“The world is not dangerous because of those who do harm but because of those who look at it without doing anything”
There are those who believe that not and only should always be placed as close as possible to the words which they modify. I am not of their number. It is only necessary to do so (see?) where there is a real risk of ambiguity. That is not the case with the Einstein quotation. The German original is slightly different, but there, too, the word for not immediately precedes the equivalent of dangerous.
There is a slight difference between reading it and hearing it. The first words "The world is not dangerous because of" can be initially parsed as: "the world is not dangerous" (premise) "because of" reasons why the world is not dangerous. We then have to recast the sentence as the premise being that the world is dangerous and the reason is not that...
As a comparison I invite you to consider how we parse the sentence "The old man the boats".
To be frank, it's a bit of a quibble, but it was a large part of my psych degree. http://jos.oxfordjournals.org/content/4/2/204.extract
I can honestly say that I didn't even notice you had changed the position of "not" until I closely inspected both sentences. So I'd say this is not an issue to worry about since it the sentence is perfectly comprehensible in both forms.
There is a shift in emphasis in your version toward a view that the world is going to be dangerous, regardless of what we do. Einstein's view seems to be that we can make the world less dangerous (by doing something about it).
Strictly speaking, the two forms are identical in meaning, and what I mean is that there is just a slight change in perspective, not a semantic difference.
For comparison, here is a purely hypothetical pair of statements, none of which have been made to my son:
- Dad: If you clean up your room, you can go to Josh's house.
- Mom: You can go to Josh's house, if you clean up your room.