Does Sans remember previous timelines or what? Like when you do neutral , pacifist , or genocide?

saveloadreset:

That’s a pretty common misconception. He seems to be vaguely aware of how SAVING and LOADING functions, and there’s some evidence, between his awareness of Papyrus having died in prior runs and the preservation of the True Pacifist photograph in his workshop, that there is some sort of continuity between the resets that he has access too. 

However, he doesn’t seem to actually personally remember anything. He asks us ‘not to tell the other sanses’ that we were never friends, referring, presumably, to the now-orphaned and soon-to-be-made timelines, with their own version of Sans. 

This line only makes sense if his memories are wiped and if he is as unaware as any other character, brought back to ‘zero.’ The main difference seems to be the fact that, he has some physical continuity, doesn’t he? The photograph hints that Sans can, at the very least, transmit some form of limited data across timelines. Enough to print a photograph, at least, and perhaps a little more. How much more? Well, I dunno, but I feel like he would behave a differently if he was aware of prior runs in any great detail. 

What he says, warning you not to touch Papyrus after you have killed him in a prior run, also hints that he may have some awareness of prior runs … Or that there’s something in Frisks’ expression as they look at Papyrus that sets him off. 

But, does he remember them? Nah. He says it himself in the Kill-All fight, doesn’t he? That the reason he finds it hard to try is that, one day, everything is going to be reset, and “We’ll just end up right back here, without any memory of it, right?” He includes himself in that statement, doesn’t he? He doesn’t remember.

I am more ready to accept that Sans uses tools, ‘readings,’ to figure out things about prior timelines than simply ‘remembering’ them. Persistent memory across timelines, however, seems to be limited to Asriel, Frisk and Chara, with that growing somewhat fuzzy around True Reset. Most of Sans’ knowledge seems to come from intuition, expertise … and perhaps other was related to how that mysterious photo persists across timelines.