You have NEVER in your life, nor has anyone atleast known, ever tried to honestly see in 4d. Because you have YEARS of your brain saying - NO, this is not possible, this can not happen. You can throw a thought of "Oh, this is possible" on top, and think you are saying that, but you'd be ignoring the experiences and memories and your entire life being based on 3d, which isn't possible that I can see.
What is 4d? 4d is a bunch of 3d objects stacked on top of each other. So while you only see in 3d, while you only recognize 3d, it doesn't mean you aren't in a 4d world. Because you are. You even more around in 4d, but your perception keeps a steady base of 3d, and as a result you only see or perceive in 3d.
What I mean is that you exist in multiple 3d realities, not just the current consciousness you have. How you move in the 4d realm is dependent on the choices you make, and the feelings you have. You do this, you just don't realize it. My future is not the same as your future.
This is commonly referred to as time lines. Each 3d reality is it's own time line, stack them together and you have 4d. It is thought you are stuck to a single time line, that's not true. You are only stuck perceiving your life as a single time line.
This is where free will and choice comes in. But it's not a matter of thinking or saying - I want this. 4d would make up the closest "alternate" time lines. So, if you move your arm 1 direction, you go down 1 time, when you move the arm in another direction, you go down another timeline. These things are small changes in the timeline, and so doesn't affect the overall outside timeline very much. But over "time" you can path down timelines which change dramatically. Of course, as with all things when you want to change directions or get a certain point, a valid path has to first be found.
So, if you develop the ability to say levitate an object. Eventually that will be available to everyone(you can call it the 100 monkeys theory if you want). But in reality, you've merely traveled down a time line that allows it, and the 100 monkeys theory is just part of the path.
Oddly enough, ancient religions say just this, although not so obvious. When you do good things, the timeline you are in reflects it. When you do bad things, the timeline reflects that as well. You can call the timeline the punishment, reward whatever. You can also see this in visual terms, go murder someone and your timeline will have you in prison. Keep being bad, and everything will get worse around you, until you reach a point where you just can't take the evil around you, and therefore you react with being good, which rises you through levels.
I don't know how old some of you are. I imagine a broad range. I'm currently 30 years old, and this is what my life has taught me. I only wish religion had taught me this, rather than to be fearful and do things out of fear, which had me ending up learning this lesson the hard way, cuz I don't do things out of fear.
You can experiment with this yourself. It's a little slow and hard to recognize at first, but it picks up pace rather quickly. The hardest thing is stopping letting people control or affect your emotions and thoughts, which is usually done with fear. Fear of being robbed, makes you angry, makes you judge, reflects that back to you in the mirror(timelines you choose).
Hope that makes sense.