Body identity assumes that a person is defined by the stuff of which a human body is made. Only by maintaining continuity of body stuff can we preserve an individual person. Pattern identity, on the other hand, defines the essence of a person, say myself, as the pattern and the process going on in my head and body, not the machinery supporting that process. If the process is preserved, I am preserved. The rest is mere jelly.
Consider the message "I am not jelly". As I type it , it goes from my brain, into the keyboard of my computer, through myriads of electronic circuits and over great amounts of wire, and after countless adventures shows up in bunches of books like the one you're holding. How many messages were there? I claim it is most useful to think there is only one, despite its massive replication. If I repeat it here: "I am not jelly", there is still only one message. Only if I change it in a significant manner: "I am not peanut butter" do we have a second message. And the message is not destroyed until the last written version is lost, and until it fades sufficiently in everybody's memory to be unreconstructable. The message is the information conveyed, not the particular encoding. The "pattern and process" that I claim is the real me has the same properties as the message above.
That self, mind, personality, etc, are all conventional phenomena, needs no saying, and really doesn't change anything on the subject -- since it has "always" been a conventional phenomenon. Similarly, lasers and neutron stars are also conventional phenomena.Suppose I step into the transmission chamber. The transmitter scans and disassembles my jelly-like body, but my pattern (me!) moves continuously from the dissolving jelly, through the transmitting beam, and ends up in other jelly at the destination. At no instant was it (I) ever destroyed (...) As a computer program, your mind can travel over information channels. A laser can send it from one computer to another across great distances and other barriers. If you found life on a neutron star, and wished to make a field trip, you might devise a way to build a neutron computer and robot body on the surface, then transmit your mind to it.
I'd be interested to hear your words on the subject and how it relates to Buddhist understanding.