I've been following this thread with great interest, and appreciate the discussion between you and Jim.
One quick question: are you saying that a US provisional which lacks an enabling disclosure for an invention ultimately claimed provides a benefit to an applicant for EPO purposes?
In one word: no.
Mr. Ivey is correct that a US provisional application that fails to meet the requirements of 37CFR§53(c) is not a priority document according to US law.
What I have been trying to point out (unsuccessfully I suppose) is that there is a difference between what qualifies as a priority document under 37 CFR § 53(c), what it needed to satisfy the patent statute, and what would be considered a well-written application for patent.
In sofar as sufficiency of disclosure, if you do not meet the basic, minimum requirements of 35 USC § 112 paragraph 1 then you can't file a provisional application. Period.
But as any patent attorney/agent knows there are logarithmic differences between meeting the sufficiency of disclosure requirements of 35 USC§112, what is required to satisfy all the requirements of the US patent statute, and what would be considered a well-written, regular application for patent.
Considering that EPO requirements for enablement are generally somewhat lower than in the US, and there is no requirement to disclose the "best mode" a provisional application that met US requirements would almost certainly satisfy EPO requirements.
So what happens at the EPO if at a later stage if the US application (which may meet EPO requirements) is rejected by the USPTO based on insufficiency of disclosure in the provisional application according to tougher US standards? Well, your guess is as good as mine. I am not aware of any case where this has been tested. As I said, the US provisional application is a big black hole waiting to be filled with judicial interpretation.
Where I entered this thread was to refute the black and white statement that US provisional applications are always a waste of time and money. This is simply untrue.
In addition to their intended purpose of allowing foreign applicants to establish an earlier date of priority "in this country" (which is vital to become prior art to other pending US applications) there are also other instances - such as those I have described in this thread - where it may make sense.
Moreover, in certain situations, going the "provisional" route can serve important strategic and tactical purposes, but this is something I will share in another thread.
I am by no means suggesting that you can get something for nothing, but it is certain that if you fail to secure a priority date before disclosing your invention to the public, then nothing is what you will be able to get in most other countries of the world.