Seth posted a smug-ish piece on “manipulation” the other day. He defined manipulation as: “working to spread an idea or generate an action that is not in a person’s long-term best interest”. This definition is not helpful.
The problem with Seth’s definition is that it’s impossible to determine what “a person’s long-term best interest” is. An Alinskyite leftist believes that by persuading people to organize in order to use power to force other people to give them stuff, he is helping those people. I believe that the vast majority of such beggar-thy-neighbor tactics erode the productive power of society, and ultimately leave everyone – particularly those near the organized – worse off than they would otherwise be. (As an example, I present Detroit.) Whatever your views on this particular question, I hope you agree that any definition that hinges upon such prudential judgements is meaningless.
Attempting to draw distinctions based on means, rather than ends, is equally futile. To persuade is to make an argument, to advocate. These are not even-handed or “fair” activities; they are biased, and, to someone who disagrees with your conclusions, misleading and/or deceptive.
Persuasion is a tool, to be used for good or bad ends. To attempt to define persuasion you disapprove of as somehow a different thing from persuasion you like (as Seth does with his “marketing”/”manipulation” dichotomy) is self-indulgent: It just lets you call something a nasty name. Not that that isn’t fun.