I was going to ignore additional posts, concentrating on the four answers I discussed, but I love debating Linda so much that I couldn't resist answering her post. The main reason is when we debate in person, she always interrupts me; this way I can say what I want without intrusion, although I am sure I won't get the last word! ;-) I won't copy Linda's post. If I did, this reply would be too long, so just look her original. I hate to accuse Linda of nit picking, but while quibbling about precise definitions in a scientific paper has some merit, on the FML it is pointless. Converting a scientific paper into a paper that meets the language constraints of the majority of FML readers, while meeting Bill's very necessary limitations on line length and number of posts, can be difficult. I am ALWAYS trying to decide what I will cut out to meet line length requirements. I have noticed nearly EVERY complaint lodged against me (by Linda and others) has been the result of cutting explanatory text to shorten line length. Reducing text from precise scientific terminology to a more inexact lay terminology introduces imprecision: the root of Linda's eloquent objections. It is a fine line to walk between the two styles of writing, and I am not always successful. Nonetheless, most of the objections are moot because while they may cause a minor clarification, they do not illustrate a fatal flaw in reasoning (you may disagree). Still, Linda brought up one point that deserves a detailed response. I think what Linda was trying to say is, and please correct me if I have misunderstood, that if the knowledge of a ferret's nutritional needs are unknown, how do we know the natural diet is a better one? This is a fantastic question, and I am pleased Linda recognized it. The implication of Linda's question suggests an evolutionary diet may NOT be the best diet for a specific animal. I don't think Linda really believes that, given the last part of her post. I think what Linda is trying to do is to break my chain of argument in an attempt to disprove or minimize my conclusion that a kibble diet is unsound (this is the point I would attack). Unfortunately, the argument misses the point because even if the evolutionary diet is not optimal, ferrets are still better adapted to a natural diet than a modern artificial construct containing processed nutrients in amounts in excess of a ferret's nutritional requirements. In other words, even if the natural diet was not perfect, because polecats have obviously adapted to it for at least 10 million years, it is STILL the standard to measure all other diets. Ferrets are so well adapted to a diet of flesh that they have lost all their molariform teeth, excepting a few small molars used to crack hard objects, chiefly snail shells, insect and crustacean exoskeletons, and bones. They have a simplistic stomach, lost a functioning caecum, and have an extremely fast gastrointestinal transit time. They have a stomach with a very low pH (acidic), and a pancreas and hepatic system designed to process high amounts of protein. They have a hormonal and enzymatic system designed to digest flesh. They have relatively few bacteria in their gut, and are extremely sensitive to bacterial overgrowth in that region. They have reduced requirements for fiber in their diet. They have lost the ability to synthesize numerous amino and fatty acids, and have high requirements for trace nutrients found aplenty in animal carcasses. In short, they are an animal superbly adapted to a diet of flesh and bone: the consummate carnivore. Regardless of the exact composition of nutrients found in prey animals, the diet is STILL the standard of measurement because it reflects the one the ferret is best adapted to consume. At another level, the objection misses the point because it creates a set of implications that cannot be tested. Hypotheses are not actually tested; rather, scientists test the implications of a set of hypotheses (null and alternative), using generated data to falsify one or more possibilities. You can compare kibble to a natural diet, generate data, and make conclusions, but how can you test a natural diet against some nebulous "other" possibility? It is not an alternative hypothesis unless you can test it; if you want to imply the evolutionary diet is suboptimal, then you accept the burden of proof to show it's failings. In other words, it is not enough to simply imply the evolutionary diet may not be optimal; you need to supply some evidence other than supposition to show such a hypothesis has merit. Just because it may or may not be true in giant pandas (or ANY other genus) doesn't make it true in ferrets. A herbivorous diet in pandas, separated by at least 14 million years from other carnivores, is a poor analog for a strict carnivorous diet in polecats that evolved as primary, obligate carnivores. Excellent debate, Linda; I had to really think to make a reply. If we were facing each other in person, we could dissect this down to infinite detail and maybe I could convince you, but space is limited, and we are probably boring FML membership. Most of your other points will be covered in future posts, and I will put off answering them until then. Bob C [Posted in FML issue 3948]