Opinion

[parisielvirac]

Why should we look out for opinion vs facts? are opinions true? the on demand video does not explain well.

[Rachael Wilkenfeld]

Hi parisielvirac,

Usually the importance of noting fact/opinion is noticing when the author changes from facts in the premises to an opinion in the conclusion or vice versa. Let's see why it's a problem.

Imagine the following argument structure.
Premises: The octopus has 9 brains, 3 hearts, and blue blood. It can camouflage itself. It can open jars, and jump out of the water to catch prey.
Conclusion: The octopus is the most fascinating animal in the sea.

Premises there were all facts. That conclusion was an opinion. No matter how interesting the facts are, they gave us no support for the opinion based conclusion. We don't know if the facts given are fascinating, or if other animals would be similarly fascinating. The fact based premises don't lead to the opinion conclusion.

It works the other way too.

Premises: Delivery companies should pay their employees for all hours worked. To do otherwise would be to steal from their employees' pockets. Theft is wrong.
Conclusion: Delivery companies pay their employees for all hours worked.

We can't jump from how something should be to how something is. We don't know if the companies agree with those opinions, or if they would behave in accordance with those opinions even if they agreed with them. The opinion premises don't let us draw a conclusion about facts.

Hope those examples help.

[parisielvirac]

sure they help. but I don't fully understand your second example, can you give me another one?

And how should I use this information when answering the questions? Not consider the opinion provable so it shouldn't be reinstated in must be true questions?

Thanks

[Adam Tyson]

The idea here is that if all we have in the premises are opinions, they will not support a fact-based conclusion, and vice versa. You cannot use evidence about what is good or what should be true to prove what will happen or must happen. You cannot use evidence about what must or will occur to prove what should occur. It's not a question of whether the opinions are "true," but about what kind of things you can and cannot prove based on those opinions.

Here's another example:

People ought to treat their neighbors with kindness and respect. Betty and John are neighbors, so Betty is obviously kind to John.

The premise here is an opinion about what ought to be the case. The conclusion is a fact that is not proven by that opinion. Maybe Betty ought to be kind, but that doesn't prove that she is kind. Maybe she doesn't do what this author thinks she ought to do?

Or try this one:

You prefer pizza to tacos, so since you are hungry right now you will certainly get a pizza instead of tacos.

Again, just because you have a preference (which is a form of an opinion) I cannot use that to prove what action you will take. Maybe there is no pizza available, but you are standing in front of a taco truck? Maybe you love tacos, and despite your general preference for pizza you will choose tacos on this occasion?

Match the type of evidence to the nature of the conclusion, as well as matching the strength of the evidence to the strength of the conclusion. You cannot use evidence about what could occur to prove what will probably occur or what will certainly occur. Just because you could get a pizza doesn't mean you probably will, or that you certainly will.

[parisielvirac]

got it! thanks so much