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Oh I really enjoyed this one. Got a quick insight about how penicillin works: interferes with cell-wall building which is a destroy and recreate process by pre
by arjie 11mo ago
Oh I really enjoyed this one.
Got a quick insight about how penicillin works: interferes with cell-wall building which is a destroy and recreate process by preventing the recreate part.
Got a quick view into the scientific process and communication: Fleming focused on the insight - penicillium kills staphylococcus - and left out the circuitous detail. This is important so that the big win here is very clear.
And got an insight into human nature and memory: Fleming didn’t tell the accidental contamination story until much later. It could possibly be even an idea someone else might have come up with which then took root in his mind (ironic haha!)
The communication aspect reminds me of Mendel’s far too perfect ratios for his pea plants. That kind of “repeat till difference clear” statistics would be decried today but perhaps that was to communicate rather than to determine.
And finally, I really enjoy reading about human process innovation because I think it’s a big factor in how Humanity grows. The lab notebook has to be some kind of star performer here - Fleming’s notes allow us to look back like this.
When I experiment with things, I naturally lean to keeping notes on my test protocol, observations, and results. But not because of some personal genius. It’s just the standard way I was taught as a child in our science labs.
I won’t claim to the rigor of a microbiology lab but even just the process notes help a lot, which is useful since I’m just testing molecules on myself.
- Joker_vD 11mo ago> Mendel’s far too perfect ratios for his pea plants. "Remember, if you flip a coin 200 times and it comes heads up exactly 100 times, the chances are the coin is actually unfair. You should expect to see something like 93 or 107 instead".
- fainpul 11mo agoIsn't 100 / 100 the most likely outcome for a fair coin? Sure it's unlikely that you hit exactly that result, but every single other result is even less likely. What I'm trying to say: if you get 100 / 100, that's not a sign of an unfair coin, it's the strongest sign for a fair coin you can get.
- Joker_vD 11mo agoWell, yes. But the expected deviation from the mean is still ≈7.07. And the probability that the outcome will be either 93/107 or 107/93 is (slightly) higher than the outcome being exactly 100.
- fainpul 11mo agoBut those are 2 results. 100 / 100 is more likely than 93 / 107 (or any other specific result) is what I'm saying.
- Joker_vD 11mo agoDepends what you count as a result, I guess. "There is exactly N flips of a single kind" is also a viable definition, just as "The exact sequence of flips was x_0, x_1, ... x_199" is.
- paddleon 11mo agoYou can tell the difference between 93 heads, 107 tails and 93 tails, 107 heads but not between 100 heads, 100 tails and 100 tails, 100 heads. So while those are two results (93/107 and 107/93), they really only count as two separate outcomes if you pre-specify that the first number is heads. If instead you consider symmetries, where there are 2 ways to get 93/107 and only one wall to get 100/100, then you have more likelihood for the 93/107 outcome because you have two ways to get it.
- deleted 11mo ago[deleted]
- kalaksi 11mo agoI don't think that makes 100 / 100 the most likely result if you flip a coin 200 times. It's not about 100 / 100 vs. another single possible result. It's about 100 / 100 vs. NOT 100 / 100, which includes all other possible results other than 100 / 100.
- munchbunny 11mo agoThe chance of exactly 100 heads from 200 fair coin flips is approximately 5-6%. Qualitatively, that's not particularly strong evidence for an unfair coin if you did only one trial. You could also argue that 100 out of 200 on a fair coin is more likely than any other specific outcome, such as 93/200, so if the argument is that the coin is "too perfect", you then also have to consider the possibility that the coin is somehow biased to produce 93/200 much more often than anything else, vs. 100/200.
- nearbuy 11mo agoThere is also no way to weight a coin that makes it more likely to get 100/200 than a fair coin.
- n1b0m 11mo agoIn a real-world scenario, if you saw a result significantly far from 100 (like 150 heads), you might suspect the coin is unfair. However, seeing exactly 100 heads gives no reason to suspect the coin is unfair; it's the result most consistent with a fair coin.
- stevenwoo 11mo agoIf you are not familiar with more of Mendel or plant biology, he got extremely lucky in picking a two chromosome species. The next plant he picked had more than two chromosome types so he spent the rest of his life hitting his head against the wall - obvious to us but him not having a theory and expertise with microscopes to explain his pea results hampered him greatly beyond his initial pea plant studies.
- dexwiz 11mo agoWhat do you mean by a two chromosome species? A quick google says pea plants have 14 chromosomes. I only looked because I had never heard of a species only having two chromosomes. Do you mean the traits he was selecting for only had two alleles?
- stevenwoo 11mo agoRight, my bad for wrong terminology as biology nor botany is not my speciality either. I was thinking along the lines of XY for humans, then the ordinary two row, two column chart used to teach the basics of Mendel with pea plants and dominant/recessive non polygenic traits in introductory biology classes.
- dekhn 11mo agoThe traits he picked- hope I get this detail pedantically correct: had only two alleles, each allele had an obvious phenotype controlled mostly by that gene, the two phenotypes were binary (no intermediate "half-wrinkled-half-smooth"). and all segregated independently (different chromosomes, or far enough that the linkage was extremely weak). I remember my high school teacher speculating he inspected many different phenotypes and then reported his results on the final ones he picked where the results were nice. Unfortunately, most modern genotypes and phenotypes in humans don't follow these patterns, and over the years, genetics devloped an entire vocabulary and physical model to explain them, although at a fairly abstract level. None of it made any sense to me so I follow the biophysics/molecular biology approach which tends to consider many more underlying physical details There's a related story, https://review.ucsc.edu/spring04/bio-debate.html https://review.ucsc.edu/spring04/bio-debate.html and https://review.ucsc.edu/spring04/twoversions.html https://review.ucsc.edu/spring04/twoversions.html which shows how different fields think about the genotype/phenotype relationship. Grinding up steering wheels to figure out how they work...
- awkward 11mo agoSo many other good details that get to how impossibly multivariate biology research is, like the need to have several days at the exact temperature. It's not uncommon for results in biology to have this kind of snag in reproducibility even now. Sometimes it's due to attributing variations to something like "steady hands at the bench", but other times it can even be a deliberate attempt to prevent rivals from duplicating a process before it can be patented and privatized.
- microtherion 11mo agocf The Harvard Law: "Under controlled conditions of light, temperature, humidity, and nutrition, the organism will do as it damn well pleases."
- kcexn 11mo agoIt's a shame that Fleming misremembered his process of discovery and created a myth of accidental discovery. I like the Root-Bernstein narrative more. That in the monotonous execution of routine experiments for something unrelated an unusual observation 'forced' them to discover penicillins antibacterial properties. Not an accidental discovery by good fortune in a serendipitous sense. An accidental discovery of a brute force exhaustive search. The narrative of we spent months meticulously examining hundreds of samples is less romantic, but is one that supports the importance of funding scientific inquiry. We won't make progress by hoping people leave culture plates out on window sills. We make progress when we fund meticulous exhaustive efforts of discovery.