The phrase "are unsound" is correct and usable in written English.
It can be used to describe something that is not based on sound reasoning, logic, or evidence, often in a critical context.
Example: "The arguments presented in the debate are unsound and fail to address the key issues at hand."
Alternatives: "are flawed" or "are invalid".
Fiscal, tax, and regulatory policies are unsound and not oriented toward growth and efficiency.
Economically, very high buildings are unsound because too much of their core must be wasted on elevators, utilities & other non-revenue producing necessities.
IN A complaint filed last week, the NAACP Legal Defense Fund charged that the admissions procedures of Stuyvesant High School and other specialised high schools in New York City are "unsound and discriminatory" because the Specialized High School Admissions Test (SHSAT the sole factor in admissions has yielded striking racial imbalances in the schools' student bodies.
This seems plausible, but in 2010 two mathematical biologists, Martin Nowak and Corina Tarnita, and I demonstrated that the mathematical foundations of the kin selection theory are unsound, and that examples from nature thought to support kin selection theory are better explained as products of multilevel selection.
The government's line is that the Old City is too far away from adequate water for putting out fires, and that the structures are unsound given the numerous earthquakes that regularly strike the region – although the fact that so many of the Old City's buildings are still standing is testament to their ability to withstand most of what nature can throw their way.
The assumptions on which the ESA was founded in 2008: that the caseload was too high; that incapacity benefit was too easily accessible; that there were people claiming IB who weren't ill enough to merit it; that work is pretty much universally "good for you" are unsound.
