Re: Where Is Now? The Paradox Of The Present
- awesome post.
>The night sky is a time machine. Look out and youlook back in time.<
I don't believe that. I just see points of light. Now what?
--- In email@example.com, medit8ionsociety <no_reply@...> wrote:
> by Adam Frank
> From the NPR website:
> The night sky is a time machine. Look out and you
> look back in time. But this "time travel by eyesight"
> is not just the province of astronomy. It's as close
> as the machine on which you are reading these words.
> Your present exists at the mercy of many overlapping
> pasts. So where, then, is "now"?
> As almost everyone knows, when you stare into the
> depths of space you are also looking back in time.
> Catch a glimpse of a relatively nearby star and you
> see it as it existed when, perhaps, Lincoln was
> president (if it's 150 light-years away). Stars
> near the edge of our own galaxy are only seen as
> they appeared when the last ice age was in full
> bloom (30,000 light-years away). And those giant
> pinwheel assemblies of stars called galaxies are
> glimpsed, as they existed millions, hundreds of
> millions or even billions of years in the past.
> We never see the sky as it is, but only as it was.
> Stranger still, the sky we see at any moment defines
> not a single past but multiple overlapping pasts of
> different depths. The star's image from 100 years ago
> and the galaxy image from 100 million years ago reach
> us at the same time. All of those "thens" define the
> same "now" for us.
> The multiple, foliated pasts comprising our present
> would be weird enough if it was just a matter of
> astronomy. But the simple truth is that every aspect
> of our personal "now" is a layered impression of a
> world already lost to the past.
> To understand how this works, consider the simple
> fact, discussed in last week's post, that all we
> know about the world comes to us via signals: light
> waves, sound waves and electrical impulses running
> along our nerves. These signals move at a finite
> speed. It always takes some finite amount of time
> for the signal to travel from the world to your
> body's sensors (and on to your brain).
> A distant galaxy, a distant mountain peak, the not
> very distant light fixture on the ceiling and even
> the intimacy of a loved one's face all live in the
> past. Those overlapping pasts are times that you ï¿½
> in your "now" ï¿½ are no longer a part of.
> Signal travel time constitutes a delay and all
> those overlapping delays constitute an essential
> separation. The inner world of your experience is,
> in a temporal sense, cut off from the outer
> world you inhabit.
> Let's take a few examples. Light travels faster
> than any other entity in the physical universe,
> propagating with the tremendous velocity of
> c = 300,000,000 m/s. From high school physics
> you know that the time it takes a light signal
> moving at c to cross some distance D is simply t = D/c.
> When you look at the mountain peak 30 kilometers
> away you see it not as it exists now but as it
> existed a 1/10,000 of a second ago. The light
> fixture three meters above your head is seen not
> as it exists now but as it was a hundred millionth
> of a second ago. Gazing into your partner's eyes,
> you see her (or him) not for who they are but for
> who they were 10-10 of a second in the past. Yes,
> these numbers are small. Their implication,
> however, is vast.
> We live, each of us, trapped in our own now.
> The simple conclusions described above derive,
> in their way, from relativity theory and they seem
> to spell the death knell for a philosophical stance
> called Presentism. According to Presentism only
> the present moment has ontological validity. In other
> words: only the present truly exists; only the
> present is real.
> Presentism holds an intuitive sway for many people.
> It just feels right. For myself, when I try and
> explore the texture of my own experience, I can't
> help but feel a sense of the present's dominance.
> Buddhism, with its emphasis on contemplative
> introspection, has developed a sophisticated
> presentist stance concerning the nature of reality.
> "Anyone who has ever mediated for anytime" the
> abbot of a Zen monastery once told me "finds that
> the past and future are illusions."
> Yes, but ...
> The reality that even light travels at a finite
> speed forces us to confront the strange fact that,
> at best, the present exists at the fractured center
> of many overlapping pasts.
> So where, then, are we in time? Where is our "now"
> and how does it live in the midst of a universe
> comprised of so many "thens"?
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