Thanks.
"From the assumptions of special relativity, it can be shown that for two events separated by x and t in a "rest frame" and x' and t' in a frame moving at speed v relative to the rest frame, c 2 t 2 − x 2 = c 2 t ′ 2 − x ′ 2"
So I guess I need the bit about "It can be shown that". I...
Great book. Reading it for the second time. There are several "jumps" that are made in their lines of reasoning that certainly make the explanations easier to follow, but also left me wondering "Why or where did that assumption or statement come from?"
On page 77 (in my 2009 Da Capo Press...