Keep in mind we are far deeper down the hole than we were in CS Lewis’s day. In 2020 subjectivism is firmly established as the reigning public philosophy, and you don’t have to look far to see how it has “remov[ed] ordinary checks to evil and depriv[ed] good intentions of their natural support.” In fact, we are teetering on the edge of an age of subjectivist authoritarianism that threatens to codify “affirmation” of individual delusions into law.
In order to dig our way out again, we will need, first, to recognize that subjectivism is the root of the problem, philosophically speaking, and second, to put in the intellectual work required to understand how subjectivism creates the problems it creates. Until we can articulate its flaws we will have no hope of exposing it for the disastrous moral fraud that it is.
The good news is that people don’t believe subjectivism because it is true or because it makes sense. They believe it because it is what they have been taught.
UPDATE 8/12/2021: It seems the video is no longer available on YouTube. Here is the text of the CS Lewis essay:
http://williamwoodall.weebly.com/uploads/1/0/2/2/10226906/the_poison_of_subjectivism.pdf
UPDATE 7/13/2022: It appears the video is back on YouTube.