Yes I would call that ludricrus. It is clear that it is claimed ALL velocity is relative to somethingelse. You cannot simply say I have a velocity of 1,000 Mph such velocity has to be relative to some other object or spatial ordinate.
So, you agree that all velocity is relative to something?
But, you don't agree that the plane's velocity relative to the plane is zero?
It is clear that v=0 is a velocity value and therefor v=0 must be relative to something other than ones self. Compared to ones self one NEVER has motion and would forever be at rest.
You contradict yourself, Mac. But, the second sentence is sufficient:
"Compared to oneself, one never has motion and would forever be at rest."
That sentence is
precisely what relativity says, and precisely what you seem to claim is ludicrous.
Or perhaps you are confused by accelerating things? Well, you can consider velocity relative to something at a different time.
For example:
A car accelerates from zero to 100mph. The velocity of the car is 100mph relative to it's motion before accelerating.
No it is not the same. That is the error in SR and cause of reciprocity which does not work and is why you consider who switched frames so as to determine who has actual velocity.
Yes but that does not mean they both have motion. Motion and relative velocity are two distinctly different things.
SR doesn't say anything different to Galileo in this case.
Are you saying that Galileo was wrong?
Yes and no. If at inertial rest and I accelerate and become inertial again it may or may not be at rest. Also at rest relative to what?
Exactly! That's exactly what Galileo and SR say - that you can't tell from any history of acceleration whether a thing is at rest, and that 'rest' is a relative term.