"Let him first answer our Therefores, and wee will quickly answer his Wherefores"

He being Grice.

From

http://painintheenglish.com/?p=1520

"It is acceptable to use a comma for short clauses (Chicago Manual of Style):

I ate a burger, I'm full.

"But that looks hideous on the page."

--- this belong is quoted
-- begin quoted text:

Commonly,

-Because… (therefore implied):

Because I ate a hamburger, I'm full. (very clear)

-That… (to be ("is") attribute):

That I ate a hamburger, I'm quite full.

(kinda prosaic)

-If… then:

If I ate a hamburger, then I'd be full.

(more formal)

-If… (then implied):

If I ate a hamburger, I'd be full.

(less formal but flows better in speech)

-Since… :

Since I ate a hamburger, I've been full.

(time: I've been full since then.)

-Since… (then implied):

Since I ate a hamburger, I'm full.

(logic: "since" used as an alternative to "because")

-As… :

As I ate a hamburger, I got full.

(time and logic)

-As… :

As I'm hungry, I think I'll go eat a hamburger.

(alternative to "because" and "since")

and many more, included inverted logic and time.

"Thus" is rarer (no pun intended) and tends to be used as a conclusion after a lengthy train of thought and is used to mean "in the manner indicated," most often found in instructions and is therefore less appropriate for logical expression:

Today, I ate so many things. I ate…. Therefore, I'm full.

This is how you could prepare a hamburger. First, put the beef on the grill… Thusly, you now have a feast.

Or,

Thus, it's easy to see how you could prepare a feast for cheap.

--- end of quoted text.

Application to Grice's example:


-Because… (therefore implied):

Because I ate a hamburger, I'm full. (very clear)

Because he is an Englishman, Jack is brave.

-That… (to be ("is") attribute):

That I ate a hamburger, I'm quite full.

That Jack is an Englishman, Jack is brave.

(kinda prosaic)

-If… then:

If I ate a hamburger, then I'd be full.

If Jack is an Englishman, then Jack is brave.

(more formal)

-If… (then implied):

If I ate a hamburger, I'd be full.

If Jack is an Englishman, Jack is brave.

(less formal but flows better in speech)

-Since… :

Since I ate a hamburger, I've been full.

Since Jack is an Englishman, Jack is full.

(time: I've been full since then.)

-Since… (then implied):

Since I ate a hamburger, I'm full.

(logic: "since" used as an alternative to "because")

-As… :

As I ate a hamburger, I got full.

As Jack is an Englishman, Jack is brave.

(time and logic)

-As… :

As I'm hungry, I think I'll go eat a hamburger.

(alternative to "because" and "since")

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Other:

Jack is an Englishman, he is, so, brave.
Jack is an Englishman; so, he is brave.
Jack is an Englishman and so he is brave.


Jack is an Englishman; thus, he is brave.
Jack is an Englishman and thus he is brave.

Because Jack is an Englishman he is brave
Jack is brave because he is an Englishman.

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And other myths! (Talk of the myth of conventional implicature).

If "thus" is pretentious and obsolete, what about 'ergo'? Just kidding.