Mondays: always lectures (mostly)
Tuesdays: exercise lessons (mostly)
Check schedule regularly basically. Rooms may vary depending on week.
No recorded classes.
Keep track of Toledo.
Teacher won’t check messageboard lål. (Other students might help you on the messageboard though)
Email is fine though.
Textbook: An introduction to Formal Logic 2nd edition by Peter Smith. (around 400 pages)
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available online
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Toledo, and https://www.logicmatters.net/ifl/
Exams:
in January, closed book, written exam, theoretical questions & exercises (50/50)
Mock exam:
Early December, very representative of difficulty level, grades don’t count towards final grade, however not all topics are present (Natural deduction). Natural deduction can be replaced by Tableaux.
”How to get full marks” specifically will be discussed in class.
First we do informal logic
Then we do PL (propositional logic)
3-4 chapters on QL (quantitative logic) (math???)
and lastly modal logic from another book usually.
Last year… were about 124 students registered for the course, about 103 did the exam
58/103 = 56.3% passed
66 people could resit the exam later: 37 participated: additional 16 passed the course
In the end between 53-60% cleared the course
Average grade: 10.6
The business of logic is the sytematic evalutation of arguments for their internal cogency:
- cogency can be: narrative, visual or, as in logic, based on validity.
Ie. Validity is a kind of cogency
The job of logic is to assess arguments for their ”validity”.
What is an argument?
Roughly: utsaga wherein a conclusion and various reasons are given.
It is useful for finding out which parts an argument are valid or only rhetorical.
Eg: all logicians are smart, Lorenz is a logician → Lorenz is smart.
(”Modus ponens on steroids.” lål)
(Normal modus ponens works on if-then basis)
premises (0, 1, 2 or more pieces that build up the argument, it can be very flexible.)
conclusion (exactly 1 per argument)
example of an argument that is valid despite 0 premises: ”Therefore Lorenz is or is not smart”
Natural language is usually self-referential, formalised logic cannot. (Due to liar’s paradox and such)
The conclusion doesn’t have to be at the end; the premises don’t have to be a the beginning:
look for markers in natural language/formal logic.
eg. Lorenz is smart, since all logicians are smart, and lorenz is a logician.
We need to keep track of INFERENCE MARKERS
so, therefore, consequently… indicate conclusion
since, because, after all.. indicate a premise
Reasoning = giving reasons
Watch out for terminological confusion
words like, to argue, ”an argument” are ambiguous.
Here it means to give reasons for a conclusion.
Reasons are everywhere!
One explanation as to why we reason is because we want our beliefs to be true; goal in itself + to act better
if you have reasons for your beliefs, it seems that they are more likely to be true, at least they are well formalised and are easier to understand.
”All humans are mammals, Lorenz is a mammal, so Lorenz is a mammal.”
You can evaluate this from at least 2 points of view:
Truth-Falsity of the argument;
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is the first premise true or false?
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is the second premise true or false?
-is the conclusion true or false?
We are currently analysing individual parts of the argument, this is not how we work in logic.
ie. In logic this is not an interesting diametric.
Validity- Invalidity of the argument;
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Does the conclusion really follow from the premises, or not?
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Can we proceed from the premises to the conclusion?
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property of an inference or the argument as a whole
These are the sort of questions that are relevant in analysing something logically.
It is important not to commit categorical mistakes like this.
Validity seems to be defined using truth, however, there is still a semi-independent relation between truth and validity.
Validity:
If we assume that all premises of the argument are true, then we have to agree that the conclusion is true as well.
Or;
There is no way in which all premises can be true, while the conclusion is false.
Validity and rationality:
- Suppose that someone agrees with all the premises, but denies the conclusion; we call them irrational
→ This person contradicts himself, → irrational
Logical operators:
All
No
Or
If-Then