A lot of people seem to not understand the fundamental nature of introversion and extroversion attitudes as they manifest within the thinking function, and hence this thread to provide a very simple explanation of these two functions that ought to make sense to everyone. If it does not, please reply with any questions you have, or information you wish to provide.
The very essence of introverted functions is that they are based upon values and principles that come from the user, not necessarily from the external environment. I say 'not necessarily' because there can and will be times when someone will arrive at a subjective opinion that can be, and is empirical, and is or can be validated objectively. The primary thing to focus on is the preference of the individual who arrives at a conclusion. Did they arrive at this conclusion based on their own subjective interpretation?
Te is the opposite of this. Te users tend to bounce ideas off other people, and can be extremely expressive, even to the point of appearing to be extroverts in the case of well-developed INTJs. Te seeks and requires external, objective validation, either from other people, or from objective reality itself. For this reason, it tends to distrust conclusions that are arrived at through mere internal validation, and hence INTJs are stereotypically called 'scientists' - they tend to want to validate themselves by experimentation, or by referencing some matter of fact that can be observed and confirmed rationally by anyone who is rational.
People who prefer to use Ti will not always require this. Again, because the validation is subjective, it comes from the user and does not necessarily require something external to validate itself. It can, and often is, sufficient that the idea is internally consistent and therefore internally logical within the world-view/framework for understanding that the Ti user prefers. Ti users do not always appreciate the sort've 'generic' world-view that feels 'imposed' upon their way of thinking, and this is why INTPs are extremely abstract thinkers and great at coming up with truly original ideas. They see the universe in what is often a totally unique way - and this is also their Achilles heel for the exact same reason. Because their view is so personal and subjective, they can find it very hard to relate what they personally know to other people. In many cases, they might decide it is not worth the effort and not even try.
This is why I have observed that INTPs can be a lot more introverted than INTJs. INTJs have Te for an auxilliary function, and again, Te requires something external to validate the reasoning process. It simply must make sense to other rational people, or at least make sense in a way that provides a useful application that can be demonstrated objectively. If it does not, the Te user will have a hard time accepting the idea. It will seem to need refinement, or seems to require some kind of practical purpose to make it meaningful and not simply a good theory. This is where a lot of the friction between Te and Ti users comes from - because Te almost always needs objective validation, and Ti does not always need this. I put emphasis on 'need' and 'always' in the last sentence to illustrate that although Ti is subjective, and Te is objective, once again both functions are at their core, thinking, rational functions, and both will often arrive at the same conclusion for that reason, regardless of whether this conclusion is arrived at subjectively or objectively.
I hope this clears up any confusion that many of you may have about the two functions in comparison, and helps some of you still trying to figure out which one you prefer over the other.
The very essence of introverted functions is that they are based upon values and principles that come from the user, not necessarily from the external environment. I say 'not necessarily' because there can and will be times when someone will arrive at a subjective opinion that can be, and is empirical, and is or can be validated objectively. The primary thing to focus on is the preference of the individual who arrives at a conclusion. Did they arrive at this conclusion based on their own subjective interpretation?
Te is the opposite of this. Te users tend to bounce ideas off other people, and can be extremely expressive, even to the point of appearing to be extroverts in the case of well-developed INTJs. Te seeks and requires external, objective validation, either from other people, or from objective reality itself. For this reason, it tends to distrust conclusions that are arrived at through mere internal validation, and hence INTJs are stereotypically called 'scientists' - they tend to want to validate themselves by experimentation, or by referencing some matter of fact that can be observed and confirmed rationally by anyone who is rational.
People who prefer to use Ti will not always require this. Again, because the validation is subjective, it comes from the user and does not necessarily require something external to validate itself. It can, and often is, sufficient that the idea is internally consistent and therefore internally logical within the world-view/framework for understanding that the Ti user prefers. Ti users do not always appreciate the sort've 'generic' world-view that feels 'imposed' upon their way of thinking, and this is why INTPs are extremely abstract thinkers and great at coming up with truly original ideas. They see the universe in what is often a totally unique way - and this is also their Achilles heel for the exact same reason. Because their view is so personal and subjective, they can find it very hard to relate what they personally know to other people. In many cases, they might decide it is not worth the effort and not even try.
This is why I have observed that INTPs can be a lot more introverted than INTJs. INTJs have Te for an auxilliary function, and again, Te requires something external to validate the reasoning process. It simply must make sense to other rational people, or at least make sense in a way that provides a useful application that can be demonstrated objectively. If it does not, the Te user will have a hard time accepting the idea. It will seem to need refinement, or seems to require some kind of practical purpose to make it meaningful and not simply a good theory. This is where a lot of the friction between Te and Ti users comes from - because Te almost always needs objective validation, and Ti does not always need this. I put emphasis on 'need' and 'always' in the last sentence to illustrate that although Ti is subjective, and Te is objective, once again both functions are at their core, thinking, rational functions, and both will often arrive at the same conclusion for that reason, regardless of whether this conclusion is arrived at subjectively or objectively.
I hope this clears up any confusion that many of you may have about the two functions in comparison, and helps some of you still trying to figure out which one you prefer over the other.