B.Contraposition Test
If Taub (still) plans/is to negotiate with Schneider, he (still) needs to go to New Hamburg.
=> If Taub does need to go to New Hamburg (anymore), he does not plan/is not to negotiate with Schneider (anymore).

(8)Failure of the Hypothetical Syllogism (Transitivity)
If Hoover had been a Communist, he would have been a traitor.
If Hoover had been born in Russia, he would have been a Communist.
~=> If Hoover had been born in Russia, he would have been a traitor.

(9)Failure of Contraposition
(Even) if Goethe hadn’t died in 1832, he would still be dead now.
~=>If Goethe were alive now, he would have died in 1832.

Ok, now let us see some sentences like the ones discussed above and apply the tests:

A.Hypothetical Syllogism Test
If you intend to get to Paris today, you must take the A train now.
If you want to attend Sartre’s lecture in time, you intend to get to Paris today.
=> If you want to attend Sartre’s lecture in time, you must take the A train now.

In the scenario where it is known that two businessmen can only negotiate if they meet in the southern Brazilian city of New Hamburg, the pair below is intuitively ok to me:

B.Contraposition Test
If Taub plans/is to negotiate with Schneider, he needs to go to New Hamburg.
=> If Taub needs to go to New Hamburg, he plans/is to negotiate with Schneider.

Thenceforth, in the examples examined above the anankastic conditionals do not behave as counterfactuals.
If anyone thinks I am wrong, please correct me.

{A} Firstly, I want to understand why (I) below would be a counterfactual in a natural language?

(1) To survive you need to drink water and breathe air.

For me a counterfactual sentence related to (1) would be something like (2):

(2) If you did not need to drink water and breathe air, then you would survive even on the Moon.

But if the necessity of taking a certain train is a fact, inasmuch as the need of air and water, why would it be something contrary to the fact?

For me, what seems to be case is that first there is a presupposition-filtering mechanism at work. But this is not something limited to counterfactuals in human languages.

Perhaps it is just my ignorance on the subject, in which case I be your pardon.

{B} Secondly, the frequent use of paraphrases can in some cases be misleading in the study of human languages. And word or constituent order is a very important factor to be taken into consideration. Human languages are not commutative. Thus, I am not sure whether in all languages a sentence like

You have to take the A train (to go to Harlem) if you want to go to Harlem.

is really perfectly equivalent to:

If you want to go to Harlem, you have to take the A train (to go to Harlem).

I can think of pair of (counter-)examples in English:

(3) a. If you undertand me, you have to follow the book.
b. You have to follow the book, if you undertand me.

The semantic and pragmatic differences between a and b above clearly depend on the order of the clauses.

For the syntax-semantics interface there are problems too. If one considers binding relations, then it is clear that the paraphrasing will not produce perfect equivalents:

(4) a. He[1] has to take the A train, if Daniel*[1]/[2] want to go to Harlem.
b. If Daniel[1] wanst to go to Harlem, he[1]/?[2] has to take the A train.

Maybe it is just my little grasp of what Stechow and ali mean, but I would like to see some answers to these questions.