That’s not really what they’re trying to say; that is an oversimpilification. I suggest a pair of common phrases that better represent what the authors are saying: • It’s complicated • More research is needed I admire that the authors are presenting facts where they know them, make correlations where they may be made reasonably, and admit/point out where more information is needed. This is the foundation of useful science. If instead they approached the issue with foregone conclusions, they would be doing all us readers a severe disservice. I find it refreshing to find, among an internet full of misinformation, articles grounded in intelligent thought based on logical processes such as this one. The only motive here is to discover facts. Being able to admit you don’t have all the answers yet is the right answer when correlation does not equal causation.