The existing works of ancient literature, science, and philosophy do not represent the most original work produced in ancient times.
Conclusion
The existing works of ancient literature, science, and philosophy don't represent the most original work produced in ancient times.
Evidence
The existing works frequently refer to other works that we no longer have.
Evaluate
On most Principle-Strengthen questions, we're just looking to build a linking idea from Evidence to Conclusion.
The Evidence here is that , and the Conclusion is . The author must be assuming that these other works, the ones cited, the ones we don't have, are actually the more original works.
Goal
Look for an answer saying something like, . We need to connect the ideas of with .
Something like would also work.