I opt for renaming the (Bouguer-)Beer-Lambert (BBL) law and suggest "Ideal absorption law". Why? There are many parallels between the ideal gas law and the ideal absorption law, e.g. that both are more or less valid for diluted gases. But nobody would mistake the ideal gas law as a general valid law thanks to its name.
Quite the contrary in case of the BBL law, where whole (sub-)fields like, e.g., infrared spectroscopy of organic and biologic materials, are built on the general validity of the BBL law and only few know about its real limits...
Changing the name of a law creates chaos. People learning the concept for the first time - and so would not be taught BBL as the name) will struggle to comprehend past literature and different generations of scientists will get frustrated trying to share ideas.
I've seen this in my field - colloid science. The entire field has been taken over by nanoparticle/nanodispersion etc. Moreover, confusing new (and pointless) definitions make it very difficult sometimes to easily read papers etc. I've seen this result in new generations of scientists in the field make errors/lack understanding of the colloid science.
John Francis Miller I could not agree more with you if we speak about a prospering field based on sound theory which explains the experimental findings.
Not so in spectroscopy! Imagine you are a PhD-student. Your supervisor wants to expand his work from infrared spectroscopy of organic and biological matter to inorganics and you are the lucky fellow charged with the study of the "new" kind of samples. You take the contemporary textbooks (which means in this particular case those from the 60ies up to now), and try to apply the BLB-law, because, as you read, it is the fundament and cornerstone. Congrats! In this case, you are so far off the range of validity of the BLB-law that using it does not make any sense at all (happened to me 23 years ago... ;-)
Theory in spectroscopy is a desolate mixture of concepts that are compatible to Maxwell's equations and those that are not (to the latter the BLB-law belongs). There is certainly nothing wrong with using approximations, but you have to be aware that you are using an approximation and you must know the limits of it. Hence my suggestion to rename the BLB-law. Better an ending with some chaos than chaos without end... ;-)
What you describe is a good opportunity to teach something else that is valuable but often neglected. Teach the ideal law as BBL but emphasize it is an approximation and therefore useful under limited circumstances. Then teach the more appropriate theory, and compare/contrast the two. Knowing how to gauge when an ideal law is a good choice for your particular needs is a useful skill.
I dare to say (because I've seen it :) ) that with the explosion with online information (Google, Wikipedia) that has not been peer-reviewed, a laziness is creeping in that simply didn't exist when all you had to refer to were a few textbooks or lecture notes. This is hurting the development of analytical thinking skills.
Many thanks - I do this already since a couple of years, but it is the proverbial drop in the ocean. It goes actually much further than just the BBL-law, since, e.g., also the theories concerning linear dichroism are affected...
Concerning Wikipedia, I think we must take over responsibility and help to correct errors in there, keep it updated and add references that are peer-reviewed...
I feel it should be called the Beer-Lambert-Bouguer law, or BLB law for short. It was first discovered by Pierre Bouguer [Essai d'optique sur la gradation de la lumière, 1729) pp. 16–22.], then improved by Johann Heinrich Lambert [Photometria 1760] and finally in its present form by August Beer (1852). Thus the name would reflect the order in which it was discovered. There is more information about this here: https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law#History
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