Would harvesting the yews have far-reaching environmental repercussions?

Derek:❓

Lola: ✅

Lola says yes (or at least possibly yes), but Derek is silent on the subject. If anything, he concedes at least some environmental repercussions.

Should effective drugs be based on synthetic chemicals?

Derek:❓

Lola: ❓

If (B) asked whether the anticancer drugs we use in the short term should be based on synthetic rather than naturally-occurring chemicals, we’d be getting somewhere. But (B) is a statement about effective drugs in general. Neither speaker takes a stance on this general claim.

Should we wait for synthetic drugs even though we can make yew-based drugs now?

Derek: ❌

Lola: ✅

Derek thinks we shouldn’t wait. Lola thinks we should.

Would the environmental disaster be really extensive?

Derek:❓

Lola: ✅

Lola says yes, but Derek is silent on the subject. If anything, he concedes at least some environmental repercussions (although he never discusses the owl).

Should environmental considerations ever have any weight?

Derek:❓

Lola: ✅

Lola’s position implies she thinks the answer is yes – she bases her “we should wait” position on environmental considerations, so she must think they have weight.

Derek is silent because (E) is quite a weak claim, so disagreeing with it would mean taking the very strong position that “no environmental considerations should ever have any weight when human lives are at stake.” We have evidence that Derek thinks these environmental considerations are outweighed by other, more important considerations, but that’s a much weaker position.

If anything, Derek concedes the relevance of at least some environmental considerations.