Which of the following is an example of deductive reasoning?
A. Every house we have lived in has been built after 1980, so the next house we live in will likely have been built before 1980.
B. All the houses in my neighborhood were built after 1980, so the houses on the next street over will have been built after 1980.
C. All the houses in my neighborhood were built after 1980, so the houses on the next street over will have been built before 1980.
D. Every house we have lived in has been built after 1980, so the next house we live in will likely have been built after 1980.
The Correct Answer and Explanation is :
The correct answer is D: “Every house we have lived in has been built after 1980, so the next house we live in will likely have been built after 1980.”
Explanation of Deductive Reasoning
Deductive reasoning is a logical process in which a conclusion is drawn from a set of premises. In this type of reasoning, if the premises are true, the conclusion must also be true. It follows a specific structure where general statements lead to a specific conclusion. The classic form of deductive reasoning can be illustrated by the syllogism:
- Premise 1: All humans are mortal.
- Premise 2: Socrates is a human.
- Conclusion: Therefore, Socrates is mortal.
In option D, the reasoning process is straightforward: it starts with the general premise that all houses the individual has lived in were built after 1980. The conclusion drawn from this premise is that it is likely the next house will also be built after 1980. This maintains a logical consistency, as it applies a general observation to a specific case.
The other options demonstrate flaws in reasoning:
- A suggests the next house will likely be built before 1980, which contradicts the premise and is an example of an incorrect inference.
- B assumes that houses on the next street will also follow the same building trend as the neighborhood, which lacks evidence; it’s an assumption rather than a logical deduction.
- C contradicts the information given, suggesting houses built on the next street will be older, which does not logically follow from the premise about the neighborhood.
Thus, option D clearly exemplifies deductive reasoning, as it adheres to the logical structure where the conclusion is directly supported by the given premise.