As opposed to the reading which claims that there are three theories about how agnostics may have lived, the lecture question these theories, with the reasons as follow...

To start with, the reading deems that agnostics may have been free-swimming predators that hunt smaller animals, because other types of primitive arthropods were strong swimmers and active predators. On the contrary, the lecture asserts that agnostics have not large well developed eyes and there is no clear evidence in the fossil record that agnostics can catch prey. By comparing the arguments on both sides , 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 reckons that the idea that agnostics live at the bottom of the sea is wrong, since seafloor dwellers move slowly across the sea floor and stay in localized areas rather than spreading to new areas. Plus, agnostics may not have the ability to move very fast or very far across the sea floor since multiple geographic areas spread across large distance.

Finally, although the reading suggests that the agnostics are parasites, living on and feeding off larger organisms, the lecture still challenges it by pointing out the viewpoint is wrong. The lecture proposes that there are too many parasites and they would kill off the host organism they live on.