@oristarA,
oristarA wrote:Quote:And where the negative impact derives from criticisms of questionable scientific merit, that can only be considered good science — and common sense.
I think "that" here should refers to
"where the negative impact derives from criticisms of questionable scientific merit."
I agree.
oristarA wrote:That is: "that" here serves as the equivalent of "which."
It doesn't sound right:
"And where the negative impact derives from criticisms of questionable scientific merit,
which can only be considered good science — and common sense."
However, if you swap "it" for "that", the sentence will still make sense.
"And where the negative impact derives from criticisms of questionable scientific merit,
it can only be considered good science — and common sense."
Using "that" as a substitute for "which" would be "definition 4" in the pronoun section here:
http://oxforddictionaries.com/definition/american_english/that
Quote:4 (plural that) [relative pronoun] used to introduce a defining or restrictive clause, especially one essential to identification.
instead of “which,” “who,” or “whom”:
the book that I’ve just written
instead of “when” after an expression of time:
the year that Anna was born
However, I think they are using "definition 2" in the pronoun section.
Quote:2 referring to a specific thing previously mentioned, known, or understood:
that’s a good idea
what are we going to do about that?