We discover the Athena's daughter has been in a coma for several years. Her father wants to end it already, but Athena can't bear to do this. That, combined with her AI speaking about a waterfall that appears in a photo of Athena and her daughter that Athena cherishes, put this all into high relief: Athena is investigating and trying to create a form of conscious synthetics - or, as one synth aptly put it, synths that are "awake" - because Athena is hoping to embed in a conscious synch the personality, psyche, or call it soul, of her daughter.
This makes Humans an even more profound narrative about intelligent androids than it was. It's one thing to create conscious synchs out of nothing, or no previous mentality or existing being. I mean, that's incredible indeed, certainly. But employig that digital sophistication to give humans immortality is something quite else, and more.
In a way, this is what motivated Dr. Millican in Season 1. But Athena's seems to be more explicit, and echoes strongly with a novel that hasn't received enough attention over the years - The Silicon Man, a 1991 work by Charles Platt, which explored the form of immortality achieved by uploading someone's mind into a mainframe computer (see my review). It's a theme that has also been explored in many a movie, but The Silicon Man does it best, including the issue of whether it would be murder or suicide or ... to end the fleshy existence of someone whose mentality was uploaded and and from that new ensconcement ordered such termination.
Androids, while not necessarily made of flesh, do have a mobility that Platt's mind in a mainframe didn't have. In effect, putting someone's mind into a synth - Athena's daughter or whoever - may be more akin to cloning than what Platt was playing with. But it will be fun to see where Humans goes with this in any case.