In <3oumuk$4ff at agate.berkeley.edu> frauwirt at notmendel.Berkeley.EDU
(Ken Frauwirth (BioKen) writes:
>> 1) Parasitism does not mean death. An organism may well carry a
parasite load and be perfectly able to survive.
>Perhaps not for all parasites, but for many it does mean death,
especially in immunocompromised hosts. And without an immune system,
the parasite load might very well be higher (and fatal).
I agree that this is true for most cases...
>> 2) I do not agree with you that the FUNCTION of immune systems is to
protect an organism from 'undesirables'. I have always been bothered
by this concept, finding no reason at all to beleive that the immune
system 'protects' one from anything.
>>A problem with discussions such as this is that language often
obscures the intended meaning. What I meant is that the end result is
that a (if not the) major advantage of having an immune system over not
having one is that an organism is far less likely to succumb to
infection by pathogens. "Function" implies intent, and I do not
believe that natural selection has conscious intent. Whether or not
the *original* advantage conferred upon the first organisms to have an
immune system was resistance to pathogens, well, that is anyone's
guess. But it seems that the major detrimental effect of destroying
>the immune system (at least in mice and humans) is overwhelming
>susceptibility to infectious diseases (and perhaps cancer).
Yes I agree that the ability 'not to succomb to infections' would be an
advantage. I do not agree that 'Function' implies intent (or purpose
for that matter).
>> 3) I'm not sure that evolution can not be 'directed' under certain
>> circumstances. I think that perhaps many possible machanisms fall
under the broad category of 'evolution' and that some can indeed be
focused.
>Of course it "can" be directed (humans do it all the time - we call it
breeding), but I meant that prior to such interventions (e.g. when the
immune system was evolving), there was no conscious direction involved.
If you had any reproductive advantage over other organisms in your
niche, you outcompeted them. That might mean, "If you are better able
to withstand invasion by infectious organisms, you'll have more
offspring."
I agree (in context I menat that I beleive evolution can be directed).
This might be over-simplified (the immune system is still evolving, and
direct evolution is far from the only selective process) but there
could be some advantage in withstanding invasion.
>An interesting rejoinder, when you state "I don't believe that the
immune system 'uses' any principles... I think that perhaps it simply
exists, time passes, and things are different than they were before."
That is (to me) a very un-Scientific approach. Biology is a very
deterministic science - >everything has a molecular mechanism. Things
don't "just happen", but there is some logic: stimulus/response. If
the immune system simply "changes" with no rhyme or reason, than to
study it is an exercise in futility.
Well, here I think I must disagree with you. One way of looking at
biology is deterministic, but it is not the only way. Things do indeed
'just happen' (unless you chose to mix science with religion...). I
did not mean to imply that a system changes without 'rhyme or reason'
but rather that it changes (acting/acted upon> by possibilitys in what
can happen. This could theoretically be carried far past the level
molecuar mechanisms (perhaps beyond sub-atomics even). However, no
matter how well one can explain something using reductionism, it is
still not going to give you understanding of the big picture.
>> 'What' and 'How' are merely observation...'Why' is philospohy.
>That is exactly my point - it is not Science. Science can only answer
"what" and "how" ("How did the immune system evolve" is not the same
connotation as "Why did the immune system evolve"). I love to discuss
philosophy, but please do not disguise it as science.
>As I stated above, I find it difficult to reconcile these views with a
>Scientific approach. The study of biology (or any science) has the
underlying assumption that life (or physical) processes follow rules,
and that we can work out at least some approximation of those rules,
and that we can then apply those rules to predict phenomena. While I
realize that chaos theoy and particle physics have a degree of
"unpredictability" to them, people who study those fields realize that
the question of "Where exactly is the "electron" is not worth pursuing.
If there is no consistent mechanism by which the immune system is
induced to change (i.e things "just happen"), then its
>study *is* "worthless", at least to Biology (with a capital B).
I think that perhaps you have confused science with technology.
Science is a philosophy (or a way of thinking). It has no concern in
the practicality, marketability, or worth of its acomplishments.
Technology however, is the practical use of laws, rules, widgets and so
forth. A true scientist would never even consider when to stop asking
a question, or how far one should delve into the quest for knowledge,
in much the same way a true technician would never stop to consider a
theory without an obvious practical value. Neither is better or worse
than the other, they are just different. Indeed there are very few who
are merely one of the other. Science seeks to answer 'why' by guiding
technology that answers 'what' and 'how'.
Chris Thoburn
