Knowing vs. Articulating
Some people seem to possess the type of knowledge that is difficult to articulate: a vague dread that comes before a natural disaster, a strange love of something or someone, a vision of the divine. You might ask people possessed of such knowledge about it and they might answer, "I can't explain it; I just know it."
This type of argument is very thin when the question is "What is your control group" or "What makes x a reasonable assumption?" To such questions, you should be able to articulate a 1-sentence answer.
If you find yourself unable to articulate answers to questions about your research, don't kid yourself that you are the guardian of some arcane knowledge. Instead, work hard to articulate till you know your work well enough to explain it to a duck.
Blog Post: Varanya Chaubey Image: Thomas Jones [Public domain], via Wikimedia Commons