Deconstructing humans

I often make the point that if a man is just an ephemeral, fortuitous collection of particles, then human life has no significance. Now someone might accuse me of committing the composition fallacy. To which I'd say the following:

i) Not all part/whole inferences are fallacious. If every part of a marble bust is made of marble, then the entire bust is made of marble. 

ii) Let's sharpen the objection. A critic might say that if stones are arranged to spell out S.O.S., then that's meaningful. You can't say it's reducible to the individual stones. 

Likewise, they say what makes humans significant is the entire physical organism. How the parts are interrelated.

iii) There are, however, problems with that comparison. To begin with, you have the familiar "hard problem of consciousness."

iv) Over and above that, the illustration is counterproductive. If, say, the stones accidentally formed that pattern, due to erosion, it wouldn't really be a message. To be a message, the stones must be arranged with the intention of expressing a message. Someone had to do it with that in mind. 

In addition, the abbreviation has no inherent meaning. Rather, it's code language. The meaning of language is not inherent in the arrangement of letters or vocables. Rather, meaning is assigned to words by speakers and listeners. 

If humans are reducible to bodies, human significance must be extrinsic rather than intrinsic to humans. And arrangement of matter is not inherently significant. 

v) In addition, my contention isn't confined to physicalism. There are other factors. If there's no afterlife. If, once we die, it's as if we never existed.

If human existence is the byproduct of a mindless, amoral natural process. No inherent purpose or value.