Why is it that transitive seeming expressions like 蜘蛛の子を散らす and 波を打つ act intransitive


I can partly understand 波を打つ but the only thing I don't understand is how
hitting the waves would cause undulation or resemble it, but I don't
understand how 蜘蛛の子を散らす is intransitive. You're not the spiders being
scattered, you're the scatterer. So why does it mean to scatter in all
directions like baby spiders? You don't scatter to scatter baby spiders...




Both 散らす and 打つ are transitive. So, theoretically, once they have an object
such as 波 or 蜘蛛の子, they no longer take an additional one: they are now
intransitive.

波を打つ can be seen as an example of 結果の目的語. It is a phenomenon that the direct
object (marked with the particle を) is not actually a recipient of the action
but a result of it. The most famous example is that "to boil water" is rarely
expressed as 水を沸かす but almost always as 湯を沸かす. (This kind of direct object can
be seen also in English. e.g. "dig a hole" used to mean "dig ground and/to
make a hole") So here, 波を打つ means the subject (ocean, lake etc.) beats
something and it results in waves.

蜘蛛の子を散らす is almost always followed by the auxiliary verb "よう(だ)" and depict
the state of people going/getting/running away in all direction. One never say

> 彼らは蜘蛛の子を散らした。

as an idiomatic sense, but say

> 彼らは蜘蛛の子を散らしたように逃げた。




Both 散らす and 打つ are transitive. So, theoretically, once they have an object
such as 波 or 蜘蛛の子, they no longer take an additional one: they are now
intransitive.

波を打つ can be seen as an example of 結果の目的語. It is a phenomenon that the direct
object (marked with the particle を) is not actually a recipient of the action
but a result of it. The most famous example is that "to boil water" is rarely
expressed as 水を沸かす but almost always as 湯を沸かす. (This kind of direct object can
be seen also in English. e.g. "dig a hole" used to mean "dig ground and/to
make a hole") So here, 波を打つ means the subject (ocean, lake etc.) beats
something and it results in waves.

蜘蛛の子を散らす is almost always followed by the auxiliary verb "よう(だ)" and depict
the state of people going/getting/running away in all direction. One never say

> 彼らは蜘蛛の子を散らした。

as an idiomatic sense, but say

> 彼らは蜘蛛の子を散らしたように逃げた。

