Paradox is human-only
Cats, Dogs, Trees, and etc do not experience paradox
It is more accurate to say that Monsters do not experience paradox because they have stopped being human.
This isn't true--certain monsters
do experience Paradox, in the form of Disbelief. This is why unicorns, dragons, and the like can only survive in special reality zones or in the Umbra. They were driven from their former homes by weaponized disbelief. Interestingly, in addition to Fera, vampires, spirits, hunters, mummies, et cetera, M20 says that aliens are not subject to Disbelief either.
Anyway, my hypothesis is that the Consensus is an artificial construct, created as part of an evil plot. For most of history it did not exist, and it has gradually been strengthening and affecting more things over time. My reasoning:
1. Creating Consensus distracts mages from actually doing the hard work of improving the world materially, in favor of just trying to convert people to their ideology. For instance, if Consensus is potent, you don't need to reduce carbon emissions to stop global warming. You just need to convince people that global warming doesn't exist.
2. There are alternative routes to magic, such as sorcery. Mages like to explain these as "mythic threads," but this makes no sense. If they are established enough in the Consensus that an ordinary person can do them, mages should be able to do them as well, just like how a mage can use a cell phone. Instead, they can't. If a mage tries, despite doing the exact same thing as a sorcerer, their magic incurs Paradox. There are no rules for sorcery interacting with reality zones, despite the fact that if they're mythic threads they should. Furthermore, there are rules in M20 Sorcerer for creating new sorcerous paths, and "convince people that it's possible" isn't part of it. Several paths do not bear any resemblance to anything from folklore either; what folklore is there about transferring storms from the underworld to the world of the living to calm ghosts?
3. The Time of Judgment scenario focusing on Nephandi tried to emphasize that there are no simple answers and anything that appears to be a simple answer is actually a trap. While changing people's minds is hard, "if we all agree, we can will utopia into existence" is still
much easier than the work of actually constructing a better society from the ground up.
4. Aliens aren't affected by Consensus (the book suggests that their vulnerabilities
may be the effects of Consensus, but it's a possibility at most). While some may argue that this is because people sort of believe in them, by that logic they should suffer ill effects in reality zones where people don't believe in them, and aliens with clearly supernatural abilities should probably receive some sort of penalty. Creatures such as Bigfoot are affected by Consensus
despite a large number of people believing in them too. It makes more sense if, being outsiders, Consensus just hasn't had time to affect aliens.
5. Consensus is
suspiciously good at genocide. Countless intelligent species have been driven extinct or nearly extinct or driven from their homes because of it, and it allows one civilization to make another civilization's basis for existence cease to exist. Consensus often gets seen as a potentially liberating thing in Mage... but should such a terrible weapon exist?