知る由もない

しるよしもない

to have no way of knowing; to be completely ignorant of

Also written 知る由も無い、知るよしもない、知るよしも無い

Meaning

expadj-i
to have no way of knowing; to be completely ignorant of

Example sentences

彼がどこへ行ってしまったか知る由もない。

There is no way of knowing where he's gone.
何が起こるか知る由もない。

There is no knowing what may happen.
私たちは何をなしたのかを知ることはできても、それを変えることはできない。そして未来は変えることができるが、なにをなし得るかについては知る由もない。

It is possible for us to know what has been achieved in the past, but it is not possible for us to change it. And it is possible for us to change the future, but it is not possible for us to know what will be achieved in it.