Notes from class on January 10th, 2012 / Christina Appleby
Methods in Philosophy:
-critical (reconstruction of arguments)
-speculative (determining whether or not it is valid/evidence based)
Tools that a philosopher has:
-reasoning (all human beings have this capacity. Any claim made by a philosopher
has to be proven or shown so that it is publicly accessible knowledge and
somebody else can believe it)
-Publicly accessible evidence (everybody, in principle, should be able to
acquire the knowledge about these claims. Ex: There are tables in the next
room. How do you know? Anyone can go look for themselves; therefore – publicly
*private beliefs or ideologies cannot be used in arguments because nobody
else can find out about it or gain evidence that it is true. Examples or
private beliefs are things like dream, inklings, or even “I swear I have
X-ray vision!” Private beliefs are necessarily wrong; they just can’t be
used in philosophy because they have no grounds for truth.
Recap: Philosophy has basic tools like reasoning, thinking and drawing on
Logic: important when using reasoning.
What makes an argument logical?
-content (data, observations, truth)
-form (how is the evidence going to make it plausible? How is it organized
to prove the conclusion?)
Examples of argument:
If Chennai is in Tamil Nadu, then it is in India.
Chennai is in Tamil Nadu.
Therefore, Chennai is in India.
If these two statements are true, then the conclusion in true.
If it is raining, then I will get wet.
It is raining
I will get wet.
The form allows the premise to relate to the conclusion. It provides evidence.
If suspect’s DNA is found at the crime scene, then the suspect was involved
in the crime.
The suspect’s DNA was found at the Crime scene.
The suspect was involved in the crime.
These arguments look like this…
If A, then B.
All the content has been removed from this logic. It focuses entirely on
structure and format of the argument. It still remains valid.
*observations by themselves cannot tell you about values or judgments of
I didn’t sleep a wink.
(this sentence is metaphorical and vague)
In order to be clear, the metaphorical and vagueness must be removed, so
that the content is easily understood.
Therefore, statement means (in a very formal way) that all humans must be
This type of logic is called Formal Logic. We won’t be focusing on it in
class. We will be looking at the other type of logic called, Informal Logic.
This may be a test question. What is the difference between those two kinds
Formal logic- focuses on form and structure.
Informal Logic- focuses on content.
What is an Argument? (see link for a laugh >> http://www.youtube.com/watch?v=kQFKtI6gn9Y
Arguments can be the conflict of opinions
But in philosophy…
An argument is a “connected series of statements designed to establish another
Or “A set of statements in which it is claimed that one is supported by others.
The statement, “The Montreal Canadians are the best hockey team.” Has no
reasons or evidence. It is just a conclusion.
Questions to think about for next class:
1. What is a premise?
2. How can I distinguish between what is an argument and what is just
a collection of opinions?
January 12th, 2012 / Jocelyn MacDonald
(Re) Presenting Arguments
• Statements and sentences
• Non-Assertive sentences
• Other kinds of discourse (descriptions, explanations, etc.)
• Premise and conclusion indicators
• Re-presenting and evaluating arguments
• Principle of charity and supplying missing premises
• Assessing arguments: logical strength and soundness.
Logic is concerned with the study of the rules of reasoning and arguing.
We need to be able to talk about the parts of an arguments and how different
parts of arguments connect to other parts of the argument.
What is an argument?
A connected series of statements designed or intended to establish another
statement, some of which are called premises designed to establish a conclusion.
Because, since, therefore, etc. are all indicator words. These words are
just a way of indicating that a premise or reason is to follow.
Ex) Mr. Smith’s fingerprints were found on the weapon that killed Mr. Jones.
Furthermore, no more fingerprints were found on the weapon. Therefore, Mr.
Smith killed Mr. Jones.
Logically strong argument: Where the premises support the conclusion with
an agreeable probability.
Sound argument: Is a logically strong argument where the premises are true
and the premises give conclusive evidence for the conclusion.
Valid argument: Doesn’t talk about the truth of the premises, it simply requires
the conclusion to follow the premises IF the premises are true.
You can have a true conclusion following from false premises, but it does
not create a sound argument.
Parts of the argument
Statement: Describes general information. It is an attempt to say something
that is either true or false. If it is a non-sense statement, it is neither
true nor false; it isn’t a statement at all.
Questions are not statements.
Statements are not questions, suppositions, commands, requests or proposals.