WeightliftingThinker wrote:How do you apply the Assumption Test to a conditional?
Moreover, how do you apply it to a sentence that has phrases like "less likely," "more likely," etc.?
When negating for necessary assumptions, you're trying to find the relative opposite, not the polar opposite.
e.g. "I always go to the club when I get my paycheck"
Relative opposite: "I don't always go to the club when I get my paycheck"
Polar opposite: "I never go to the club when I get my paycheck"
Like someone else mentioned, I think adding a "no" or "not" is the easiest way to think about this. So 'less likely' just becomes "not less likely," and so on.
This only works for necessary assumption questions. If you negate one and it breaks the argument, then it must be a required assumption to allow for that conclusion. Sufficient assumptions guarantee the conclusion, but their absence doesn't necessarily break the argument, so this won't work there.
e.g.:
Premise: Pizza is delicious. When I eat delicious things, I am happy.
Conclusion: I am happy.
Sufficient assumption: I am eating pizza.
If we negate this, it becomes "I am not eating pizza." But that doesn't necessarily mean that I am not happy - we never established that eating delicious things was the
only way for me to be happy, so this doesn't break the argument. It is sufficient, but not necessary.
Now let's take a necessary assumption. There are many possible ones, but let's look at the following: "I am capable of feeling emotions."
If we negate this, it becomes "I am not capable of feeling emotions." If this were true, then there's no way I'd be able to be happy, so as obvious as this statement sounds, it is a necessary assumption.
Hope that helps!