Logic 2 Flashcards
It is a definition that is constructed by what
makes it like others (definition by genus
-generic) & what makes it different from
the others (definition by specific
difference)
Example:
● Bird → A vertebrate (genus) with feathers
and the ability to lay eggs (specific
difference).
● Chair → A piece of furniture (genus)
designed for sitting, typically with four legs
and a backrest (specific difference).
Essential
- Gives more notable characteristics of a
thing.
(The subdivisions of a non-essential definition):
A. Distinctive definition - (definition by property) gives the
natural characteristics of a thing that
follows necessarily from the essence
of the thing.
Example:
● Man is capable of distinguishing right from
wrong.
Non-essential.
- provides the mode of the origin of a
thing. It describes how something
is produced
Example:
● Ice → Water that has been cooled
to 0°C or below, causing it to
solidify.
● Cloud → A mass of water droplets
or ice crystals that forms in the
atmosphere when moist air cools
and condenses.
Genetic Definition
- is the definition that states the
cause instead of specific
difference. It describes a thing by
its efficient and final cause.
Casual Definition
- It should not use the defined term as
part of its definition.
Examples:
● An inventor is one who invents
something.
● A wall clock is a clock on the wall.
Definition should not be circular.
RULES OF A GOOD DEFINITION
1.) A definition should avoid vagueness and
ambiguity.
2.) Definition should not be circular
3.) Definition should not be needlessly negative.
4.) 4. Definition must be precise
● Explains a thing by giving characteristics that
are contingently connected with it.
Example:
The colour of the human eye is an accident, for it
belongs in no way to the essence of humanity
ACCIDENTAL DEFINITION
- Opposition is not an adequate way of
defining terms. - A definition must state what a thing is,
not what a thing is not.
Examples:
● Odd is not even.
Definition should not be needlessly negative.
- must not be too narrow or too broad.
a. Definitions that are too broad - it allows us to apply a term to things to
which it cannot be applied
b. Definitions that are too narrow
★ Too specific that it doesn’t apply to all
Example:
● A Woman is a married other (not
applied to females that are not
married)
Definition must be precise
also known as
syllogistic logic, was developed by
the Greek philosopher Aristotle (384–
322 BCE). It is considered the earliest
systematic study of formal logic and
forms the foundation for Western
logical thought.
Aristotelian logic
the first formal system of
reasoning that analyzed how conclusions follow
logically from premises.
Aristotle’s logic
a structured argument consisting of two premises
and a conclusion.
Example:
Premise 1: All humans are mortal.
Premise 2: Socrates is a human.
Conclusion: Therefore, Socrates is mortal.
syllogism
