The phrase "an unknown purpose" is correct and usable in written English.
It can be used when referring to a goal, intention, or reason that is not identified or understood.
Example: "The artifact was discovered in the ruins, but its unknown purpose has puzzled researchers for years."
Alternatives: "an unclear intention" or "a mysterious aim".
Aforementioned Whisper brings random strangers together for an unknown purpose.
They are there, sitting like small squiggles on a startling sonata, with an unknown Purpose.
There was a TV, VCR, DVD player, cable box, karaoke player for his songbird sister, some converter with an unknown purpose -- all linked by various cables.
The works of Sextus Aurelius Victor and Eutropius, who ably abridged earlier historical works, are fairly accurate and more reliable than the Scriptores historiae Augustae, a collection of imperial biographies of unequal value, undoubtedly composed under Theodosius but for an unknown purpose.
A witch has a giant device that squashes up human bodies for an unknown purpose.
The aliens have captured the human crew for an unknown purpose.
If a gene with a previously unknown purpose appears active in a part of the brain responsible for mood, for example, then it becomes a target for manic depression and other mood disorders, Dr. Boguski said.
While we speak, envious time will have already fled: seize the day, trusting as little in the next day!" "I feel as if I was born for this end, this was my fate from birth, and there is a greater unknown purpose which was meant for my life which no one may ever figure out.
Designed by the legendary firm of McKim, Mead & White, board officials said the headquarters was originally three buildings -- an Elks lodge, a courthouse and a third of unknown purpose -- that were built in the 1920's for $6 million.
His horoscope is identical to mine but we're so different, I had a ready-made control.' But conclusive proof came when he was travelling to the BBC for a meeting of unknown purpose, picked up a newspaper in the Tube and idly flicked through his horoscope.
In Wallinger's own 2011 Shadow Walker, there is a sense of unknown purpose, the shadow walking as though on a gym machine with the paving slabs sliding away beneath him.
