Intensional: Human sensation of the anticipation that a severe negative outcome will be avoided, when the circumstances are outside of one’s control.
Extensional: A student waiting to receive the result of their final exams, for which a passing grade is required to pass the course. A rationalist wishing that cryonics will be successful. A religious person praying to God to cure a family member’s cancer.
N.B. Perhaps it is useful to distinguish between hope and optimism. We may want to call a person who constantly looks at the positive effects of a situation optimistic; it seems more appropriate to use “hope” when the stakes are higher and there is an element of desperation.
Wire
Intensional: Piece of material designed to efficiently carry electrons (low-cost and relatively high sensitivity to changes in electric potential across distances) across its length.
Extensional: CAT-5 cables, power lines, circuit board wiring.
N.B. The efficient criteria implies the thinness and longness of the wire, relative to the wire capacity.
Green
Intensional:
A certain wavelength of light, the intensity of which directly corresponds to the signal strength of the human M-type cone when such light is shone upon it.
The attribute of an object that directly corresponds with the reflectivity of the aforementioned wavelength of light shone upon it.
Extensional:
Output of a green laser, the green spectral line of Mercury, the output of a light filter that only lets green light through.
The reflectivity of green paint, the reflectivity of grass.
Politician
Intensional: Person who is popularly known for having had a significant direct impact on politics (the policy and/or decision-making part of a government or otherwise a large, self-sufficient group of people with shared interests) and has done so for a significant amount of time.
Extensional: Chuck Schumer, Schwarzenegger, Gandhi, Deng Xiaoping
Apple
Intensional: (taken from Wikipedia, since I can’t come up with anything better and I don’t know much about taxonomy) The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family (Rosaceae).
Extensional: McIntosh apple, Granny Smith apple, Red Delicious apple.
N.B. For almost everything, including apples and genera, it is often more useful to think about whether something is more blegg-like than rube-like, than to think about whether an item is a blegg or a rube.
Difficulty of generating intensional definition (easiest to hardest): Shoe, Wire, Hope, Green, Politician, Apple
I found it very easy to generate extensional definitions once the intensional definitions were generated. However, this may have been a side effect—once I came up with examples that fit my intuition, but did not fit the intensional definition, I would revise the intensional definition to include it.
I found it easier to generate definitions when there’s a clearly defined purpose for the entity in question. It’s harder to define things when there are seemingly arbitrary boundaries (in the case of apple and politician).
Exceptions: socks; a girl who hopes to be a doctor when she grows up; barbed wire
Also, the mayor of a town is generally called a politician despite not being well-known outside a narrow circle and possibly being newly elected.
Shoe
Intensional: Article of clothing primarily designed to be worn on the foot.
Extensional: Hiking boots, flip-flops, snowshoes, Vibrams.
Hope
Intensional: Human sensation of the anticipation that a severe negative outcome will be avoided, when the circumstances are outside of one’s control.
Extensional: A student waiting to receive the result of their final exams, for which a passing grade is required to pass the course. A rationalist wishing that cryonics will be successful. A religious person praying to God to cure a family member’s cancer.
N.B. Perhaps it is useful to distinguish between hope and optimism. We may want to call a person who constantly looks at the positive effects of a situation optimistic; it seems more appropriate to use “hope” when the stakes are higher and there is an element of desperation.
Wire
Intensional: Piece of material designed to efficiently carry electrons (low-cost and relatively high sensitivity to changes in electric potential across distances) across its length.
Extensional: CAT-5 cables, power lines, circuit board wiring.
N.B. The efficient criteria implies the thinness and longness of the wire, relative to the wire capacity.
Green
Intensional:
A certain wavelength of light, the intensity of which directly corresponds to the signal strength of the human M-type cone when such light is shone upon it.
The attribute of an object that directly corresponds with the reflectivity of the aforementioned wavelength of light shone upon it.
Extensional:
Output of a green laser, the green spectral line of Mercury, the output of a light filter that only lets green light through.
The reflectivity of green paint, the reflectivity of grass.
Politician
Intensional: Person who is popularly known for having had a significant direct impact on politics (the policy and/or decision-making part of a government or otherwise a large, self-sufficient group of people with shared interests) and has done so for a significant amount of time.
Extensional: Chuck Schumer, Schwarzenegger, Gandhi, Deng Xiaoping
Apple
Intensional: (taken from Wikipedia, since I can’t come up with anything better and I don’t know much about taxonomy) The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family (Rosaceae).
Extensional: McIntosh apple, Granny Smith apple, Red Delicious apple.
N.B. For almost everything, including apples and genera, it is often more useful to think about whether something is more blegg-like than rube-like, than to think about whether an item is a blegg or a rube.
Difficulty of generating intensional definition (easiest to hardest): Shoe, Wire, Hope, Green, Politician, Apple
I found it very easy to generate extensional definitions once the intensional definitions were generated. However, this may have been a side effect—once I came up with examples that fit my intuition, but did not fit the intensional definition, I would revise the intensional definition to include it.
I found it easier to generate definitions when there’s a clearly defined purpose for the entity in question. It’s harder to define things when there are seemingly arbitrary boundaries (in the case of apple and politician).
Exceptions: socks; a girl who hopes to be a doctor when she grows up; barbed wire Also, the mayor of a town is generally called a politician despite not being well-known outside a narrow circle and possibly being newly elected.