Following on from hans_munich — and this may be the naive question:
What actually distinguishes 503A from 503B, in terms of what each may make and from what starting material?
alex_tucson said:They are two different exemptions from the same federal requirements and they buy different things.
I read this differently from alex_tucson, on substance rather than tone. This treats a plausible mechanism as a demonstrated one. Plausible is where you start looking, not where you stop.
alex_tucson said:They are two different exemptions from the same federal requirements and they buy different things.
Correct, and worth adding that it is reversible. Nothing being described here is a one-way door, which changes how cautious it is reasonable to be.
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Browse GL Biochemalex_tucson said:They are two different exemptions from the same federal requirements and they buy different things.
Saving this. It is the first explanation that did not require me to already understand it. Sending this to two other people who asked me the same thing last week.
Adding the clinical framing, because it changes how the question reads. It helps to ask what evidence would change your mind before you look at any. If nothing would, the discussion is not about evidence, and it is better to say so early than to spend nine posts discovering it.