Our learning (both as individuals and as a species) almost always happens out on the margins. Rarely is new learning the result of some sort of epiphany or remarkable contradiction to what we already know.
The human brain is constructed in such a way that makes it naturally curious. It constantly compares what we already know with novel experiences/knowledge and attempts to "square it" with our previous understandings.
A most fundamental form of learning is what we call "common sense." It's the intuitive understanding we glean from simply living the human experience. We all have a degree of common sense (though some seem to possess a deeper well of it than others).
The most technical and disciplined version of learning is the scientific method -- identify a pesky problem, affix to it a testable question, design an experiment to test that question, scrupulously measure the results of that experiment, draw defensible conclusions from that data, and finally, put those results in front of many bright minds so they can either shoot holes in it or agree.
In both common sense and scientific research, our learning persistently occurs out on the margins. We tinker on the edges, constantly pushing the knowledge boundaries outward, bit by bit.
Problems arise when we cease the curious inquiries that afford us the incremental new knowledge that makes us smarter, healthier, more capable - in all our human dimensions.
Anyone that tells us the learning is complete (in any domain) is either delusional or has nefarious intent.