I think what you gain by reading is exposure to someone else's way of thinking. You won't get that by sitting in a vacuum. If you're impressionable, you just assimilate the author's way of thinking without any criticism. That shouldn't be the goal here.
The key part of that quote (whether it's real or not) is the "and uses his own brain too little" part. It's not as helpful to read a book mindlessly like you're watching television and I think you're missing out on so much by just reading technical manuals. You need to form your own opinion about what you're reading by drawing on your own experience and things you've learned.
I'm pretty sure you didn't develop your way of thinking by yourself. You were influenced by mentors and other people's thoughts and opinions. So why would you intentionally stop evolving? How do you know you've reached some "optimal mental state"?
As an aside, if you're into well-written technical books that are enjoyable to read, check out Operating Systems: Three Easy Pieces:
http://pages.cs.wisc.edu/~remzi/OSTEP/
The key part of that quote (whether it's real or not) is the "and uses his own brain too little" part. It's not as helpful to read a book mindlessly like you're watching television and I think you're missing out on so much by just reading technical manuals. You need to form your own opinion about what you're reading by drawing on your own experience and things you've learned.
I'm pretty sure you didn't develop your way of thinking by yourself. You were influenced by mentors and other people's thoughts and opinions. So why would you intentionally stop evolving? How do you know you've reached some "optimal mental state"?
As an aside, if you're into well-written technical books that are enjoyable to read, check out Operating Systems: Three Easy Pieces: http://pages.cs.wisc.edu/~remzi/OSTEP/