Quote Originally Posted by Delta View Post
Yeah, that definition has always been problematic and was quite divisive even back in the day. The whole basic principle feels wrong to me, Essence is directly tied to Magic, so giving it a purely "scientific" explanation doesn't really cut it for me.

I still like the "aura blueprint" interpretation for Essence. Your aura is what makes you alive, it's a magical "blueprint" of your body and channels mystical "living energy" from the astral plane through your body, so to speak. The more you modify your body, the more different it becomes from your aura, so less of that energy makes it into your body, your aura gets weaker. Easy to understand, easy to work with, it also explains cyberzombies quite well which didn't really make a lot sense with the M&M description.
And yet a cultured bioware arm replacement - grown from your own cells, so, basically, it's your arm in all ways - costs essence. Yes, it's only 0,02, but even that knocks mages or adepts down a peg if they lose an arm. Personally, I got rid of that, because it just doesn't make any sense either mechanically or by fluff.