can "know you're awake" (in the scientific sense, at least).

I'm pretty sure what you're describing is the hard problem of consciousness.

Yes, exactly, that's the point I'm getting at. We experience "life" through our senses, and our senses can be fooled. Even measuring brain activity requires a subjective level of "trust" that we're seeing a real machine that's taking real measurements, rather than a simulation of a machine. We can look for glitches in the matrix, but absence of evidence isn't evidence of absence.

It's wildly impractical to live your life like that, but at the end of the day we just don't know and probably can't know.

There are tried and true techniques, like checking your watch. When you're dreaming, it will show different times when you check it.

So if you train yourself to check your watch for consistency (in your normal everyday life), your unconscious will continue the practice in your dreams, and you'll notice the inconsistency.

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