# Re: Special Relativity

Daniel Fabulich (daniel.fabulich@yale.edu)
Mon, 22 Jun 1998 20:51:43 -0400 (EDT)

On Mon, 22 Jun 1998, Ian Goddard wrote:

> IAN: If the only other thing is B,
> A increased in size relative to B
> in the fashion described above. The
> simple fact that B appears to be
> smaller than A means that A appears
> to be larger than B to observer A.

You just don't get it, do you? OK, try this on for size:

B perceives A to be smaller than B. A perceives B to be smaller than A.
Who perceives other to be larger than self? If the answer is "no one"
(and it is!) thenthere is no positive sign on the identity chart. Period.

In one line, tell me in what reference frame A gets larger.

> Has A gotten larger than B? The only
> way for A to know is look at B. If B
> is smaller, then A has gotten larger.

As perceived by whom? In what reference frame has A gotten larger?

> The fact that both observers witness
> the same thing does not break this
> symmetry of relational structure.
> Both observers see themselves
> as larger than the other:
>
> A B (how I appeared)
> A 0 +
> B + 0

Did you make another error here? "Both observers see themselves as
larger than the other..." 0 is self, and 0 is SMALLER than +, not
larger.

> and both observed the other as smaller:
>
> B A (how the other appeared)
> B 0 -
> A - 0
>
> and the sum of all valid measurements equals 0.

The second chart is valid, but let's look at what the top row of your +
identity chart is saying: A percieves B to be larger than 0, and 0 is
self. Therefore, A perceives B to be larger than self.

*A DOES NOT PERCEIVE B TO BE LARGER THAN SELF.*

Therefore, the above identity chart is wrong.

> Nice try Dan, but time to find another counter,
> I've already toppled this one three times now.

How? By refusing to understand special relativity? Genius. I should
have thought of it earlier.

> If the size of A = 1 and the size of A
> = the size of B, but then B decreases
> in size to .5, it is a fact that 1 is
> LARGER than .5, and thus A has gotten
> larger relative to B because B got
> smaller relative to A. Simple.

So simple, it's wrong. Look, I want you to actually visualize this in a
real way. A's got a meter stick, which measures the same as B's meter
stick at rest. (They dynamically calculate this meter stick by finding
the speed of light, and taking one three-hundred millionth of it. This is
the definition of a meter.)

When they get moving, B's meter stick looks to be 0.8m long. So, you want
to say A's meter stick is growing? Relative to what? Not B: B perceives
A's meter stick to be SHRINKING, not growing. What is A growing relative
to?

> Because B was also size 1, it could
> be stated now that A = 1.5, for no
> point of size-reference is absolute.

Except that this is true in no reference frame, for if you measure A from
B's reference frame, you do NOT get 1.5: you get 0.5. If someone, ANYONE,
measured that meter stick to be 1.5m long, I'd agree. Except A never
measures any meter sticks to be longer than 1m, and neither does B. So,
from what reference frame is A 1.5m long?

> IAN: There is no absolute size, you cannot have
> "got smaller" free from "got larger." Observer
> A will measure the situation and see that there
> are two sides of the relative change: he himself
> got larger than B because B got smaller than A.

Relative to WHAT? A got larger relative to B? <BZZT> No, A got SMALLER
relative to B. Try again.

Until you can provide a reference frame in which B grows (that is, from
the perspective of observer X, B is 1.5m long) you haven't proved
anything. And unfortunately, from A's perspective all sticks are <= 1m.
Same for B. And with that, you're out of perspectives.