The cells on the tips of my fingers are *promote-ing this.

Promoting this video and sending it back into the queue for one more try; last queued Tuesday, May 31st, 2016 10:54am PDT - promote requested by iaui.

CGP Grey - You Are Two (Brains) has been added as a related post - related requested by eric3579 on that post.

my brain cells think this is goddamn *quality

Boosting this quality contribution up in the Hot Listing - declared quality by ChaosEngine.

Cells have no "purpose"?

I think that depends on how you define "purpose". I don't think humans (or other animals / organisms) have any particular intrinsic purpose. At least, nothing granted to us by a higher power or outside influence or whatever. We assign purpose to ourselves, and to other fuzzy-boundary collections of things. Things that are "alive" exist to use energy, move, reproduce, etc. Things that are "tools" exist to be a preferable means of accomplishing some task. Etc.

If any of those things have "purpose", certainly cells can have a "purpose" as well. Neurons exist to transfer bio-electric currents. Rod and cone cells in our eyes exist to react to light in general or particular wavelengths of light.

I don't think that we have any physical or intangible soul that serves as the core of our being. We have cells, organs, and organ systems that make up a "meat computer" that provides us with consciousness (a word that we invented, but which describes a fairly concrete idea), and I would argue that consciousness is the closest thing that we have to a "soul".

At some point, if we can create a machine that emulates / replaces the functionality of all those cells, organs, and organ systems that are responsible for consciousness, and copy a snapshot of the states of all of that in an organic being (like us) into a mechanical counterpart, then ... yeah. I think that machine would be the organic being that it was a copy of, in a far more meaningful way than Henrietta's cancer cells are "her".

To me, the problem reduces to this:
1) Brain is the hardware
2) Current charge of neurons is the software that we like to call consciousness.

Consciousness, just like software, is intangible. This video about cells didn't bother to distinguish the "who" from the "what" when it talks about "us".

There are established fields in ontology and epistemology that address this very problem better than the "cells" argument. For anyone interested, I'd start here first.