De Novo Origins of Multicellularity (How to test a hypothesis)


(Matthew Pevarnik) #1

Scientists work hard to test hypothesis:
One of the things that I love about science is the hard work that scientists go through to test their hypothesis. It is something that I find lacking from many pseudoscientific or a quasi-scientific or anti-scientific, etc. movements. For example, the essential oils community is convinced that they are quite effective in being able to alleviate symptoms or attack viruses or boost immune systems. However, outside of maybe a petri dish study, there seem to be a severe lack of publications of their efficacy in real human beings. Go do the study- it will show effects beyond statistical blips and placebo if it does what is claimed! I’ve seen Christians put up remarkable graphs and find that they are based on no actual publication at all but a back of the envelope calculation. When I asked them why don’t you publish this it would be really quite remarkable they replied it would be too hard to do it (my addition: with the rigor demanded by the scientific process).

An example: testing hypothesis on the origins of multicellularity
One example that caught my eye recently was this one where the origins of multicellularity is an outstanding question of science- we don’t have much evidence from the fossil record or genomes (though some really cool clues perhaps for another post). One hypothesis centered around that there was selection pressure from some sort of single celled predator. But without more evidence you would have to be rather tentative with your hypotheses. So how could you test that hypothesis? Well put some predatory cells with some unicellular cells and wait hundreds and hundreds of generations! What might one find?

https://www.nature.com/articles/s41598-019-39558-8

Is this what ultimately happened on earth hundreds of millions of years ago? We may never know but it is a direct test of a hypothesis where the abstract summarizes:

These results support the hypothesis that selection imposed by predators may have played a role in some origins of multicellularity.

One more thing that I love is how scientists tend to not conclude more than what their experiments actually can demonstrate. Sure some when talking to the public may be more grandiose but there is a humility to the process that non-scientists can be unaware of.

Thoughts, examples? Did I speak erroneously at some point? Let me know!


(Mitchell W McKain) #2

Yes… but it is a technical point where you may be a little misleading, though possibly unintentionally…

Scientist claim way too much all the time. People are people after all. Yes there are great examples of humility in the science. But the same is true in religion. My-side bias aside, I am willing to bet the people in both groups are pretty much the same distribution with regards to humility, honesty, and everything else. The difference in science, and in some ways you can compare it to the checks and balances in democracy, are the methods by which science insures the honesty and veracity of its conclusions. Peer review is big part of it, but it is a first filter only and it does have flaws. Far far more important is the fact that science requires written procedures which anyone can follow to get the same result. And on the forefront of scientific inquiry you will ALWAYS find people checking those result themselves because it is how scientists all over the world in the same area of inquiry advance their own understanding and ability to make their own contributions, which will include corrections to the claims of others. Among other things, this is driven by students seeking PHDs who can only get those PHDs by making such a contribution.


(Matthew Pevarnik) #3

Do you have some specific examples in mind that could be helpful for others (like myself) to keep in mind?


(Stephen Matheson) #4

I think the important point here is “a humility to the process.” As people, scientists have to worry about cognitive bias and struggle with normal and even extraordinary pressures to exaggerate or overinterpret. My impression is that scientists as a population do exercise more intellectual discipline than many subpopulations of non-scientists, and sadly evangelical Christianity is an example of intellectual corruption on spectacular scales. But it’s the process–and perhaps more notably the social community values and disciplines–that add up to collective humility. Thanks for making that point.


(Stephen Matheson) #5

“All the time” is way too strong. The kind of responsible equivocation that you highlighted in the OP is commonplace, so exaggeration “all the time” is the opposite of the truth.

One reason, though, is that the community has mechanisms for teaching and enforcing these values. A secondary but non-trivial aspect of my job is to be one of those enforcers, along with expert reviewers, to ensure that evidence and claims are reasonably aligned. Unfortunately, and to our regular frustration, we have no control over press officers at institutions, to use the most common example, and IMO this is where the most troublesome overstatements come from.


(Mitchell W McKain) #6

The quantity depends on what stage of the filtering process you are looking at. “All the time” is only an exaggeration if you look at a later stages of the process. The point is that scientists are human beings and it is the process of science which makes the difference not the people. To be sure those with experience know what to expect and so the professors are often the first and biggest filter who will reign in their student researchers.

Yes. There is not much filtering when it comes to the press. You also need to discern that scientists who publish popular books outside the peer review process are not going to be very restrained in what they write there either, often not even confined to their field of expertise. That would be a good example of scientists claiming too much “all the time.”


(Mark D.) #7

I think what is positive about the way science is conducted is that it would never lead anyone to self deception. It can’t always prevent it, but it can never be used to justify an incorrect approach such as creation ‘science’.


(Stephen Matheson) #8

I’ve been a part of every stage of the process. “All the time” is a laughable exaggeration.


(Mitchell W McKain) #9

Looks like my-side bias in full-blown action to me. Or… maybe the exaggeration here is in your literal interpretation of the idiom “all the time.” The point was, it is not the people but the process. Your reaction is suggesting otherwise and that is my-side bias in action.


(Matthew Pevarnik) #10

I didn’t see any specific examples that you listed of how scientists go beyond what the data permits all the time. Did I miss any that you gave?


(Mitchell W McKain) #11

I guess you did.


(Matthew Pevarnik) #12

Right I mentioned that:

I could have been more clear that this includes popular books when I wrote it. Outside of that though do you have examples?


(Mitchell W McKain) #13

Why would I need any other example? That is a perfect example to show that it is not the people but the process.

But ok… There was a particularly spectacular example right here where I am from in Utah with claim about having solved the problem with cold fusion. Of course it could not stand because the process precludes it. Again the point is that scientists are people and people can naughty in many many ways if you let them get away with it.


(Matthew Pevarnik) #14

Sure but this was about scientists being careful with conclusions in actual scientific studies, not the grandiose claims that can be made in public discourse.

Their interpretation of their data was wrong in the cold fusion fiasco, but I don’t quite see how this is akin to what quasi-scientists or pseudo scientists do. There was some evidence that could support their hypothesis but at best this could be a nice example of peer review occurring after the initial publication. In hindsight, I thought this was a neat summary over 25 years later:


(Mitchell W McKain) #15

You made it about that not me. For me it was about people versus the method.


(Matthew Pevarnik) closed #16

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