is it true that it's impossible to cognize (not sure what work "cogniz[e]" is doing) the experience of (again, not sure what work "experience of" is doing here) death rationally? Or is it just the case that the thought of our personal extinction is, well, unpleasant? It seems to me that it's easy to conceptualize death. Go to the wall and flick the light switch. One second the light is on, the next, it's off. The off position is death.
First off, as a heathen myself, I find the matter-of-fact nature of Emery's metaphor quite appealing; I'm somewhat drawn to the idea that death is fairly simply. However, I think Emery is cheating here. He dismisses the work done by 'cognize' and 'experience' so that he can then go on to 'conceptualize' death by offering us this very nice metaphor. But conceptualizing death is not cognizing its experience. The work cognize is doing is to make the link to epistemology. This means we're not just saying what death is like (as Emery's quote does), but saying something about knowing death.
How can we know our own death, or know an experience of it? This is the question that TMcD says leads us to religion. I see how the question drives us to religion, but I don't see how it really answers the question. That is, here I side with Emery, because I think religion is more like a metaphor or a conceptualization; it tells us what death is like, or how it's going to be, but it doesn't allow us to cognize it. And, in that sense, Emery's light switch response is spot-on.
On the other hand, I'm probably missing something about the religious experience; of course I am, since I don't have the religious experience. But the question about cognizing death doesn't have to lead to religion. It could lead to Heidegger. It could lead to an awareness of our own finitude in the world. It could lead to a realization of the limits if epistemology, which means that in asking about 'cognizing death' we're asking the wrong question.