first, allow me to say thanx to jake and chris for some amazing discussions on each episode.
as for episode 17 and 18 of the return, allow me to offer some pointers, that might help you with interpreting what the hell lynch and frost were up to with this series.
sorry for my lack of caps, but my keyboard is busted.i had to think for a while, after sheryl lee's final haunting scream transported us into a momentarily comatose state of despair.now i'm almost angry at myself for not figuring it out sooner - figuring out what lynch and frost were really going for with twin peaks the return. but i think it essentially boils down to this: much of lynch's work center around duality.while we have enjoyed many character moments of all sorts, nostalgia and tp mythology explored further in this season, there has been a constant underlying current of much greater ambition and horrific implications with us during the whole trip. we witnessed its birth in the now infamous episode 8 and it simply deals with a perverse interpretation of the episode 17 title 'the past dictates the future'.for cooper, it dealt with the possibility of changing the past in order to rectify the future. for a brief emotional moment, we the viewers, were led to believe that he pulled it off. laura palmer took his hand.but that narrative is crushed by the inevitability of what also happened in the past; humankind gave birth to the fury of evils own momentum and there is no stopping it. it doesn't matter what cooper does or doesn't do - from this moment on and until the end of our existence, we are forever trapped in the moment of laura's horrific echoing scream.
coopers arc echoes freds arc in lost highway. these created realities of their own making, will only present the exact same evils they are running away from. you can keep evil at bay, but never defeat it outright. cooper thinks he can by saving laura (which is a sign of human arrogance), but maybe laura was never meant to be saved. she was meant to die. and so it will be in every new iteration of reality that cooper and laura are doomed to repeat forever.
albert said back in season 2. bob is the evil that man does. how right he was.
these were my initial thoughts. hope they can guide some of you, if needed.
interesting note - the two episodes that went really deep with the inevitability of evil in our world, both has the number 8 in them - episodes 8 and 18. the infinity symbol that jeffries conjures from the owl symbol.