That's actually not true CTD. It would be more appropriate to say, the only experiences we can fully comprehend exist within our 3D perspective of space, and within our abilities to comprehend.

We, as human beings actually have very little capacity to fully experience all of the things that science has truly discovered, truly discovered. Take light as a simple example... colors. There are so many colors available within the spectrum of light, and they can be measured and they can be viewed, with some help (filters) here and there as we know how to proceed in that direction to view things (infrared for example). But as human beings, our eyes can only perceive so many colors within the spectrum of light as we know it/ We cannot see infrared light with our eyes, yet there is no doubt this wavelength exists. Science so far has measured an enormous quantity of available light waves, now don't quote me insofar as exact numbers but it's along the lines of something like 100,000 various different wavelengths (infrared being one, blue another. red another, and yellow for instance) and we view our entire human existence-experience with only three, the blue, red and yellow. A teeeny teeeny fraction of available light wavelengths are available to our eyes.

Sound is another example. sound actually has sort of volume, but we only perceive that part of the volume which intersects our space in a certain way and vibrates our eardrums in ways that we recognize.

these things are not imaginary CTD. The list is quite long.