Loading...
It is said of parasitic forms of life that, although they burden their hosts, they do not kill them, since a parasite cannot survive unless its host does. Mr. Craig's prize-winning lilies, however, were invaded by dodder, a parasitic plant, and every one of the lilies died soon after. Plainly, therefore, a parasite can be deadly.
The argument above depends on which of the following assumptions?
| Text from Passage | Analysis |
| It is said of parasitic forms of life that, although they burden their hosts, they do not kill them, since a parasite cannot survive unless its host does. |
|
| Mr. Craig's prize-winning lilies, however, were invaded by dodder, a parasitic plant, and every one of the lilies died soon after. |
|
| Plainly, therefore, a parasite can be deadly. |
|
The argument starts with a widely accepted principle about parasites, then presents a specific counterexample involving lilies and dodder, and concludes that the general principle is wrong.
A parasite can be deadly (can kill its host).
The author uses one specific case (lilies dying after dodder invasion) to challenge and overturn a general biological principle. The logic assumes that the lily deaths were actually caused by the dodder parasite, rather than by some other factor.
Assumption - We need to find what the author must believe to be true for their conclusion to logically follow from the evidence
The conclusion makes a broad claim about parasites in general ('a parasite can be deadly') based on one specific example (dodder killing lilies)
To find the assumption, we need to identify what could falsify the conclusion while respecting the facts. The author sees lilies died after dodder invasion and concludes parasites can be deadly. But what if something else killed the lilies? What if dodder isn't actually a parasite? What if the lilies were already dying? We need to find what the author must assume to make this logical leap from one example to a general conclusion about parasites.