Choosing between そうだ, ようだ and はずだ


From an
[article](http://www3.nhk.or.jp/news/easy/k10011086301000/k10011086301000.html)
written on the 7th of the month:

> 東京から日本のほかの場所に向かう「下り」の飛行機は、１１日が特に混み **そう**
> です。東京に向かう「上り」の飛行機は、１５日〜１６日と１９日〜２０日が混み **そう** です。  
>  For planes heading from Tokyo to other places in Japan, the 11th will seem
> particularly crowded. For planes heading towards Tokyo, the 15th to 16th and
> 19th to 20th will seem crowded.

I'm confused by the nuance that そう is adding to these sentences. I'm assuming
these are guesses based on previous years' flight statistics, so I would have
expected something like はず or よう to be used instead.

Could you please provide some explanation as to why そう is the best choice, and
whether はず or よう would also be appropriate here?

My understanding is that 混みそうです means that when I look around I will have a
feeling that it is crowded ("It will seem crowded"). Whereas 混むようです means that
based on evidence I predict it will be crowded ("It seems that it will be
crowded"). Could you please confirm or correct my error in understanding?




At [this
link](https://www.jpf.go.jp/j/project/japanese/teach/tsushin/grammar/201103.html)
you can find a very good explanation, but it's only in Japanese.

Let me take out of that site the picture below and give a quick explanation.
First of all we can divide all the ways to express a judgement in three
groups:

  1. と思う、だろう、だろうと思う、かもしれない、にちがいない.
  2. そうだ（様態｛ようたい｝)、ようだ、らしい、そうだ(伝聞｛でんぶん｝）.
  3. はずだ、わけだ.

[![enter image description
here](https://i.stack.imgur.com/KKI6a.png)](https://i.stack.imgur.com/KKI6a.png)

This image belongs to Japan foundation: **「Copyright Japan Foundation」**

Basically the main difference is the degree of dependence that the speaker has
on the information. As you go from group 1 to 3, the degree of dependence on
the information increases. On the other hand, if you go from 3 to 1, there is
an increase in subjectivity on the judgment. That is, the speaker's subjective
judgement becomes stronger than the information. So not surprisingly this is
basically saying that the judgment is either objective or subjective depending
on whether the judgment itself is stronger than the dependence on the
information or the other way around. I realize this is probably more confusing
than helpful so let's look at some concrete examples as well:

Suppose you come back home and find the house messed up (open drawers, a
flower bin dipped over on the table etc). What would you say?

  * 泥棒に入られたかもしれない。 
  * 泥棒に入られたにちがいない。

These are from group 1: you think thieves came into your house but you don't
have enough confidence to state that clearly.

  * 泥棒に入られたようだ。
  * 泥棒に入られたらしい。

These are from group 2: your confidence that actually thieves broke into your
house is somewhat getting stronger. For example you noticed that jewels and
money are gone, and with this added information your imagination gets close to
conviction.

Suppose you also casually look at the window and notice that the glass is
broken. Then you have no doubt someone broke into your house and you would use
one from group 3 such as:

  * 窓が割れている。そうか、あそこから泥棒に入られたわけだ。

The article also goes on with another interesting example which I suggest you
read. If you do not understand it or feel this answer is still not clear
enough, please let me know and I will expand it.

**EDIT:** I got carried away with the general answer and forgot to mention
your specific case. Another common use of そう is when reporting not first-hand
information but rather something that was heard from a friend or the news. So
in the case of your plane そう is most likely used to indicate that such
information is coming from some other source (as it seems to be if as you say
they're likely to come from past statistics etc) rather than a direct
observation. However... if this was the case the construction would be "verb
(dictionary form) + そう" so it would be 混むそう. 混みそう indeed makes us think of
some impression of something that "looks crowded". Where is this sentence
coming from? Could it be a typo and it should actually be 混むそう instead of
混みそう? I realize now my answer might be off. Please leave a comment and if it
doesn't help or it's too off I'll remove it.

**EDIT 2** : So, I would say it this way. Suppose who wrote the news is
familiar with the information he/she is delivering (which makes sense). In
this case 混みそう is not wrong and I think it is a good choice because it
expresses, also according to
[this](https://japanese.stackexchange.com/questions/16312/difference-
between-%E3%81%9D%E3%81%86%E3%81%A7%E3%81%99-%E3%82%88%E3%81%86%E3%81%A7%E3%81%99-and-%E3%82%89%E3%81%97%E3%81%84%E3%81%A7%E3%81%99)
answer, a lower degree of certainty than ようだ. Besides, to the extent of my
knowledge ようだ expresses a speaker's subjective conjecture based on information
obtained through his/her sensory organs (hear, smell, touch etc). Not sure how
this is related in this specific case but also it seems that そう involves a big
degree of concern on the speaker's side while in the case of よう such degree is
lower. See for example see
[this](https://www.jpf.go.jp/j/project/japanese/teach/tsushin/grammar/201012.html)
page as well. Anyway, putting all these together makes me feel 混みそう is the
right choice here. About はず, I think it just doesn't work here, maybe it would
sound as "it should be crowded (according to my (the writer's) subjective
feeling rather than objective data).




At [this
link](https://www.jpf.go.jp/j/project/japanese/teach/tsushin/grammar/201103.html)
you can find a very good explanation, but it's only in Japanese.

Let me take out of that site the picture below and give a quick explanation.
First of all we can divide all the ways to express a judgement in three
groups:

  1. と思う、だろう、だろうと思う、かもしれない、にちがいない.
  2. そうだ（様態｛ようたい｝)、ようだ、らしい、そうだ(伝聞｛でんぶん｝）.
  3. はずだ、わけだ.

[![enter image description
here](https://i.stack.imgur.com/KKI6a.png)](https://i.stack.imgur.com/KKI6a.png)

This image belongs to Japan foundation: **「Copyright Japan Foundation」**

Basically the main difference is the degree of dependence that the speaker has
on the information. As you go from group 1 to 3, the degree of dependence on
the information increases. On the other hand, if you go from 3 to 1, there is
an increase in subjectivity on the judgment. That is, the speaker's subjective
judgement becomes stronger than the information. So not surprisingly this is
basically saying that the judgment is either objective or subjective depending
on whether the judgment itself is stronger than the dependence on the
information or the other way around. I realize this is probably more confusing
than helpful so let's look at some concrete examples as well:

Suppose you come back home and find the house messed up (open drawers, a
flower bin dipped over on the table etc). What would you say?

  * 泥棒に入られたかもしれない。 
  * 泥棒に入られたにちがいない。

These are from group 1: you think thieves came into your house but you don't
have enough confidence to state that clearly.

  * 泥棒に入られたようだ。
  * 泥棒に入られたらしい。

These are from group 2: your confidence that actually thieves broke into your
house is somewhat getting stronger. For example you noticed that jewels and
money are gone, and with this added information your imagination gets close to
conviction.

Suppose you also casually look at the window and notice that the glass is
broken. Then you have no doubt someone broke into your house and you would use
one from group 3 such as:

  * 窓が割れている。そうか、あそこから泥棒に入られたわけだ。

The article also goes on with another interesting example which I suggest you
read. If you do not understand it or feel this answer is still not clear
enough, please let me know and I will expand it.

**EDIT:** I got carried away with the general answer and forgot to mention
your specific case. Another common use of そう is when reporting not first-hand
information but rather something that was heard from a friend or the news. So
in the case of your plane そう is most likely used to indicate that such
information is coming from some other source (as it seems to be if as you say
they're likely to come from past statistics etc) rather than a direct
observation. However... if this was the case the construction would be "verb
(dictionary form) + そう" so it would be 混むそう. 混みそう indeed makes us think of
some impression of something that "looks crowded". Where is this sentence
coming from? Could it be a typo and it should actually be 混むそう instead of
混みそう? I realize now my answer might be off. Please leave a comment and if it
doesn't help or it's too off I'll remove it.

**EDIT 2** : So, I would say it this way. Suppose who wrote the news is
familiar with the information he/she is delivering (which makes sense). In
this case 混みそう is not wrong and I think it is a good choice because it
expresses, also according to
[this](https://japanese.stackexchange.com/questions/16312/difference-
between-%E3%81%9D%E3%81%86%E3%81%A7%E3%81%99-%E3%82%88%E3%81%86%E3%81%A7%E3%81%99-and-%E3%82%89%E3%81%97%E3%81%84%E3%81%A7%E3%81%99)
answer, a lower degree of certainty than ようだ. Besides, to the extent of my
knowledge ようだ expresses a speaker's subjective conjecture based on information
obtained through his/her sensory organs (hear, smell, touch etc). Not sure how
this is related in this specific case but also it seems that そう involves a big
degree of concern on the speaker's side while in the case of よう such degree is
lower. See for example see
[this](https://www.jpf.go.jp/j/project/japanese/teach/tsushin/grammar/201012.html)
page as well. Anyway, putting all these together makes me feel 混みそう is the
right choice here. About はず, I think it just doesn't work here, maybe it would
sound as "it should be crowded (according to my (the writer's) subjective
feeling rather than objective data).

