The author distinguishes a stable finding from a complete explanation. In fungal nutrient networks, isotope tracing shows carbon and nitrogen moving through fungal connections between plants, so the author treats the claim that fungal networks can mediate nutrient transfer as well supported. But the author also says that the question of how often the transfer changes plant competition in natural forests remains under investigation and that mesh experiments alter soil structure while excluding some organisms. The passage therefore rejects both the claim that nothing is known and the claim that all details are settled.