Analogical
Argument Homework
Modify the arguments in 8.7 into the longer form we discussed in class.
Step 1: If the correlation between the two properties in 8.7 was low, modify or replace Property 1 (i.e., the one cited in premise 1) to make the correlation high.
Step 2: Add a third premise describing the correlation between the two properties: If something has Property 1, how likely is it that it has Property 2? Make a wild guess how likely this is, stating it as a percentage.
Step 3: Add a fourth premise explaining why there is this correlation between the two properties, i.e., why it isn’t merely a matter of chance.
Example: 1. I am a human being and aspirin is a safe and effective pain medication for me.
2. Jane is also a human being.
3. There is a high correlation (95%) between the effects of a medication like aspirin and being a member of the same species. (Correlation)
4. This correlation makes sense since the effects of a medication depend on how it interacts with particular physiological features, and a creature’s physiological features are determined to a great extent by what type of species it is. (Explanation)
5. Therefore, aspirin will be a safe and effective pain medication for Jane.
Definitions:
(1) Correlation – The strength of the second analogy in the argument depends on whether the property at the basis of the first comparison (Property 1) is highly correlated with the property inferred in the conclusion (Property 2).
Besides changing the Property 1, the correlation can be increased by citing more things that share both properties, especially a diverse group of things, or by citing more properties that the things share in common which are highly correlated with the Property 2. It can be weakened by citing relevant differences, i.e., properties that are highly correlated with the property inferred in the conclusion that are found in the analogue but not the thing cited in the conclusion.
(2) Explanation – Whether there is a plausible explanation for the high correlation of these properties.