Apple
I disagree with this one. In fact I am having trouble coming up with a concise intentional definition at all.
The fruit of various trees of genus Malus;
How does one define a genus? By it's genome? I would call an entirely artificial fruit 'an apple' if it were sufficiently similar to one.
green, yellow, or red in color; possessing a fivefold symmetry readily observable in cross-section;
If we bred them to be blue and to have a fourfold symmetry, they would still be apples.
I've really picked apart this one example but your comment is good overall and I applaud you for taking the time to write all this up; many of my definitions were very complex, so I did not bother.
How does one define a genus? By it's genome? I would call an entirely artificial fruit 'an apple' if it were sufficiently similar to one.
I would call a raven a writing desk if it were sufficiently similar to one :P
But yeah, since we're really talking about human pattern-matching, apple is defined in terms of "common but not strictly necessary traits." Similar violations of any non-fuzzy definition could be constructed for shoes (hand-shoes), wire (a piece of wire shorter than it was wide), green (yellow), politicians (candidates), and hope (s...
Exercise for “Extensions and Intensions”
Give an intensional definition for each of the following words:
Now rank them from easiest to define to hardest.
Describe how you would give an extensional definition of the same words:
Again, rank them from easiest to hardest.
Are the two lists the same? If not, what tends to make something easier to define intensionally than extensionally and vice versa?
You can share your answers in the comments. I'm interested in seeing how similarly people think of these things. Please make suggestions as to how this could be improved or augmented and what to do the same/differently in future exercises. My current plan is to do more from the sequence "A Human's Guide to Words." This post will be edited in response to suggestions.