I was hanging out with a friend last night, and he brought this up to me and we ended up talking about this for quite a while. Hopefully I get most of this right from what I remember. Truth be told, I likely won't participate much in this thread itself. I'm quite bad at debating philosophy and I am not going to dilute myself and pretend that I am. Either way it was still really interesting food for thought and spurred up a whole bunch of other ideas. So much so that I wanted to share it here, see what people think, and let a discussion form.
It goes something like this. He opened it by talking about how a startreck teleporter would work. In essence, your body is dematerialized, and them put back together in another location. For a brief period of time, you stop existing. Then you come back together in another location. In effect, for a period of time, you are dead. It's no different then if a massive bomb went off, and you were blown to bits. The difference here, is you come back. So, is this actually dying? At this point we had a bunch of back and forth trying to figure it out. He argued that it is, and by definition, it is because your stream of consciousness stops (which is the premise that he set to define what death actually, regardless of the medical definition).
You could almost think of it like a direct clone of yourself in another location by the teleporter. Except one of you is "deleted" before the other one forms. It's both you (forgive me if I flub on the language and word useage, I'll do my best). An analogy could be drawn to the move the prestige. In it, the character gets duplicated in some Tesla created machine, and upon seeing his clone, one of him shoots the other him, so there is only one him. In that case, it's much easier to wrap your brain around the idea of "death" in that case cause it's explicit, and there is an overlap of existence. When duplicated, he is exactly the same, and there is no way at all for him to tell which of him is the original him. In essence, a teleporter is the same thing, just with no time overlap. Using this reasoning, you would "die" every time you use a teleporter, but there would be absolutely no way for you to ever perceive it because you seem to "live" on the other side. You simply just get copied with all memories intact.
He then went on further to extrapolate further that, if we define dying as loosing our stream of consciousness, then it stands to follow that every time we go to sleep, we "die". Our stream of consciousness stops. It turns off, and we have to be rebooted to get going again. It seems that it's no different.
I countered that going to sleep isn't dying however. If we definine it as stream of consciousness ending, then yes I am inclined to agree. However comparing sleeping to teleporting seems like an over-extension. Your body, or the "hardware" if you will, is the same. It's unchanged (well, mostly anyway), and you simply get turned back on. You come back. But he argued that from this perspective coming back is irrelevant, it's still a death event, and who you are is nothing more than a product of your physical body. So in effect the hardware of a body is meerly a tool. It's the software that's what matters. When your consciousness stops that version of you "dies" and won't come back. A new you needs to be put into place so you're reborn. However, because of the memories associated with the hardware of your body, you are unable to perceive that.
To that end, we're ok with sleeping cause, well, we have to be. It's required. Teleporter ideas make the idea seem more spooky and scary because it makes the concept of death seem more overt, as we see it as the decimation of a physical body. If the consciousness is what defines us as us though, then there should be no difference between the two.
Ultimately, his extension that you "die" every time you go to sleep doesn't seem right. It logically seems sound, but... I can not put my finger on it, but somethings off. I'll need to stew it over for a few days but maybe some of you will have other ideas. It's really really interesting to think about though. What I found pretty interesting is this whole concept was visibly scaring him and making him uncomfortable. I'll admit the idea of it is a bit spooky, but I am pretty much unphased and undisturbed by it.