Hmm, looks like Adymus, et all got here faster than I did. My argument is basically the same, but through a slightly different lens. (Humans all see life through slightly different lenses anyway, depending on how their brain is wired to be a certain type, as well as environmental factors and life experience, etc.) This argument is therefore a series of metaphors and hypothetical situations; everything ties together in the end.
It seems you are considering the possibility of type being malleable and the possibility that type is unchanging as both being equally likely. (This equal weighing of conflicting viewpoints seems to be a disturbing theme in modern Western culture. Given the evidence, is creationism as potentially equally valid as evolutionary biology? Homeopathy with modern medicine?) But I digress. The truth of any matter is out there, no matter if we humans have the tools to discern that yet. Therefore, only one of these answers is correct, and you must try and find falsifiable evidence. Adymus made a lot of good points which contain falsifiable evidence in favor of the claim that type is unchangeable up there, so I will not repeat them.
Another thing to consider is that life is an intricate web of connected systems. There are so many processes that our bodies run without conscious thought, for instance. Your continued survival rests on the power of these bodily systems to do their job. Systems like the respiratory system, the nervous system, the circulatory system, and the reproductive system work so well that is an aberration whenever they are not working properly. Expanding our perspective, humans are also connected to each other in families, tribes, and nations. And these are also interconnected. Consider a family that has been shattered by incestuous rape. The victim's emotional well-being sends signals to the people around her. Perhaps she goes into Child Protection Services. Now taxpayer dollars are being used to protect her and place her with another family. The well-being of the people involved in this small-scale tragedy effects the well being of society as a whole, like a drop of water ripples throughout a puddle. New advances in technology change how people live and how they expect to live. Fancy a life without interior plumbing? The energy infrastructure of every modern country is fundamentally built upon fossil fuel use, and this is why changes in green energy have happened a lot more slowly than environmentalists would hope.
This all basically boils down to the cheesy slogan that no one is an island. You are profoundly influenced by the general culture around you and the systems it currently uses to survive and proliferate. No one but a solipsist with hir head stuck in the ground can deny this; the evidence is all around you. These are but a fraction of a fraction of the examples I could have used.
"What does this have to do with typology?", you might ask. With this perspective, psychology is linked to many other disciplines and humanity and the cosmos at large. So what is true in psychology will be true elsewhere. It'll be as ubiquitous as the
Golden Ratio, which shows up throughout the Earth and the Universe. All researchers are dedicated to taking one step further than what humans currently know. (Or they should look for work elsewhere.) Some scientists, for example, will try to recreate a previously conducted experiment, to see if the conclusions are rock-solid. While it looks like these researchers are just doing boring grunge work, it is necessary to have incontestable proof for a certain phenomena. Newton's ideas used to be the cutting edge in physics, but "cutting edge" ideas are not always true. Generations of physicists solidified his ideas so that Einstein could add on to them. And most importantly in light of this argument, they found that his laws permeated the universe. Human beings have adapted to an environment with the gravitational constant of the Earth, after all.
So taking the interconnection of all things into account, consider the fact that there are potentially infinite life experiences. Everything in life is clamoring for your attention. For instance, in the church I grew up in, the preacher would assert that God and Christianity should be the most important thing, bar none, in the churchgoer's life. He would quote scripture to back up this assertion, whether it was directly said or ever so slightly hinted at. Now most stimuli, activities, etc in life aren't as forward as your average preacher, but the same dynamic is going on.
Time for a thought experiment. Consider the plight of two college students. Let's make them identical twins. They both have the same great potential for excelling in their psychology major. The admissions office at the university is very pleased with the selection of these twins. They both go to the same school, which is renowned for its party scene.
To them, both partying and studying have an appeal to them. Consuming alcohol and perhaps some mild recreational drugs is pretty appealing. A partier ends up having wild, crazy stories and ever wilder sex. He gets to meet people from many walks of life without the pretentious sheen of the persona a person projects when sober. Getting to know people when you are drunk - now that's when you'll see the person's true nature.
Studying, while not as immediately gratifying, is much more predictable. If he puts in the work now, it will pay off on the exam. Doing well on essays and exams will get someone a reputation for being a hard worker who is driven to succeed, no matter what the profs throw at him. This will cause at least one of the department's professors to notice the diligent student, and this can lead to recommendations for an internship, and perhaps even a sweet job or admittance to a prestigious grad school upon graduation.
One twin goes the party route. But partying puts a lot of demands on him. He often shows up to class late or hungover. He starts to get behind on his work as a consequence. Sometimes no amount of BSing can make it seem like you know the material, and this is the case with this dude. It doesn't matter if he's eking his way through school with Cs or not - the professors regard him as just another seat warmer. But on the bright side, he has a lot of friends from all around the country. He's seen his pals through thick and thin, and he believes he has seen much more of human nature than he could learn in his psych book anyway. Over his college years, he has amassed many stories about the human condition. He compiles these into a book, which he sells and markets to the general public. Many directors have expressed interest in making a film adaptation.
The other twin studies his hardest. Unlike his brother, this guy does not have as many friends, as too much extracurricular stuff distracts from his single-minded desire to succeed at his major with flying colors. Because many people interpret such behavior as dorky and lame, he has a few close friends, who are also driven to become great psychologists. The guy does get recognition from his professors. He gets an internship with a small psychological survey company that is up and coming in the field, and renowned for its attention to detail and proper statistical procedures. This looks really good on his resume and marks him as someone with potential. He gets into a really good grad school and later becomes a renowned professor. People want to hear his insights at TED and other conferences, and serious scholars read his scholarly articles and books.
Here's the catch. Even though both of these hypothetical people ended up successful, they can not go back and do it over again. Both of their attitudes towards psychology and their findings were indelibly shaped by what activity they prioritized. Even if the partier wanted more recognition in academic circles, it's not like he could go back and redo it all. Studying more would mean he would have less time with his friends. Maybe he wouldn't have gotten that girlfriend who taught him many things about love. His book would be weaker as a result. If he went full-blown academic, he would have ended up like his brother, and his book would not exist. The same could be said for the other twin.
The point is, your experience defines you. Your past defines you. This cannot be changed. In fact, society's past defines you. Surely a lot would be different if 9/11 hadn't happened, and it's only been 9 years. Would there be full-body scanners at the airport? Or would there have been a worse attack instead? What if Al Qaeda waited until they had an atomic or biological weapon? We will never know, but what we do know is that our lives are still profoundly affected in a myriad of ways as a result of that attack.
This is what happens with your brain as it gains new perspective. New information is compared with old information. Your mind does not exist in a vacuum. Someone could tell a creationist like Ken Ham or Ray "Banana Man" Comfort all the many ways their viewpoint is illogical, and they will think that person is mistaken, because they have
seen the hand of God the designer, and they have incontestable evidence to back it up. They have a certain view on life, and it has been shaped by their collective personalities and experiences. They could be dead wrong all they want, but the fact of the matter is they do not think they are mistaken. If Banana Man ever thinks he is wrong, he will change his viewpoint. But even if he becomes an evolutionist, his reasons for doing so are based on where he thinks his previous viewpoint went wrong. His new theory would try and make sense of all the times he's interpolated the hand of God. He will choose the best theory that explains what he's seen. It's not like people who change their minds about something are given a new brain. In this day and age it is silly to even consider that.
So why wouldn't type be otherwise? At its essence, type theory of any sort, no matter how mistaken, is making assertions that humans can be categorized. A phenomenon has to be predictable enough to warrant such a claim. Everyone can see that humans have some fundamental differences, and that a quiet child usually ends up a quiet adult. Even if the quiet child turned into an articulate adult, a person can still see that while the former child is now more confident in social situations, the adult still needs time alone to recharge.
This is why an articulate introvert does not an extravert make. A sensor can learn to make sense of the patterns around him, but that does not make that person an intuitive. It just means that the person's view has expanded with age and time, which is what people long to be. At their core, people want to be great. They want to mature. What they want to excel at is based on what they are naturally good at. This is what they prioritize, just like how the first twin went to the parties and the second twin studied hard. Someone like me will always prioritize patterns in the external environment, which is probably why this contains so many damn metaphors. A child INTP might not have all the details down pat on what is logical and what isn't, but they will still be focused on their personal logic. An INTP's logic can expand, and this is done by developing the lower functions. An ISFP's personal values also expand in this fashion. This is the difference between a Super ISFP and a mediocre, overly emotional, unfocused, inarticulate, sensual dilettante ISFP.
People expand. This
is change, but this change process is like the change processes elsewhere in the universe. Look at any chemical reaction. You can't end up with magnesium if there wasn't some magnesium in the original set of materials. Everything our brains encounter is like a chemical reaction, refining what we are the best at. But becoming better is not becoming totally different. We have to know where to look or it's all chaos, after all. Life as we know it would be totally different if it rested on this entirely different axiom you are proposing we consider*.
*Cool! That bear just turned into a tiger! Awesome! What will it change into next?! *dun dun dun!* I've always wanted a
crocoduck for a pet...