Okay, this is one of those awkward sentences in English. We see the future perfect in the apodosis (then-part of an if-then statement) and the present perfect in the protasis (if-part of an if-then statement). In an earlier explanation of grammar, I would have argued that the present perfect in the protasis is the present perfect subjunctive as I posit below in my two comparative examples, but that doesn't work so much in Modern English because we rarely use the present perfect subjunctive construction in subordinate clauses anymore, which is clearly evinced in the third-person singular inflection (i.e., "if he haven't given"):
"I will have failed if I haven’t given you the confidence
and desire to explore further ..." ("I haven't given" is present
"I would have failed if I hadn't given you the confidence
and desire to explore further..." ("I hadn't given" is the past
In fact, the present perfect subjunctive is very rare these days in English, but it can still be seen in the mandative and hortatory forms, as well as some other forms:
I would rather it have been shorter. (although one could use the past perfect subjunctive here as well and it would mean the exact same thing: "I would rather it had been shorter.")
It's important that he have passed his driving test before he is permitted to drive alone.
It's possible for him to have been there. (the infinitival phrase here forecloses the present perfect subjunctive)
It's possible that he might have been there. ("may" and "might" are often used to foreclose the present perfect subjunctive)
Should he have survived that fall, he will find a way to get in touch with us in some way, shape, or form. ("Should" is used here to
replace the present perfect subjunctive.)
I think this is what you're asking about—why is the apodosis in the future perfect when the protasis is in the present perfect? My answer is that what once followed the "if" here was the subjunctive, but it's not necessarily the case anymore as English has continued to syncretize over the centuries. In Shakespeare's time, this would have been easier to see, although even then the present perfect subjunctive was very rare, which is strange because the past perfect subjunctive has never been rare in English:
If I hadn't failed the exam, I would have passed the class. (past
In essence, the statement that you have written above is basically stating that, at some unknown or unspecific or unimportant time in the future, I have failed at some specific goal on the condition that I have not yet been able to give you the confidence and desire to explore. I believe it's a strange construction because it uses the future perfect in the apodosis rather than the future simple, which is also why it uses the present perfect (subjunctive) in the protasis. It's just talking about a situation that has not yet occurred, but will occur at an unknown or unimportant time in the future. I think it would be easier just to say:
"I will fail if I should / do not give you the confidence
and desire to explore further..." (using "should" here is an attempt to preserve the present subjunctive in English without writing the archaic form "if I not give" or "if I give not"; "do" is being used as the periphrastic present simple indicative after "if", which is vastly more common in Modern English.)
In my mind, this is simpler, but it's more direct than your example using the future perfect in the apodosis.
I hope this might have helped you out. If you should have any more questions, please feel free to ask, especially if my explanation should be confusing you.
Take care and good luck!
P.S. Sergey, you have asked why the future real conditional takes the future simple in the apodosis and the present simple in the protasis. There is a reason for it. In the English of yore (times long ago), the protasis did not take the simple present indicative; it took the simple present subjunctive form, which is one of the reasons why it seems so weird to you:
"But if the courses be departed from, the ends will change. Say it
is thus with what you show me." Ebenezer Scrooge, A Christmas Carol by
Charles Dickens, 19 December 1843. (notice "if [they] be departed
from; not "if they are departed from")
If he fail this exam, he will not pass this class. ("if he
fail"; not "if he fails")
Over time, this form started to die off because English is syncretic, which basically means it doesn't have many inflections. For instance, in the simple present indicative, the only inflectional change is in third-person singular, i.e., "he goes". The rest of the paradigm of the verb "to go" uses "go" as its inflectional form: "I go, you go, we go, you go, they go". Do you comprehend this? However, in the simple present subjunctive, the inflectional forms are all stale: "I go, you go, he go, we go, you go, they go". Over time, the subjunctive in clauses with subordinating conjunctions such as "if" transformed into the simple present indicative in an effort to rid English of the subjunctive:
But if the courses are departed from, the ends will change. Say it
is thus with what you show me. (notice "are" now; not "be")
If he fails this exam, he will not pass this class. (notice
"fails" now; not "fail")
But some people like me still truckle to the present subjunctive, but it can be awkward saying it with subordinating conjunctions such as "if" in Modern English because people will often look at you as though you were speaking Shakespearean English (really old English); therefore, there is a middle ground in which one can use "should" as well as some other modals in English in some rare instances:
But if the courses should be departed from, the ends will change.
Say it is thus with what you show me.
If he should fail this exam, he will not pass this class.
When we use "should" to replace a present subjunctive in an if-then clause (or a present perfect subjunctive of some form), we can invert it, thereby removing the "if":
But should the courses be departed from, the ends will change.
Say it is thus with what you show me.
Should he fail this exam, he will not pass this class.
The present subjunctive is still common, though, in certain "that" clauses, which usually form the mandative subjunctive:
I demand that she go with you. (not "she goes")
I recommend that he pay now instead of later. (not "he pays")
The "that", however, is not mandatory in these clauses:
I recommend he pay now instead of later. ("that" is optional)
The present subjunctive in Modern English is usually negated without a periphrastic "do / does" and with the "not" between the subject and the present subjunctive verb:
It is important that they not speak too rapidly during their
presentation. (not "they do not speak")
I suggest that you not do anything to upset them. (not "you do
I recommend that he not buy this product. (not "he does not buy")
The simple past subjunctive can only be noticed in the verb "to be", and only in the first-person singular and third-person singular forms:
If I were in charge, I would fire you. (not "I was")
If it were up to me, you would still be in jail. (not "it was")
But the simple past subjunctive of "to be" looks equivalent to the simple past indicative of "to be" for the remaining persons:
If you were in charge, I would quit.
If they were here, we could finish this assignment.
For the remaining verbs in Modern English, the simple past subjunctive forms look equivalent to their simple past indicative forms:
If she owned this company, it would be bankrupt in six months.
If he spoke better English, there would be no problem here.
If we had more money, we could go out for dinner tonight.
Please read more about the subjunctive at my link here: Could 'it' be regarded as plural? Why is 'were' used instead of 'is' in "...if it were cleaned and fed..."?.
If you should have any more questions, please feel free to ask and I shall try to respond as quickly as possible as long as it not be too late in the evening (present subjunctive forms rather than "you have" and "it is not", which are present indicative forms, although "you have" is also the present subjunctive form as well).