He qualified it with "(of types)", so I believe he was talking about inheriting from multiple interfaces. People already had to be able to deal with "this thin

He qualified it with "(of types)", so I believe he was talking about inheriting from multiple interfaces. People already had to be able to deal with "this thing is both a Foo and a Bar", so perhaps it's not a huge leap to go from there to "this thing inherits implementation from Foo and Bar". And by implementation we mean methods, not state. That's how I read it at least.