Ti doesn't actually do anything, though. If the idea is only in your head, it might give you some sort of intellectual hard-on, but it's worthless to everyone else.
I'd ask you to prove it (because I know you can't), but you'd just pollute this thread with pages of pedantic BS.
1)Logic is the language of objective reasoning (doubt this needs further argument)
2)Introverted functions inhere in the unconscious psyche to a greater extent than Extroverted, therefore Ti is in closest affinity with logic.
3)Only through careful calculation could complex systems be designed. As there are two ways to know things, by chance, and through careful systematic inquiry. As a matter of truism, the latter is more reliable than the former.
4)Technically all of philosophy, science and the mathematics are predominantly work of Ti for this reason.
5)Only Extroverted functions directly interact with the external world, however, their actions are necessarily the manifestations of the internal mindset. For example, the reason why you have a computer in front of you is because a certain Ti dom, by the name of George Boole has outlined the axioms of symbolic logic. The advanced version of such a system has soon been applied to our invention of technology. In summary, people who deal with the work of Ti may not be interested in the practical applications of their ideas, however men of affairs very much are. How far our intellectual development has been advanced in the last few milleniums is indicative of this. Especially recently, concerning the advancement of technology. The ideas that have been applied in that enterprise are most relevant to the work of Ti as their foundation rests upon theoretical work in logic.
6)'Validity' of the 'concept' of Introverted Thinking rests upon the truism of the unconscious human tendency towards impersonal judgment which Jung has regarded as 'Thinking'.
By the way Jack, you are a very intelligent man, I am absolutely in awe. Please enlighten me more with your posts, I learn from you every day and I cannot quite describe how much I feel priveleged to have your gracious presence bestowed upon me!
Lateralus, you are a real winner, keep it up too. I am revere your stupendous genius and uncanny ability to express your thoughts in a lucid fashion.