Sunday, November 19, 2023

A variant on an argument of Unger

  1. In some ordinary reference frames, there are times at which I am less than a nanometer in size. 
  2. If I am fully material, I cannot ever be less than a nanometer in size in an ordinary reference frame.
  3. So, I am not fully material.
The same argument applies to dogs, fish and trees, and not just people. And I embrace that conclusion, since I think they all have form, and form is not material. But it is less of a bullet to bite to deny the existence of dogs, fish and trees than to deny one's own existence.


StardustyPsyche said...

If I am fully material, I cannot ever be less than a nanometer in size"
Why? In your local reference frame everything seems normal because everything scales.

It's like the twin "paradox", you know, where on person travels in space near the speed of light for an extended trip, then returns back to Earth to find the other twin very old.

To each twin time seemed to pass ordinarily because everything scales locally.

"in an ordinary reference frame."
All frames are ordinary. There is no preferred reference frame.

Heavenly Philosophy said...

Happy Thanksgiving! (even though you're Canadian)

Alexander R Pruss said...


"Ordinary" is relative to us, here on earth, in a reference frame only a little bit different from the reference frame of the earth's center of mass.

That's the surprising result: Just *before* death, in almost every reference frame, including in almost every ordinary reference frame, you are less than a nanometer in size.

StardustyPsyche said...

"That's the surprising result"
Hmm... I feel like I missed something here. Result from what?

"Just *before* death, in almost every reference frame, including in almost every ordinary reference frame, you are less than a nanometer in size."
Well, I must say, I did not anticipate that statement!

Right now my body is a very great deal larger than a nanometer.
After I die that body will remain nearly the same size as it is right now, hardly a mere nanometer.

So, to get from 1.8m to 1.8m the object must pass through a phase of being 0.000000001m?

Alexander R Pruss said...

It would have helped if I drew a diagram. Imagine that space is two-dimensional and time is one-dimensional and that in your rest frame your 2+1 dimensional shape over your lifetime is a perfect time-directed cylinder, i.e., you are a disc in space and that disc exists for a certain period of time, at rest. Then any slice of you at right angles to the time axis will be a disc. If you slant the slice at a tiny angle, then the slice will usually be elliptical. But if you take a slice very near the top and bottom with a slight slant then that slice will be a tiny sliver--and by making the slice be closer to the top or bottom, you can make the sliver arbitrarily small. That sliver is you at the time corresponding to that slice in that reference frame. It might be a very insignificant slice--it might be a slice of your little toe, say. A slightly slanted slice corresponds to a reference frame moving relative to you at a slight velocity.

The same conclusion applies regardless of what shape you have--there will always be a slice of you near the death side (as well as another one near the conception side) that is very small.

Here are some ways out of the argument:
1. Allow that there are many (maybe even infinitely many) people roughly where you are, each differing slightly in 4D extension.
2. Hold that whether you exist at a specific spacetime location depends on the reference frame.
3. Deny that if a spacetime location z is inside your four-dimensional extension, then you exist at every time t that contains z. In other words, hold that a part of you can exist at a time at which you don't exist. (And not just in the sense that your skull can exist after you are dead. For when you are dead, your skull is not a part of you any more.)

StardustyPsyche said...

"Imagine that space is two-dimensional and time is one-dimensional"
But there are 3 spatial dimensions. No need to imagine only 2.

"If you slant the slice at a tiny angle"
I don't live my life by slanting a slice.

The material that makes up my body does not progress through a nanometer size phase just because I die.

Death is like turning off the motor in your car, or unplugging your computer, or turning off your vacuum cleaner. Moving parts just stop moving the way they were moving previously, that's all. They don't care about your abstracted slices or you imagining nanometers or anything else you are imagining.

The material that makes up my body moves in identifiable ways when I am alive and stops moving in some of those ways when I die, that's all.

StardustyPsyche said...

But while I gotchya on the line, I left a comment about the barn door tracker but it did not post! Darn, my comment seems to have gone to bit heaven :-)

Well, it was one of my flight of ideas stream of consciousness blurbs on how to use a 3D printer to make a drive for the barn door tracker that eliminates cumulative tracking error.