The problem with making ‘yes means yes’ the standard for sexual assault - The Washington Post

"The idea behind affirmative consent sounds harmless enough; make sure your partner is actively interested rather than passively going along. But legal systems cannot be run on harmless generalities. They demand firm guidelines, and so many advocates for affirmative consent say you must obtain unambiguous agreement before you so much as touch the other person, and at each step thereafter.

Frankly, one suspects the classic public choice problem: regulators who have no direct experience with the activity they propose to regulate. As everyone else knows, but affirmative-consent supporters are apparently yet to discover, the sexual ideal is to lose yourself in the moment, the other person. That cannot happen if every encounter must be navigated with the lawyerly detachment, and mutual wariness, of a bilateral trade negotiation.

Worse still, if one party later claims they weren’t willing, affirmative consent effectively shifts the burden of proof to the accused, while leaving no way to provide that proof, absent a written contract. Or even any way to know that what they’re doing is legal — your partner may have been saying, “Yes, please!” five seconds ago, but what if that’s followed by a lull in the person’s active participation? “What about now?” ...

But as any biologist, or sales-force manager, can tell you, systems that rely entirely on positive feedback are unstable. They have no natural stopping point, no way of saying “enough.” Which is the fundamental problem with affirmative consent: There is no way to be completely sure that consent was sufficiently affirmative. That’s why good systems almost always incorporate at least some negative feedback — and why rape laws have historically relied on “no means no,” not “yes means yes.” ..."