Miracle asked:

I. The Alpha Centauri star system has been visible from earth for some time into the past. It is a bit
more than four light years away from earth, which means that light takes about 4.1 years to travel
from Alpha Centauri to earth. This is all unproblematically understood in the conceptual framework of
naive realism.

II. A reference point is set: 1/1/2000; at which time the perception of Alpha Centauri from earth is
noted.

III. A thought-hypothesis: the explosion and immediate disintegration of Alpha Centauri on 1/1/2002.

IV. On 1/1/2004 an observer on Earth continues to see Alpha Centauri. The scientific reason for this
is that the photons from Alpha Centauri which are in the vicinity of the earth on 1/1/2004 had left
Alpha Centauri four years earlier; thus they had not been affected by the explosion.

There is a philosophical problem, if not scientific. What is it the observer on earth perceives on
1/1/2004? The problem is the star doesn't exist on 1/1/2004, Earth time. If one is currently existing at
time, relative to one's history, can one veridically perceive an object that does not exist at time, but
did exit relative to one's history?

P.S. The defender of scientific/ naive realism would say that on 1/1/2004 the observer truly or
veridically sees Alpha Centauri, but he/ she sees the star veridically at the moment of its existence
identical with 1/1/2000, Earth time.

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From the way you have framed your question, I take courage that you might gain some benefit from
reading a couple of chapters on relativity theory. Minkowski's geometricisation of the space/ time
theory actually gives you clear cut diagrammatic representations of this type of event and a simple
technique for solving it. So rather than give you a pre-digested 'answer', from which you would learn
nothing, go to the library and pick up a copy of Einstein and Infeld. It's all in there, from the horse's
mouth.

Jürgen Lawrenz

Sydney

I'm having difficulty seeing the problem here. What do you eversee? Photons. What do you ever
hear? Phonons, right? Which travel at the speed of sound, much slower than light, which people have
known for thousands of years. Do you have a problem that you see, for example, lightning, and then
hear the thunder a few seconds or minutes later, or see an explosion off in the distance and then hear
it later, etc. etc.? Does anyone?

A defender of naive realism would be naive indeed to say that they heard the lightning, or anything
else, "directly". So what's the difference? Light moves faster than sound, that's all.

Steven Ravett Brown