Does the sentence 『ボブは魚は好きだ』 make sense？


This question is essentially about the particle 「が」.

I saw the example sentence 「ボブは魚が好きだ」 from the textbook.

This is how I understand it:  
"As for Bob, Fish that is likable is. ---> Likebale fish as for Bob. ---> Bob
likes fish."

But then I wonder if the 「が」 gets replaced by 「は」 will it make any sense?

Thank you!




I will try to answer this question the way that I think beginning learners
could follow.

> 1) 「ボブは魚{さかな} **が** 好{す}きだ。」
>
> 2) 「ボブは魚 **は** 好きだ。」

Both sentences are 100% correct but there is a nuance difference between them
and therefore, they **cannot** be used interchangeably.

1)「ボブは魚 **が** 好きだ」 is the most basic way of saying "Bob likes (eating) fish."
It is straightforward in meaning and it does not have any implicit nuance of
any sort. That he likes fish is all the information the sentence conveys.

2)「ボブは魚 **は** 好きだ。」 is different in that it is nuanced and it chooses the
context to appear in. The sentence implies that there are things that Bob
**does not** like eating. That is why this 「は」 **in bold** is called the
"contrastive は".

In real life, the sentence 「ボブは魚 **は** 好きだ。」 would rarely, if ever, appear all
by itslef. Since it uses the contrastive は, it will mostly appear in contexts
where contrast is being made. For instance, we say:

> 「ボブは魚 **は** 好きだが、肉{にく} **は** 好きじゃない。」

The nature of the contrastive は often makes itself appear multiple times in a
sentence as above -- "likes fish but doesn't like meat". It takes two to
tango-ntrast, as we say in Nagoya.

You could of course split the sentence above into two separate sentences and
say:

> 「ボブは魚 **は** 好きです。でも、肉 **は** 好きではありません。」

(There is also a way to turn the topic-marker 「は」 in 「ボブは」 into the
contrastive 「は」, but that would be too much for one thread.)

