MODULE LESSON 7 - APHI 221 – Philosophical Perspectives on Communication – Mrs AC Austin
Ep 1.4 Transcript (Center for Innovation in Legal Education)– Premises and Conclusions –
0:00 Evaluating Premises and Conclusions: An Overview.
0:03 So far ,you know that arguments are made up of a conclusion and the premises offered to defend or uphold it. Some arguments are deductive, that is, if the premises are true and the former the argument is valid, then the conclusion has to be true and the argument is sound.
0:23 Other arguments are inductive. In an inductive argument if the premises are either true or at least acceptable, remember that means that their relevant to the issue at hand and provide sufficient justification, then the conclusion is likely to be true and we consider these inductive arguments to be strong
0:43 In questioning both types of arguments there are a number of evaluations you can make to determine the soundness or strength up the argument in this module you learn about two main ways to evaluate an argument first you'll hear about how to evaluate premises in and of themselves on their own merits then you learn how to evaluate the logical link that connects the premises to the conclusion
1:10 This module provides an overview of the key evaluation approaches you should use to assess
any argument you encounter later modules will dig deeper into each approach and explain how you can effectively use the techniques to evaluate different types of arguments
1:26 EVALUATING PREMISES TRUTH AND ACCEPTABILITY
Premises supply the evidence on which an argument is based and their strength can range from the strongest premises that are straightforward facts such as the Earth revolves around the Sun to weaker premises.
My personal opinions are value judgments – that can be like your friend saying “This music is awful”. One standard for evaluating a premise is to determine whether it's true or false.
1:54 We can use observed or empirical evidence, that is things we see touch hear smell taste and so on 1to figure out whether certain kinds of premises are true. Now it may not be easy to determine the truth of a premise. For a lot of early human history proving that the earth revolved around the son was quite difficult but we at least know how we're supposed to go determining its truth, which means proving or disproving the premise. Sometimes while it may be possible in theory to actually observe the truth to the premise it may be, practically speaking, impossible to do so - for example - take the claim that all swans are white. In order to definitively prove this to be true we would be defined every single Swan on the planet to see what colour it is - a daunting task, especially considering more swans are being born all the time. However we could rely on Swan experts conducting research involving as many Swan as is reasonable and investigating all aspects of swan biology to tell us an experts view on swan colour. While we wouldn't prove that the premise was true,
we could judge it to be more or less acceptable.
3:07 In addition to hard to prove empirical claims there are other premises that cannot be evaluated on whether they're true or not. Premises that relate to aesthetic moral or ethical claims fall in that category. Opinions in value judgments represent personal cultural communal social and religious perspectives and beliefs. These by their very nature cannot be proven or disproven, however that does not mean that they cannot or should not be subjected to scrutiny and evaluation to determine whether they provide acceptable reasons for agreeing with the particular argument.
3:47 Throughout your personal academic and professional life you grapple with the number of arguments based on opinions or value judgments, you should resist the temptation to simply say “well everyone's entitled to their own opinions” and to accept all such argument is equally plausible. There are many important issues and problems about which which you'll find serious disagreement.
4:09 Critical thinking is meant to arm you with the tools and resources to carefully consider those arguments, assess the relative strengths and weaknesses and come to an informed and considered opinion of which one you believe to be true or reasonable.
4:25 RELATING PREMISES AND CONCLUSIONS – VALIDITY, RELEVANCE AND INSUFFICIENCY
4:29 It's not enough to simply evaluate individual premises to determine their truth or acceptability, consider the following argument: “The sky is blue, therefore I should wear sunglasses when I'm outside!”. Now it is true that the sky is blue, but a reasonable person might wonder what in the heck does the sky being blue
have to do with wearing sunglasses? The truth of the premise does not necessarily guarantee that you're dealing with a valid argument. Instead consider an argument that says: “the Sun is bright I should make sure to wear my sunglasses today”. Now this argument seems much stronger and it is stronger because
1) the premise is or can be determined to be upon visual examination true and
2) there's a reasonable connection between brightness and the wearing of sunglasses. Remember that deductive arguments are those were the truth to the premise can lead to a valid conclusion so when evaluating deductive arguments you should look for whether the former the argument is valid.
5:36 A deductive argument has a valid form if it is impossible for the premises to be true and the conclusion to be false so to illustrate this, consider an example of an argument with an invalid form: Your friend tells you the old business building is worn out and it's unsafe so we should tear it down for the safety of the students.
5:58 While the premise is that the building is old and unsafe are true they don't necessarily lead to the conclusion that the building has to be torn down. One obvious alternative is that repairs could be made to make the building safe. In this case even though the premise is true it's still possible for the conclusion to be false because it's not necessarily related to the premise.
6:22 Now think about this alternative example that has a valid form: Your friend says the old business buildings are unsafe because it doesn't have a fire alarm system, which makes it unsafe so we should install a fire alarm system for the safety of the students. Here clearly if the premise is true then the conclusion
must also be true. For inductive arguments two separate standards must be used to evaluate arguments logical validity, relevance and sufficiency. Instead of the true or not standard used for deductive arguments. Inductive arguments rely more or less on acceptable premises to make them stronger or weaker. This makes the relationship between the premises and conclusions much more complicated. It's not the case that a premise you judge to be true can serve on its own to defend a conclusion. Instead you're dealing with premises that are often opinion rather than fact and these premises have a range in their acceptability.
7:24 So one thing you must do in evaluating an inductive argument is to first figure out if the premises are relevant to the issue at hand and the conclusion that strong. Imagine your professor asked the class: “Should I hold a review session before the midterm exam?” Your classmate responds by saying: “No you shouldn't, the text book for this class was really expensive now the claim that the textbook was expensive may be a perfectly acceptable claim but it doesn't have anything to do with the conclusion that there should not be a review session! Consider an alternative response: “No you shouldn't, my friends are in the other section in this class and they aren't having a review session, I don't think it would be fair if we have one.
8:10 In this case you will still want to evaluate the acceptability of the premises about fairness but it is clear that there is a connection between the premises and the conclusion. In addition to figuring out whether the premises are relevant you must also assess whether they are sufficient that means you must think about whether the claims made premises or enough to justify the conclusion.
8:34 Let's go back to the second response on the midterm review question -the one we're classmate says “ no we shouldn't my friends in the other section and they are not having a review session.” Let's say you determine the following things
1) if it is true that the other section is not having a review?
2) is fairness between sections is a reasonable and acceptable thing to be concerned about ?
3) is what's happening in the other section is relevant for your class?
9:01 So is that it? Do you accept your classmates argument is strong enough or might you instead say: “well I see your point it is important to be fair and I feel bad that the other class won't get to have a review but why should we suffer too - that's not a good enough reason”. Essentially you're saying that your classmates premises are not sufficient reasons to accept his conclusion that is it's not enough to justify the conclusion.
9:29 Now you should have some idea of how to go about evaluating deductive and inductive arguments - you should examine the premises themselves and try to determine whether they're true and acceptable then
you need to consider the connection between premises and conclusions are the premises relevant to the issue and the conclusion reached or the sufficient to justify that conclusion. Knowing to ask these questions
9:53is an important step in critical thinking. In later modules you learn more about how to answer these questions.
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Exercise: Evaluate the following arguments, state whether they are deductive or inductive arguments, and if they are valid, sufficient and relevant.
- · The CEO of this company has taken money collected by the staff for improvements to the staff rest area, and used it build himself a big, fancy and luxurious office. He has fired the staff who have questioned his misbehaviour. He has replaced the fired staff with his family members who stand to gain luxurious offices of their own. The CEO will enrich and benefit himself now without any interference from the staff representatives. Therefor we should stop him and vote to remove him from office.
- · It’s dangerous to walk alone at night. Daytime social events are boring. During the day you can really take a good look at the beautiful surroundings.
- · The streets are wet outside, if the streets are wet it probably indicates the possibility of rain. I should take my raincoat and wear gumboots.
- · Bread causes cancer. My aunt had cancer, she ate bread. Therefore Bread causes cancer.
- · You say: “You shouldn’t take the MMS Supplement, it asks you to mix chlorite with an acid solution such as citric acid – this produces a mixture called chloride dioxide. Chloride Dioxide is the chemical name for bleach. You are literally and willingly drinking bleach when you take the MMS supplement. Bleach is toxic and it will make you sick.” Your friend answers you with this argument: “Andrew the physiotherapist takes MMS, so do I and so does my friend Colleen”
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