Final answer:
A weak assertion is a sentence that uses evidence too weak to firmly establish a conclusion, often due to fallacies of weak induction, sloppy associative reasoning, or letting emotion overrule reason.
Step-by-step explanation:
The underlined sentence in a paragraph might be considered a weak assertion if it relies on evidence that does not firmly establish a conclusion. This weakness could stem from the use of evidence that is inconclusive or irrelevant, thereby leading to a fallacy of weak induction. Such a sentence would fail to provide a reason for the topic sentence's claim, an illustration of the topic sentence's point, an explanation of the sentence's point, or evidence demonstrating the topic sentence's point.
For instance, if a paragraph's topic sentence makes a claim about the effectiveness of a policy without providing clear examples or statistical evidence, this would be a weak assertion. The writer might be using sloppy associative reasoning or letting emotion rule over reason, allowing subjective or tangential aspects to influence the logical strength of the argument. It is important to distinguish between the arguer's personal characteristics and the merits of the argument itself.