At one point I believed in nurture completely, but now I'm not so sure. Some people are inherently selfish and aggressive, it seems. And while one could argue this is all due to conditioning, I don't think you can completely remove an individual's brain.
We don't believe everyone has the same capacity for intelligence of course. That is just not true. Why should we believe everyone has the same capacity for compassion?
Ya, I used to think it was all nurture too until I had kids and witnessed other kids with knowing their parents and I don't believe it's pure nurture anymore. It's a bit of both. People's personalities aren't learned. There's something in their nature that shapes that. How they respond to things certainly is taught to a certain extent, but their personality also impacts their tolerance or willingness to respond to certain behaviors. Seeing kids in the same family be completely different despite the same upbringing environments has shown there has to be some element of nature to it. Plus we talk all the time about kids being on the spectrum now which isn't a binary thing. So knowing that there is that variance which can impact how their behavior is, why are we so quick to completely blame it on nurture these days? I no longer assume it's the parent's fault if a kid does something bad. It could be, but it's not always the case.