Precepts that seem obviously obvious may be adopted without question. Revolution will follow once the flaw is exposed. Where conceptual skyscrapers have been built upon insecure foundations, the upheaval will be severe. Gestalt psychology reminds us that the whole is not simply explained by the sum of its parts. Our cultures ensure that we interpret all facts in the light of some preconceived and distorting perspective.
Science grows through many discrete bubbles of expanding knowledge.
These bubbles eventually meet and coalesce but, before doing so, the perception of a particular discipline may be both parochial and distorting. My proposition is that we have. It is accepted, more or less without question, that T-cells and antibodies have both evolved and been designed to identify, then eliminate, foreign organisms. But, consider this point. Not all micro-organisms make us ill.