After reading the sobeit/so be it article, Shirley in Berkeley has this to say:

Sobeit sounds like legal-speak to me. Â Working as a temp for a lawyer, I asked about their dropping the “e” from “therefore” and was told that it was legal usage: “therefor” meant “for that,” and with an “e” on the end, meant “hence.”

**therefor**: adv. for that [thing]; for that, for it

Ex. *I will give you my pocket knife if you will give me your watch therefor.*

**therefore**: adv.consequently, hence

Ex. *I think, therefore I am. I was afraid; therefore I ran.*

Sure enough, lawyers have more use for the form **therefor** than the rest of us.

…respondent will not know how to defend against petitioner’s case because it does not know how petitioner is calculating the charges, and the justifications therefor.

BOND ORDINANCE PROVIDING FOR THE RECONSTRUCTION OF

WATER STREET AND APPROPRIATING $170,000 THEREFOR

As a noun **therefore** can mean a conclusion or inference:

Let him first answer our Therefores, and wee will quickly answer his Wherefores. (example in OED)

There is also a **therefore** symbol:

In a mathematical proof, the therefore sign . . . is a symbol that is sometimes placed before a logical consequence, such as the conclusion of a syllogism. The symbol consists of three dots placed in an upright triangle. In reading, it is pronounced “Therefore,” â€¦. It is Unicode character U+2234 and on some systems may be entered using ALT-8756 (the decimal version of 2234). While it is not generally used in formal writing, it is often used in mathematics and shorthand. —Wikipedia

The therefore symbol brought back memories: used it in the early 80s at varsity when taking lecture notes.

I also remember the “therefore sign”, but from a somewhat earlier era than does Kristan. We used it in constructing geometry proofs in high school (I doubt that anyone goes to such trouble any more). We might have read it as “ergo”, however, rather than “therefore”.

I have more often seen the “therefore” symbol in mathematics and logic written somewhat like a triangle as in:

âˆ´

Though, seeing as I am going through my undergraduate education now, that may be a more modern thing?

Yep. I just used “therefor” in a motion for summary judgment.