River of Tears (long and boring to most)

Bill Burnett (bbur@wpo.nerc.ac.uk)
Wed, 18 Oct 1995 17:32:48

In spite of my intense dislike of this kind of post I've been forced (by my
unreasonable ego) to produce one.

If you're not James Borrett (who won't let me email it to him) I apologise for
it's potential unreadability.

Concerning why tears are a poor salt excretion mechanism I wrote:

>>Yes, well, so they do. On the other hand, if you want to REDUCE internal salt
>>levels then you need to INCREASE the concentration of your excretion product.

And you (James) replied:

>Well I would definitely like to know if our ancestors had saltier tears
>than us. It's a hypothesis that I would like to put forward that they
>did, but unfortunately I can't think of anyway to test it. If anyone can
>I'd be delighted. As far as I know only marine animals, humans, elephants
>and beavers cry when emotionally disturbed.

How do you know beavers cry when disturbed? I brought the beavers up in the
first place, and I certainly never said they cry.

Then I said...

> You can't
>>afford to waste water in a salty environment or you get dehydrated very

To which you reasonably reasonably replied...

>You equally can't afford to do this in the savannah mosaic.
- -deletion being careful to maintain context- -
> But I do admit that getting drinking water in a
>marine environment would have been a big problem.

and I am forced to concede that of course the savannah mosaic is in trouble
here too, if the assumption that tears are for salt excretion is true... Which
I don't think it is. My position might conceivable be weakened, except that
you know I don't necessarily advocate the SM so setting it up as a straw man
is even more pointless than usual...

I'm not using the AAT as a straw man because I'm not trying to show the SM is
correct, only that the AAT is fallacious. Or more precisely, I'm trying to
argue against assumptions it depends upon which I consider unreasonable on the
basis of my experience of marine and evolutionary biology (I call myself a
marine evolutionary biologist and like to labour under the impression that I
know more than nothing, if less than many).

Then you said...

>beavers cry to flush out arsenic from tree-bark in their diet, so there
>are probably others....

Back to beavers. I said aspirin. If you have another source I'd be
fascinated but if you're citing me against me at least cite me correctly. :-)

A bit later on I suggested (in slightly flippant vein) that:

> all those mammals which don't have dry corneas have
>tear ducts of some description, or am I wrong?

>Yes, but in most terrestrial mammals (ie all besides humans and
>elephants) tears are only shed in response to chemical irritants or grit
>in the eye. Emotional tears in humans are biochemically different too.

Okay... to recap on the argument from our posts so far...

I strongly stated that I thought the emotion thing was BS.
You countered that you thought tears evolved as an excretory mechanism
and then became a display or consequence of emotion later on.

Right... tell me this. If terrestrial mammals produce tears for any reason,
and furthermore for a very sensible reason i.e. maintenance of a functional
eye why can't crying in response to emotion develop in them just as you claim
it has in various unrelated marine groups?

Okay... I erect the hypothesis that it did. Prove me wrong.
Ouch, I cringe from my own childish unscientific stance... except it's the
same as yours.

Then briefly back to elephants:

>Or you could convince me that elephants don't have a marine ancestor.

Or you could convince me that they did. I'm looking, so far the only ref.
I've been able to locate either way shows the elephant and sirenian middle ear
to be homoplastic and weakens your assertion. This ref will, I hope, be a
source of more interesting ones arguing either way and will provide some of
the meat missing from both of our arguments.

>Do I really sound like a crackpot scientific creationist?

Only when your arguments rest on faith alone.