What term refers to comparing two fundamentally different entities to argue a point?

The term referring to comparing two fundamentally different entities to argue a point is indeed "Weak Analogy." This concept arises when an argument relies on an analogy that is not strong enough to support the conclusion drawn from it because the items being compared are not sufficiently similar in relevant ways.

For instance, if one were to argue that because a car and a bicycle both have wheels, they are similar in other aspects, this would be a weak analogy. The important differences between the two—such as their function, mechanics, and the context in which they are used—make the analogy inadequate for supporting a strong argument.

Understanding weak analogies is crucial, especially in reasoning, as it aids in evaluating the strength and validity of arguments. In contrast, other terms like False Dilemma, Slippery Slope, and Post Hoc Fallacy describe different types of logical fallacies that do not specifically involve the comparison of fundamentally different entities.