The phrase "defend the validity" is correct and usable in written English.
You can use it when you want to express a need to protect or prove the accuracy of something. For example, "The lawyer had to defend the validity of his client's testimony in court."
Instead of having to prove TKT infringed, she said, Amgen will now only have to defend the validity of its patents.
In essence, Messrs Card and Krueger defend the validity of their earlier work; in essence, Messrs Neumark and Wascher still think it wrong.
Forums like the AEA meetings, where economists are forced to defend the validity of their research against their peers' attempts to poke holes in it, are another vital way to ensure that economic research is credible, robust and valid.Faith or failure?Some argue that economists face greater ethical questions than those about financial conflicts of interest.
Again, this amounts, for the challenger, to accepting the burden of the formal restriction in a subdialogue where he will defend the (validity of the) formula.
Strawson therefore holds that it is myth to suppose that we can locate a level of claim on the basis of which we can defend the validity of our application of physical object concepts.
So when advances in science or medicine call those traditional norms into question, fundamentalists are forced to challenge the advances in order to defend the validity of their religious beliefs.
Both parties had observers in each county, inspecting ballots and raising objections to some, while defending the validity of others.
Although he strongly condemned the purchase of office by clergymen, Damian defended the validity of the sacraments they administered.
The guests strongly defended the validity of existing international law; the Israelis claimed that in order to fight terrorism effectively, it should go certain changes.
In his response, Jerusalem, published in 1783, Mendelssohn defended the validity of Judaism as the inherited faith of the Jews by defining it as revealed divine legislation, and he declared himself at the same time to be a believer in the universal religion of reason, of which Judaism was but one historical manifestation.
