Simply have no life of my own, so i wrote a list of all the contradictions and plotholes the Catalyst’s brings by its motivations and existence:
1) If the Catalyst is itself an AI, why does it care about organics?
2) If the Catalyst is itself an AI, then doesn’t it by its own logic want to destroy all organics?
3) If the Catalyst was on the Citadel and is a being of complete power, why could it not activate the Citadel Relay itself, making the Vanguard and the keepers obsolete.
4) If the Catalyst was on the Citadel and is a being of complete power, why could it not shut off the relays itself and grant the Reapers access, given them an easy victory.
4) If the Catalyst was on the Citadel and is a being of complete power, why could it not kill the leadership of this cycle to ensure the Reapers would not be defeated.
5) If the Catalyst was on the Citadel and is a being of complete power, why could it not indoctrinate the leadership of this cycle to ensure the Reapers would not be defeated.
6) If the Catalyst was on the Citadel and is a being of complete power, why did it not try to kill Shepard once he became a threat to the cycle all the times he was on the Citadel? The Reapers defiantly did not pass up any chance offered, so they were not interested in preserving him for study.
7) If the Catalyst wants to preserve the culture and insight of a species in the Reapers, why did the Reapers, after finding the Protheans could not be turned onto a Reaper, reduce them to mindless drones, destroying all their culture and insight?
8) Why is the Catalyst incapable of using any of the choices itself? If it is an AI with the personal creativity to produce an inventive solution to a problem on its own, how can it not choose a new solution by itself?
9) How does the Catalyst know that synthetics will destroy all organics with such certainty? Has he seen this? No because there is still organic life and if organic life can survive that then his motivation is pointless. Has he seen this in another galaxy? Then why is he in this one? Why only the Milky Way galaxy? How did he travel between galaxies when the Reapers can't even do that?
10) If the Citadel can move, as shown with the Reapers moving it to Earth, why couldn’t the Catalyst tell Sovereign where to go and meet him there, so fast the Citadel Fleets couldn’t catch up?
11) How did the Citadel move? Can it pass through mass relays when it is much bigger then them? Can it move with its own relay, because relay have never been shown to be able to pass through their own network.
12) If the Reapers had enough control over the Citadel to move it without having the keepers under their control, then why couldn’t they have shut down the relays and let the victory fleet starve while they finished on Earth?
13) If the Reapers were so worried about Shepard reaching the relay beam on Earth they sent Harbinger to stop him, why didn't the Catalyst just turn the beam off?
14) If the Catalyst knew the Illusive Man's intentions to control synthetics using the Crucible before the Crucible docked, why didn’t it try to destroy the Crucible to prevent it stopping the cycle and enslaving his Reapers? Why not order all Reapers to focus on it?
15) If the Catalyst was on the Citadel, would it not have heard about the Crucible and attempt to destroy it before it became a threat?
16) Why didn't the Catalyst, in the Mass Effect, keep the Citadel arms closed after Saren died (for the first time) to protect Sovereign from the fleets? Why would it risk endangering a Reaper when its motivation is to preserve organic races in them?
17) How can the Catalyst not notice the geth fighting alongside organics and the AI fighting alongside Shepard as testament that its logic is wrong?
18) If the Catalyst wants to stop synthetics from destroying organics, why not use the Reapers to destroy synthetics?
19) If the Catalyst wants to stop synthetics from destroying organics, why on two separate occasions have his followers recruited and even upgraded synthetics to fight organics for them?
20) If the Catalyst wants to stop organics creating synthetics, why not tell the races on the Citadel not to make synthetics or they will be destroyed? Why keep the existence of the Reapers a secret at all when it only encourages organic experimentations in synthetic creations.
Please add more if you want. I think ill think of more later.
21) How exactly does the Catayst's logic work? It fears uncontroled synthetics will wipe out all organics rather then the Reapers who just wipe out advanced species, but think about this. To "wipe out all organic life" you would have to go to every life bearing world and destroy every bacteria alive as well as destroy all pre-garden worlds before they produce life. And you would have to keep this up for bllions of years since garden worlds are constantly be created over those long time periods. Is this not the same thing as the Reapers, just drawning the line of "acceptable targets" a lot lower? Are we not, in our own way, the same as bacteria, in that we are merely a state of mutationa and evolution that is constantly changing and will surpass us to the point were we seem like mere bacteria? T Because if any of those bacteria survive they may evolve and advance. Does the Catayst really have such a dark view of its own kind? Would synthetics really have the resources and the inclination to do that?