[enw]

All these evolutionary arguments (e.g. “head of penis is shaped as such to clean out semen of competitors”) all sound conveniently convincing, but I’m curious if there’s any data validating them?

It’s easy to shoehorn any number of plausible theories, but how do we know one evolutionary theory is the correct one?

[perilunar]

These are often called "Just So Stories" after Kipling's book for that very reason.

See:

https://en.wikipedia.org/wiki/Just_So_Stories#Evolutionary_d...

https://en.wikipedia.org/wiki/Just-so_story

[taneq]

Clearly the arguments that sound less convincing have failed to survive and reproduce. The existence of evolutionary arguments is therefore proof of the correctness of the theory! ;)

[jojobas]

Except penises come in quite a variety of shapes across species. Distinguishing actual driving traits from those that just happened to ride along (i.e. men's nipples and other various vestiges, bright red colour of foxes where neither the foxes themselves, nor their predators or prey can see colour), is very hard.

[perilunar]

Memetic evolution of arguments about genetic evolution. Very meta.

[PartiallyTyped]

> but how do we know one evolutionary theory is the correct one

IMHO, the one that works is the one most likely to result in increased gene propagation even if the percentage is minuscule in the absence of orthogonal genes.

The argument is not that X evolved to do Y, but rather X resulted in increased gene propagation as it happened to do Y.

In the example above, the head of the penis is shaped as such because that shape enables semen displacement. In the same vein, males tend to lose an erection, and therefore the [flaccid] penis loses the displacement property, after excretion because that results in not displacing one's own semen.

[hsn915]

It's all guesswork. There is no mechanism to validate any of it.

[pvaldes]

Everybody knows that we evolved a smooth firm surface to attach wobbly eyes stickers and impress the females. Deeckaboo!. Is the magic of evolution

[LarsDu88]

Look into the genitalia of felids and other large mammals. It will start to become obvious how biologists may have come to that hypothesis!

[P5fRxh5kUvp2th]

We'll never know, honestly.

And if I'm being truthful, I struggle with evolution a bit. It's a bit like life. I understand how life could have eventually evolved to where we're at. But how did life _start_?

Any specific mechanism is explained as having evolved, but if so, how did it _start_?

For example, there's an HN thread explaining why bees die after they sting and why it's acceptable from a colony perspective. What put bee's on _that_ specific evolutionary track? How did it _start_?

I think a lot of people are like myself, there's a level of blind faith put into evolution. We obviously have witnessed it happening so we know it does happen, but there are so many things we can't explain for sure that forces us to have blind faith it happened via _purely_ evolutionary forces. like ... what if we find out some super advanced alien civilization seeded earth with life and managed it in some way, helping shape things. It would kind of explain a lot.

And so I continue to have blind faith that even if we don't have a concrete explanation for many of the things we see it happened via evolution, but I also understand the skepticism some people have for evolution being the sole explanation.

[mcphage]

> I understand how life could have eventually evolved to where we're at. But how did life _start_?

Evolution doesn't explain how life started (or attempt to explain), just how it changes over time. How it started is obviously a really interesting question, but not one you can use evolution to understand. Evolution explains a specific thing, not everything.

[dsego]

> there's a level of blind faith put into evolution

I'd call it common sense, more than blind faith. You see a person dead on the floor with a bullet wound, and a handgun laying next to the body. Concluding that the victim was shot to death is common sense, not blind faith. In that sense, evolution is more like playing detective, all the evidence is pointing to it.

[P5fRxh5kUvp2th]

Sure, if you find the phrase "common sense" to be less offensive than "blind faith", but in this case they mean the same thing.

https://www.youtube.com/watch?v=lFIYKmos3-s

[mcphage]

> in this case they mean the same thing

Blind faith implies both lack of evidence ("blind"), and rigid loyalty to a specific idea ("faith"). Common sense implies neither of them.

[P5fRxh5kUvp2th]

I see you didn't watch the youtube video I linked

https://search.brave.com/search?q=definition+of+faith&source...

> Faith

> 1. The assent of the mind to the truth of a proposition or statement for which there is not complete evidence; belief in general.

> 2. Specifically Firm belief based upon confidence in the authority and veracity of another, rather than upon one's own knowledge, reason, or judgment; earnest and trustful confidence: as, to have faith in the testimony of a witness; to have faith in a friend.

...

> 5. Intuitive belief.

We have a hypothesis that the penis _evolved_ due to it's ability to scoop out semen. A part of that hypothesis is that this is why longer penises evolved, to place semen in places that cannot be scooped out by other men.

But another explanation for larger penises is that women find them more attractive and pleasurable and therefore it increased your chance of mating.

Another would be that larger penises are statistically more likely to get a woman pregnant in general, with or without a bulbous head.

But here's one for you. The original hypothesis about the penis head came from an experiment in which they found that a single thrust could potentially pull out 90% of a competitors semen. We won't discuss the logistics (they didn't use real people), we'll have _blind faith_ that the experimenters ensured it was realistic.

Men ejaculate in spurts over a time period that is larger than what it takes to thrust a single time. This would imply the penis head also removes it's own sperm quite often.

---

The point here is that

1. We don't know, and 2. We can't know without actually documenting the process.

This sub-thread was brought about by someone saying "how do we know this is true", and the answer is, we can't know, therefore we take it on blind faith.

If you're offended by the phrase blind faith, use whatever phrase you like. But while you're doing that, please watch that youtube video. It will help you better understand why it's more useful to discuss the underlying idea than to discuss if we should be using word X or word Y.

[mcphage]

> by someone saying "how do we know this is true", and the answer is, we can't know, therefore we take it on blind faith.

If you're talking about evolution in general, then it makes a large number of predictions about the way things are, that have borne out.

If you're talking about penises scooping out semen, the answer is we can't know, therefore we take it on faith—the answer is we don't know, and so it's one of several hypotheses—none of which are mutually exclusive. Nobody is (or should be, at least) taking it on faith, because nobody should be asserting it as definitely true.

[mannykannot]

It is very telling that you repeatedly use the phrase "blind faith", but you left off the "blind" when presenting definitions.

[mannykannot]

I would be interested to see how you think this short video supports the claim you are making here, as it does not mention evolution, common sense or faith, and is ostensibly about how little knowledge one gains just by learning the name of a thing.

[P5fRxh5kUvp2th]

You don't understand how pointing out the names of things isn't the important property of a thing would be relevant in a discussion with someone who is arguing it should be called X instead of Y?

That's on you, brother.

[mannykannot]

No, the claims made in the video you linked to do not show that, as you put it, "in this case, 'common sense' and 'blind faith' mean the same thing." Nor does your reply to mcphage.

[neonnoodle]

> what if we find out some super advanced alien civilization seeded earth with life and managed it in some way, helping shape things. It would kind of explain a lot

It really wouldn't!

[dsego]

The alien origin hypothesis is just kicking the can down the road.

[P5fRxh5kUvp2th]

how so?

A simple explanation would be that the aliens are much simpler than we are in makeup because it happened purely by evolution, and that part of our complexity came through planning.

There's just too many possibilities to so confidently claim it's kicking the can down the road.

[knome]

Simplicity would be more likely to imply creation than complexity.

Simplicity implies understanding and intent.

No one would design the absolute spaghetti code mess that underlies our existence.

Look at the computers we build. Neat little rows and friendly little abstractions.

Life isn't. It's billions of years of good enough hacks layered one atop the other, and sometimes transitioned sideways from other forks of the code base.

Near half our DNA is just viral cruft that got mixed up and passed along for untold generations.

>Eight percent of our DNA consists of remnants of ancient viruses, and another 40 percent is made up of repetitive strings of genetic letters that is also thought to have a viral origin

https://www.cshl.edu/the-non-human-living-inside-of-you/

[P5fRxh5kUvp2th]

none of that obviates that there could have been a design at some point.

It's just fun to think about.

[dsego]

Suppose living matter came to earth on an asteroid. That still doesn't explain how living things emerge from non-living matter.

> the aliens are much simpler than we are in makeup because it happened purely by evolution, and that part of our complexity came through planning.

That looks like argument from complexity. And it seems that complexity through planning would require an even more complex creator, not a simpler one.

> There's just too many possibilities

I don't think it makes a difference either way. If we can figure out one way of making life from non-living matter, we've cracked the code, we don't need to know how exactly it happened.

[P5fRxh5kUvp2th]

I think you need to read back over what I said and consider that you've _completely_ misunderstood it.

[oezi]

It is assumed that life started by chance events surrounding chemicals which possess attributes of self-replication.

[P5fRxh5kUvp2th]

I'm aware.