He never said that the conclusion followed from the premise

From

http://thesaurus.com/browse/therefore

Main Entry: therefore

Part of Speech: adverb

Definition: as a result; for that reason

Synonyms:

accordingly,
and so,
consequently,
ergo,
for,
for this reason,
forasmuch as,
hence,
in consequence,
in that event,
inasmuch as,
on account of,
on the grounds,
since,
so,
then,
thence,
therefrom,
thereupon,
thus,
to that end,
whence,
wherefore

--- application. The Etymology online has "therefore" (OE thaerfor as a collateral form of 'for'. Right. Better than having it as a collateral of 'there' right?

Grice's example:

Jack is an Englishman; he is, therefore, brave.

accordingly,

Jack is an Englishman; accordingly, he is brave.


--- Note the parenthetical status. It can go anywhere:
"Therefore he is brave"
"He is therefore brave"
"He, therefore, is brave"
and "He is brave, therefore"


---

and so,

Jack is an Englisman and so he is brave.


consequently,

Jack is an Englishman; consequently, he is brave.

ergo,

Jack is an Englishman; ergo, he is brave.

for,

Jack is brave for he is an Englishman.

for this reason,

Jack is an Englishman; for this reason, he is brave.

forasmuch as,

Jack is brave forasmuch as he is an Englishman.

hence,

Jack is an Englishman; hence, brave.

in consequence,

Jack is an Englishman; in consequence, brave.

in that event,

Jack is an Englishman; in that event: brave.

inasmuch as,

Jack is brave inasmuch as he is an Englishman.

on account of,

Jack is brave on account of he being an Englishman.

on the grounds,

Jack is brave on the grounds of he being an Englishman.

since,

Since Jack is an Englishman he is brave.

so,

Jack is an Englishman; so, he is brave.

then,

Jack is an Englishman; then, he is brave.

thence,

Jack is an Englishman; thence, brave.

therefrom,

Jack is an Englishman; therefrom, he is brave.

thereupon,

Jack is an Englisman; he, thereupon, is brave.

thus,

Jack is an Englishman, thus brave.

to that end,

Jack in as Englishman. To that end: he is brave.

whence,

Jack is an Englishman; whence: brave.

wherefore

Jack is an Englishman, wherefore: brave.