I still don't understand the tears...

Bill Burnett (bbur@wpo.nerc.ac.uk)
Thu, 19 Oct 1995 14:18:19


I wrote:

>>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. :-)

And you (I must admit to weeping quietly at this stage) replied:

>I apologise profusely for misquoting you. If beavers only cry because of
>arsenic and not for emotional reasons this strengthens the AAT case.

You did it again in the same breath (aspirin, arsenic, hey what's the diff?),
but I don't really care. What bothers me is that you somehow think this
strengthens the AAT.
HOW? How how how how how how how how???????????

But anyway...

Point 1. Many terrestrial animals secrete tears to protect the eye. Ergo
there is a good reason for tears. Accepted by you, no emotion involved.
The beasties that went down to the beach and eventually swam away to be seals,
turtles, birds etc. already had tears before they went.

Point 2. These groups are secondarily marine. They do not share a unique
marine ancestor, they are not a clade or a monophyletic group. Even the
marine mammals are polyphyletic. Ergo, tears which you claim are shed under
stress by these groups are homoplastic, they evolved more than once.


1) If, as you claim, 'phychic tears' (horrible term) are shed by all
these marine animals and are a secondary (derived) function of tears that
arose separately on a number of occasions, then why is the marine setting
necessary????? An excretory function (your original argument)
is demonstrably unecessary (above).

In fact, you could even argue that to go from isotonic tears for eye
protection to isotonic tears as an emotional display is more parsimonious
(and, according to some peoples thinking more probable) than to go from
hypertonic excretory tears to isotonic emotional ones.

With regard to emotional tears having a different chemical composition, well,
that's as maybe, they still come from the same gland and they're still mostly
salts and water. As they're isotonic then presumably they reflect what's
flying around the system, which will vary with emotional state. I fail to see
how this affects the argument, but I'm open to enlightenment.

*time for a quick personal observation of crying seals*

Incidentally, baby seals, often anecdotally portrayed as 'crying' by
photographs in heart rending anti-fur campaigns, look just as teary eyed and
appealing regardless of whether or not they're being clubbed to death at the
time. (Disclaimer yes i think it's barbaric.)