You haven't felt like your intelligence was being undermined? I don't know, it just seems so clear to me at the times I've felt this way. And there are a lot of situations which might trigger it, so I can't really say what constitutes it, because there are many ways it could manifest. But that's interesting that it's not an issue for you. Maybe I have less faith in my knowledge than you do, and so I seek external validation?
Perhaps. No amount of telling me I'm wrong or even insulting me will make me question my intelligence. Generally, only two things can make me do that: (1) recognizing I have made a serious mistake or error in judgment; and (2) meeting someone who really is much more intelligent than I am.
The lack of explanation is really lack of clarification. That's a better way to put it. If someone doesn't understand what you're talking about when you tell them they're wrong, it's only proper to explain why. I can understand, if you have some grand Ni theory which you have just divulged and a Ti person comes along and says it's rubbish why you'd feel an Fi reaction to just say you believe it and that's that- but it's not usually done out of hostility, it's just wanting to learn. See, this would be an example I think the other way around, which would be an XNTJ feeling their intelligence is being undermined.
If someone doesn't understand my Ni theories, my natural reaction is to question their intelligence, not my own. I don't act on this, however, because I have learned that the fault often does lie with me, not with my intelligence but with my explanation. Unless they are being a jerk about it, I will make the effort to clarify to their satisfaction.
Live with one, have worked with two, have dated three, and have one as a sibling. I know my way around the INTJ circuit, including the knee-jerk Fi reaction on display here anytime you try telling them that one of their systemic inabilities is (gasp!) anything less than just another sign of their superiority and awesomeness in every tangible and intangible field of everything. Maybe INTJs can squeak out a few practical tasks when they absolutely have to, but nowhere near as good as SPs...and in my experience dealing with them, they much prefer to delegate such tasks as much as possible. The bulk of the 'work' they do involves endless research into a project, and finding people to help them with it. Attempting to dive in themselves and complete something in a timely fashion typically results in unexpected problems along the way, which infuriates them, and more often than not causes them to give up on the task completely (until they can find someone to do it for them), or just get it to a half-ass 'workable' level of completion. INTJs have remarkable patience in areas of no resistance, but in the presence of a sabotaging reality they just can't deal with it, and shut down-- forever avoiding such tasks in the future, which stunts their ability to problem solve mechanical reality.
There is something to the Fi reaction you describe, and the tendency to see our weaknesses as strengths, or at least as not a problem. The rest, however, is unlike the INTJs in my acquaintance. I would say it sounds more like INTPs, but the INTPs are less likely even to try to implement their ideas. That is why we often make a good team. INTJ exterrnal judging drives us to realize our ideas and plans (or help an INTP realize theirs), not just think about them, and we will go to amazing lengths to make that happen. We teach ourselves whole new skills just to accomplish something, partly because we don't have (or don't think we have) the people skills or trust to delegate and engage a team. An INTJ with the failure rate you describe would be in dire straits indeed. Yes, SPs are the true masters at anything hands on and responding successfully in the moment. NTJ responses are slower, less reflexive, and based on doing our homework. The SP responds in the moment out of instinct; the NTJ responds out of planning and preparation. Another good team.
AA has it right below:
I think quite a lot of INJ's and especially INTJ's like to shore up weaknesses as part of their contingency planning. Usually something involving an improvement in physical prowess, although this is by no means a rule. Although it's worth mentioning that this isn't necessarily anything to do with dealing with inferior influences.
The bolded is my initial assertion as to why my preference coexists with a state of being farrrrrrrrrrrrrrrrrrrrrrr removed from introverted intuition. Human intuition is shown to be laughably weak at determining a true state of affairs, and Ni does not equate to good intuition, it equates to a higher propensity to employ intuition (and worse, stick by its guns).
On average, this is likely correct, but then Ni-doms are a small minority of the population. If practice makes perfect, or at least improvement, types who prefer Ni and use it more will become better at it than others. That tendency to stand by our intuitions comes from a track record of their being correct, especially in certain areas or circumstances. I can almost assign a confidence level to my Ni ideas, and usually come fairly close.
I'm taking your side on this one; it's not that considering the various possibilities intuition can present us with is bad, but what is bad is when we act on it or assume things without question. I used to have a bigger problem with this, although I've found over time with experience that our intuitions are often off, or at least incomplete. The truth quite often actually seems to be counter-intuitive - that is, it goes against our initial expectations.
As [MENTION=8413]Zarathustra[/MENTION] said, you might be wise to doubt your intuition, but not ours. Moreover, I at least never trust it without question. If I don't have the means to answer those questions, though, and it is an area where my intuition has been right on in the past, I will trust it when a decision needs to be made. This is Ni and Te working together, with obvious influences of Fi and Se as well (considering available facts, and understanding the need/value of acting to support a goal).
The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt. -- Bertrand Russell
Combine all this, and you have INTJs in a nutshell.