|(O)|(O)| |
| .---|---. | There is no
| | | Conclusion.
.---------------.

(5)

"All selfish men are unpopular;
All obliging men are popular.
All obliging men are unselfish".

Univ. "men"; m = popular; x = selfish; y = obliging.

.---------------. .-------.
"All x are m'; |(O) | (I)| |(O)|(I)|
All y are m. | .---|---. | |---|---|
All y are x'." | |(O)|(O)| | |(I)| |
|---|---|---|---| .-------.
| |(I)| | |
| .---|---. | .'. "All x are y';
|(O) | | All y are x'."
.---------------.

Hence proposed Conclusion is _incomplete_, the _complete_ one
containing, in addition, "All selfish men are disobliging".

(6)

"No one, who means to go by the train and cannot get a
conveyance, and has not enough time to walk to the
station, can do without running;

This party of tourists mean to go by the train and cannot
get a conveyance, but they have plenty of time to walk
to the station.

This party of tourists need not run."

Univ. "persons meaning to go by the train, and unable to get a
conveyance"; m = having enough time to walk to the station; x = needing
to run; y = these tourists.
pg069
.---------------.
"No m' are x'; |(O) | |
All y are m. | .---|---. |
All y are x'." | | | | |
|---|(I)|---|---|
| | | | |
| .---|---. | There is no
|(O) | (O)| Conclusion.
.---------------.

[Here is _another_ opportunity, gentle Reader, for playing a
trick on your innocent friend. Put the proposed Syllogism before
him, and ask him what he thinks of the Conclusion.

He will reply "Why, it's perfectly correct, of course! And if
your precious Logic-book tells you it _isn't_, don't believe it!
You don't mean to tell me those tourists _need_ to run? If _I_
were one of them, and knew the _Premisses_ to be true, I should
be _quite_ clear that I _needn't_ run--and I _should