The Flagellum is Not a Motor?


(Herculean Skeptic) #184

To be 100% fair to @swamidass, it started off to be about whether or not the flagella is a motor, but later it became about whether or not it was legitimate to use the word motor as a descriptor or name.

(John Harshman) #185

Perhaps everyone should start by defining “motor”.

(Herculean Skeptic) #186

That’s problematic. It has to be the standard, run-of-the-mill definition, else it cannot work as a name. And the name (or label “motor”) seems to be ubiquitous, even among scientists.

(S. Joshua Swamidass) #187

@DaleCutler, the point is that there ARE similarities between a designed motor and a flagellum, but there are ALSO differences. The differences are large and important. There are differences also in how the individual parts function, the nature of the “power source”, the complexity level, the complexity of a minimal flagella, the way it assembled, the way it arose, etc. etc. etc.

You can’t enumerate the differences, there is no reason anyone should believe you can even assess if the analogy is relevant to ID. The fact it has a different ontology, for example, is highly pertinent. You dismiss it as irrelevant, but that is disingenuous as best. Actually, it comes off worse than this…

My point is the same as the beginning. Sure, use “motor” as a rough analogy of a flagellum, but you don’t really know what a flagellum is unless you can also enumerate disanalagies. The differences are so substantial as to render the analogy to a motor misleading (at best) when used in the ID argument. I don’t think you are being dishonest, but that you just don’t really know much about the reality of what a flagellum is and how it works. That is why you are struggling to enumerate the differences.

(S. Joshua Swamidass) #188

I meant it was not a “motor” in the way it was being used by @bjmiller (and then @DaleCutler). As I explained repeatedly in the initial post and afterwards, there is poor grasp of the disanalogy to a human-designed motor, so they were falling prey to the idol of the marketplace. It appears I was correct.

Sure, use the word “motor” to describe a flagellum if is helpful. However, have a solid grasp on where the analogy fails or you are going to make dumb arguments with it. That has been my point from the beginning. It is fairly remarkable how such a trivially true statement becomes so controversial.


It seems like a lot of people are terrified of saying that the flagellum resembles a motor because then someone’s going to say, “motors are designed!”

Ok…the flagellum resembles a motor. It was designed…through evolution: self- organization, emergence, “smart cells,” horizontal gene transfer, exapation, transposition, etc. with it’s final cause (in the Aristotelian sense) being God. Seems quite likely to me.

(Dale Cutler) #190


(Dale Cutler) #191

That is the way I was using it, not as you are characterizing it.

(Dale Cutler) #192

I’m with @Mark to that point, for sure, and I believe it was @swamidass’ extrapolation from something I said that has caused the ruckus. :wink:

(…not to mention shifting from function to ontology and back. :slightly_smiling_face:)

(S. Joshua Swamidass) #193

@DaleCutler, your last three posts are unintelligible to me. I disagree with how you and @bjmiller and I are using the analogy and do not see an error in the quote you are regurgitating back to me. What exactly is your point?

Huh? What is your point?

You posted this, remember…

Which seems obviously false to me.

Not really.

(Dale Cutler) #194

My point is that I was not talking about design, but function, and you just inferred it from the analogies.

(Dale Cutler) #195

The Flagell[um] is Not a Motor

Functionally, yes it is.

(S. Joshua Swamidass) #196

Are you even reading what I wrote?

(Dale Cutler) #197

All you have done is allude to differences, and when pressed, you gave two differences that were ontological, not functional, embellished with disparaging remarks.

(Dale Cutler) #198


Bacterial flagella grow through an injection-diffusion mechanism | eLife


its true that all things may be the result of design. but if we was lived in a world that only has pile of dirst instead of living things- i dont think that i was argue for design at all.

(Herculean Skeptic) #200

@swamidass I appreciate your offer to evaluate differences between the two. I don’t know why @DaleCutler didn’t wish to take you up on the exercise, but he (or anyone else) can feel free to jump in and add or edit the list that I came up with.

Similarities Dissimilarities
Rotates Helical access at different angle than shaft
Drives a propeller Runs on protons or ions vs. magnetic field
Contains a mounting plate (front bracket) At high loads, more components become active
Contains a rotor. Rotor configuration is variable.
Contains a stator. Both bearings are at one end of shaft.
Direction (rot.) is based upon rotor config. Made of protein, not metal.
Has two bearings. No start circuit/run circuit (only one, single circuit.)
Has a seal mechanism to prevent fluid intrusion. One is living, the other non-living.
Equivalent power to turboprop engine (5HP/LB)! Runs nearly continuously (~26 discrete steps.)
Continuous duty. Water cooled vs. air cooled. (Not really a difference because it is cooled by the medium in which it runs.)

Please let me know your thoughts about this list. Are these the types of similarities and differences you were considering? Or others?

(Dale Cutler) #201

Thanks, really interesting. The reason I didn’t take him up on it was because the question at hand, I thought, anyway, was whether a bacterial flagellum was a motor or not, per the conversation’s title. I thought he was looking for differences in function and reasons why it was not analogous to a motor. And nearly every one of the differences you’ve listed is analogous, though, just different.

I differ with you on one detail, anyway: flagella, in some species, anyway, are briefly reversible:
“34.4.3. Bacterial Chemotaxis Depends on Reversal of the Direction of Flagellar Rotation”
A Rotary Motor Drives Bacterial Motion - Biochemistry - NCBI Bookshelf

(S. Joshua Swamidass) #202

You don’t read what I say very much do you? I’ve explained over and over that we CAN call it a motor, but only if we understand the disanalogy too. I give @Michael_Callen credit for trying, but there is much more to discuss about it. It is telling that you still have avoiding engaging the details. It turns out that your assessment is just false. It appears you don’t really know what a flagella is nor do you really care to learn.

Also @DaleCutler, this is not an insult or condescending, it is just reflecting back to you what your behavior seems to indicate. You could always try changing your behaivior.

(Dale Cutler) #204

That rather set the tone for the whole discussion. You have three fingers pointing back at you.