Logic
Deduction - type of logic
if the premises are true the conclusion must be true
Modos Ponnes
If A happenied, then B
Therefore A
Logical symbol for therefore “:”
If you touch my stuff again, I’ll punch you
You touched my stuff, so I punched you
Modus Tollens
If A, B
No B and No A
If you touched my stuff again, I’ll punch you
I didn’t punch you because you didn’t touch my stuff
Hypothetical Syllogism (Chain Arguments)
Syllogism - 3 step argument proof
If A, B
If B, C
Therefore A, C
If you touch my stuff, i’ll punch you
If i punch you, it’ll hurt
Therefore If you touch my stuff, it’ll hurt
If you jump in front of a car, you’ll die
Therefore you died because you jumped in front of a car
If you jump in front of a car, you’ll die
You didn’t die because you didn’t jump in front of a car
If you jump in front of a car, you’ll die
If you die, your family will be sad
Therefore if you jump in front of a car, your family will be sad
Categorical Propositions
A - Universal Affirmative
All S are P
E - Universal Negative
No S are P
I - Particular (Not all of the groups) Affirmative
Some S are P
O - Particular (Not all of the groups) Negative
Some S are not P
AEIO Form Moods
All humans are mortal - A
Jeevan is a human - I
:. Jeevan is mortal - I
[:.] = Therefore
This mood is AII
Green means the statement needs 2 terms stated in both lines.
The red is the two terms that are needed in the last line stated.
All humans come from their mother
All Blind people are humans.
:. Blind people come from their mother
All tabbies are cats
All Tabbies have stripes
:. Some cats have stripes
All whales are warm blooded
No gold fish is warm blooded
No goldfish is a whale
All paper comes from plants
No paper is a tree
Some plants are not trees
All humans are people
Some people are dead
:. Some humans are dead
All cancer is a sickness
Some people don’t have a sickness
Some people don’t have cancer
No elephant is red
All cardinals are red
No elephant is a cardinal
No duck is a turkey
All turkeys are birds
Some birds are not ducks
No snake is a mammal
Some animals are mammals
Some animals are not snakes
Some People are NBA Players
All NBA Players play basketball
Some people play basketball
Some humans don’t like pasta
All women are humans
Some women don’t like pasta