Or look at this question. Flight IC 945 takes off on Monday, with a set of crew members operating a certain aircraft and with a bunch of passengers. On Tuesday, Flight IC 945 takes off with a different crew operating a different aircraft and with a completely different bunch of passengers. How can both flights be IC 945, just because they are operating on the same route? Nothing else is the same.
None of you know anything about me, except that my name is Raj. I am just a virtual entity as far as you are concerned. Suppose tomorrow, someone starts a blog on another URL, calls it Plus Ultra and signs his name as Raj, will you know the difference? Worse, suppose someone steals my password, uses my URL and posts blogs in the name of Raj, will it matter at all to you?
Or I use the same URL and same blog name Plus Ultra, but start posting in the name of Zabernosky, would you care? Will the virtual entities Raj and Zabernosky mean the same to you, as the content and style will be the same? Will the images of both these characters be the same in your mind? Or Raj will be clean-shaven and Zabernosky will have a long beard?
Profound questions. Profound questions. Must think.