Here are examples of the word/phrase "inscrutably" used in a sentence and paraphrased in a sentence...
There is no scientific explanation for how that object inscrutably appeared out of no where.
There is no scientific explication for how that object mysteriously appeared out of no where.
In regards to how the world was created, the professor said it was done inscrutably.
In regards to how the world was created, the professor said it was done cryptically.
Other Examples...