As opposed to the reading which claims that there are three theories about how agnostics may have lived, the lecture question that after reasonable inference, they have problems.

To start with, the reading deems that agnostics couldn't hunt arthropods. because they without large well developed eyes, even some species completely blind, to find and hunt arthropods. Consequently, they are not free-swimming predators. It would had some other special sensory organ to find their prey. By comparing the views of both parties , the lecture casts doubt on the first point in the reading.

Besides, the second point in the reading is again questioned by the lecture, which assert that the agnostics couldn't live at the bottom of the sea , since their fossils have been found around the world, and seafloor dwellers move slowly across the sea floor and stay in localized areas rather than spreading to new areas. Plus, agnostics haven't the ability to move very far across the sea floor since multiple geographic areas spread across large distance.

Finally, although the reading suggests that the agnostics were parasites,  the lecture still challenges it by pointing out the number of agnostics. The lecture proposes that there are too many parasites would kill their host organism and we have been found a large of fossils .