PHL 3000 Lecture Notes - Lecture 2: False Premise, Mattress, Hemoglobin
Module 2
Basic Concepts – Reading Notes
Arguments, Premises, and Conclusions
• Logic: the organized body of knowledge, or science that evaluates arguments.
o The study of logic is an increase in confidence that we are making sense when we
criticize the arguments of others and when we advance our own arguments
• Argument: a group of statements, one or more of which (premises) are claimed to provide
support for, or reasons to believe, one of the others (conclusion).
Lecture 2.1
What is an Argument?
• Common misconceptions:
o An argument is nothing more than disagreeing with another person
o Winning an argument is simply a matter not agreeing with your opponent
o It is rude to argue with another person—nice people don’t argue
• An argument is a set of statements, at least one of which is meant to provide rational
support, or a reason to believe, one other statement
o Statement: any sentence that is capable of being true or false
▪ Not all sentences are statements (i.e.: questions, commands, exclamations)
• Premises
o The statements in an argument intended to provide rational support, or a reason to
believe, the other statement’
• Conclusion
o The statement in an argument that is rationally supported by the premises
The Purpose of an Argument
• An argument is meant to provide a reason to believe a statement that, prior to the
argument, was not known to be true, or was not full justified before the argument
• In an argument, we move from the things we already know, or have good reason to
believe (the premises) to something that was not known before
o Yield new knowledge
• All arguments make two claims:
o Claim 1: The premises are true (or acceptable) -fact
o Claim 2: The premises support the conclusion -connection
▪ If the premises are true the conclusion is true
• Two ways to evaluate an argument:
o Evaluate the truth or acceptability of the premises
o Evaluate whether the premises really dos support the conclusion
Evaluating Premises
• If a premise is false, it provides no support for the conclusion, and hence is unacceptable
• However, not all true premises are acceptable
o Premise 1: god exists
o Premise 2: god does not exist
▪ One has to be true. But we don’t know which so it is not good for
argumentation.
find more resources at oneclass.com
find more resources at oneclass.com
o The problem with these two premises is that they are both very controversial, and
would most likely not be accepted by many people in the audience
▪ Need to rationally convince people that your conclusion is true
• The more controversial a premise is, the less acceptable it is
• How controversial a premise is depends on the target audience
o “Evolutionary theory is largely correct” is not a controversial premise at a biology
conference, but it is to creationism
• When confronted with an argument you do not agree with, do not simply deny the
conclusion
o You must respond to the reasons that are provided for the conclusion
o Ask: are premises acceptable?
o Ask: if the premises were acceptable, would the conclusion follow?
Lecture 2.2
Identifying arguments
• Keep the purpose or function of an argument in mind when trying to identify them and
distinguish them from non-arguments
o If the purpose of an argument is to provide rational support for a statement, then
when trying to identify an argument, ask whether or not the author of the passage
is trying to prove that something is true
• Sometimes, the author will provide clues that the passage is an argument by using words
that indicate that a statement is meant to be a premise (premise indicators)
o Since…
o Given that…
o …for the reason that…
o … may be inferred from
• Sometimes, the author will provide clues that the passage is an argument by using words
that indicate that a statement is meant to be a conclusion (conclusion indicators)
o Therefore…
o Thus…
o Consequently…
o For this reason…
• Some passages look like arguments, but are not:
o You should put on a coat because it is cold outside
▪ Argument: one is a premise for the conclusion
o The water froze because it was so cold last night
▪ Not an argument: not trying to convince you of something
o Is the author trying to prove something?
• Passages without arguments:
o Warnings
▪ You better study for that test
▪ Watch out for the pothole
• If no reason is given, then it is not an argument
o Pieces of Advice
▪ When studying logic, it is best to do a little bit each day…
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The purpose of an argument: an argument is meant to provide a reason to believe a statement that, prior to the argument, was not known to be true, or was not full justified before the argument. If the premises are true the conclusion is true: two ways to evaluate an argument, evaluate the truth or acceptability of the premises, evaluate whether the premises really dos support the conclusion. If a premise is false, it provides no support for the conclusion, and hence is unacceptable: however, not all true premises are acceptable, premise 1: god exists, premise 2: god does not exist, one has to be true. I don"t think she is that nice: stating a belief without providing a reason to believe it is not an, loosely associated statements argument, eggs can be used as a main ingredient in a dish. I ate way too much; therefore, my stomach hurts: use conclusion indicators, not trying to prove something.
