Science: the strong and weak forms

So I've just been skimming through the memoir of Ro Lowe-McConnell.  Will have more to say when finished with it but already it is proving very interesting.  Ro did a study of Lake Malawi's Tilipia just post WWII.  Tilipia at the time were thought to be the Lake's most important fishery and Ro, a fish biologist, was sent by the British colonial government to learn more about them.  One of the most interesting things about the book so far is the tension that exists, if one looks for it, between what one might call Ro's "strong" scientific statements and her "weak" ones. An example is illustrative.

In chapter 2 Ro states that "we now know that this Lake [Malawi] has more species of fish than any other lake..."  This is quite a strong statement of scientific fact i.e. "we know...."  Yet in her introductory remarks to the book Ro makes what I would call  "weaker" statements of scientific fact that are in large measure contradictory to her chapter 2 claim "to know".  In those remarks she talks about the "fragility of the scientific edifice" particularly in regards to Lake Malawi's taxonomy and how in its current form that taxonomy "may be transient" because it is based on "techniques of [a] time" now past and finally that at any rate "the concept of the species is fragile in such a rapidly evolving group as the cichlids [which constitute roughly 90% of the Lake's fish diversity]."

So which is it?  Does the Lake have more species than any other lake or given the "fragility" of the species concept for Lake Malawi, should we be more circumspect in how we describe the lake's diversity?

Now certainly we know which statement is the one most frequently heard today.  Repeating the assertion that "Lake Malawi is the most biologically diverse lake in the world" has been the sine qua non access key to vaults of funding for evolutionary biologists wanting to do research on the lake for at least the past 40 years.  It has also been critical to the development of Lake Malawi's cichlid fish into sought after international commodities in the aquarium trade in the West and as a tourist and conservation attraction in Malawi.

But what about that "weaker" statement?  Well if pressed I suspect Ro would have stuck to it more than the stronger one, but society and scientists themselves tend to be uncomfortable with modest statements particularly when interests, both monetary and professional, are at stake.

I'm sure there will be more to come.

Science: the strong and weak forms