mewes6190 wrote:Yeah, okay, that's kind of what I meant - that BOTH fruits are the topic of the discussion! And yes, it's a comparison, but if I get 奈津子先生 right, she added that such a comparison by は makes both (or even possibly more?) matters which are compared to the shared topic.
Personally, I see them as two separate topics. However, this may just be a difference of opinion as to what "topic" means. I'm using it to mean the grammatical topic, the one that gets marked by は and which is the focus of what follows. So in the sentence 「りんごは好きですが、みかんは嫌いです」 the topic starts off as りんご and what follows applies to りんご up until the topic is changed to みかん. At this point みかん becomes the new topic and what follows is about みかん and not about りんご.
Like 奈津子先生 says, the sentence makes sense because there's an overall theme or idea that applies to both topics. This theme or idea isn't a topic, though--at least, not in the sense that I'm using the word "topic". This example is an attempt to write a "contrastive" sentence with two topics but without an overall theme or idea (and which therefore makes no sense):-