Types of Definitions
definition
Logic
Essential means necessary or important
Defining by synonym
The sun is often visible at night
False by definition
When two statements can be true at the same time
Consistent statement
When a definition has more than one possible meaning
Ambiguous definition
Any statement is either true or false
Law of Excluded Middle
When a mom gives a child a penny after the child asks what money is.
Defining by example
You either know the answer or you do not
Tautology
The truth of the first requires or necessitates the truth of the second
When terms relate to other terms
Relationships
A statement cannot be both true and false
Law of Non-contradiction
A triangle is a three-sided polygon
Defining by genus and difference
I believe in God the Father, maker of heaven and earth
Self- report
The first statement must imply the second statement and the second statement must imply the first
Logically equivalent
"By small I mean five dollars."
Precising Definition
If a statement is true then it is true
Law of Identity
Japan, Israel, Egypt - Nations
Defining by Example
The breeze is a gentle wind
True by definition
The truth or falsity of one has no effect on the truth or falsity of the other
Independent statements
A new word is invented or an existing word is applied in a new way
The two main branches of logic
Formal and Informal
Whisker - short facial hair
Defining by genus and difference
The printing on this page is black
Supported by experience
Logic is hard. Spanish is hard.