When you expose yourself to ideas, you’re letting your brain soak in a stew of reinforcement structures. You’re inevitably open, as a human, to pressure that has nothing to do with the actual quality of the ideas you’re engaging with. For example, if some people with bad ideas also have strong social norms enforcing those ideas, it’s very difficult for creatures like us, who are social at their core, to disentangle the ideas from the social gains we might make by believing them.
I’ve found that if you pay close attention, you can feel this happening. Maybe it’s partially a self-delusion, but if you take stock of your mentality, and then deeply engage with some set of ideas for a while, and then take stock again, I bet you’ll find your views have shifted. This almost invariably happens to move your thoughts toward favoring the ideas you’ve been reading about, even when you strongly disagreed with them before. Some of this may be introducing nuance to ideas that you had previously boxed as completely untenable, but I think some of this is also a sheer fact that we are vulnerable to believing things just because we see them around us.
When I can feel my views shifting towards some set of ideas I previously disagreed with, merely because I’m spending more time with those ideas, it makes me feel less cognitively invulnerable than I felt before. Having an open mind is usually viewed as a virtue, and I think we’re generally right to do so. It’s overwhelmingly likely that someone else who’s thought about something more will have at least some piece of nuance to contribute that positively affects your view of the subject.
All of this makes me think that carefully choosing what I read is even more important than I thought it was before, and that I should perhaps be slightly biased against anything new I’m reading, no matter what side it’s arguing for, because simply by reading it I’m subtly changing my mind to favor the ideas it espouses.