Definitions

The problem with words is that they are almost as slippery as the concepts that they purport to represent. I've already made one try at showing how different perceptions of a word's meaning can lead to problems. Here is another.
Let's start with an easy one - LIFE, and the associated word ALIVE. If I say that something is alive, what do I mean by it? Can we say that a rock is alive? Why not? What about a prion? A virus? An amoeba? A politician?

The classical biologist would say that something is alive if it is a self-contained organism that ingests food, excretes waste, and reproduces [1, 2]. This, rocks are not alive, as they do not reproduce, whereas amoebas and politicians are alive as they eat, exrete, and reproduce. But what about the other two?

That is where things get interesting. When they were first discovered, viruses were not considered to be alive in the classical sense as they neither eat nor excrete. All they do is reproduce [3]. A virus will infect a cell and self-destruct as it hijacks the cell's own systems to make more little viruses. No eating, no excreting. But today, most biologists will agree that a virus is "alive".

Prions are even more primitive than viruses, which at least have chemical shells covering the load of DNA in their core. All a prion is, is a twisted protein that coerces other proteins to twist like it. Prions are responsible for some pretty horrible diseases, from kuru to vCJD (aka "mad cow disease"). Many biologists are pushing for them to be recognized as perhaps the most primitive form of life possible and our ultimate ancestor [4].

Related to the definition of life is the associated concepts of "viability" and "non-anthropogenic". "Viable" organisms are those that can survive in their original environment. Thus gametes are not viable prior to syngamy - after which, they are no longer gametes. But what about the things that transport those gametes? Consider the humble octopus. When the male octopus feels the stirrings of spring, it grows an appendage that holds its load of sperm. The appendage then detaches and swims off into the dark, never to be seen again; the male in many species dies after this. Using primitive chemosensors, it will track down nearby female octopuses and bump up against them until she gets iritated enough to tear it apart. Is the appendage alive? Is it viable?

"Non-anthropogenic" is an even more interesting term, as it is in the list only as a hold-over from the early days of the field when the idea that we could build an organism (even one as simple as a prion, a virus, or a bacterium) was the stuff of science fiction. Today, it is the stuff of reality.

Biology is rife with such words [5]. If you want to while away an evening, try to define species in such a way that there are no loopholes such as ligers, ring-species, or cladistic anomalies.

The situation is actually worse when it comes to more personal fields. For example, what constitutes a "Christian"? Is believing in the reality of a person known as Jesus Christ enough? Or must one agree also that he was the Son of God/God incarnate? Must one further agree that only those books agreed upon at the Council of Nicea describe his life? Or can one include Apocrypha or the Book of Mormon? Can one be one's own priest? Or must one hold to a heirarchy? If so, which one? Is the intent of the Host purely metaphysical (implying that any bread will do, provided that it is properly blessed) or does it requite a rite by rote (implying that folks who use the wrong type of bread should go to Hell for their lapse)?

And then there's politics. If one agrees with every plank of the Republican platform except a balanced budget [6], can one be a "true" Republican? If one agrees with every plank in the Democratic platform but does not agree to swear to "fully support" the party's ultimate candidate for president without knowing who that will be, is one a "true" Democrat [7]? By these rules, was Teddy Roosevelt a true Republican or a true Bull Mooser?

The fundamental problem is that "Man is not a rational animal. He is a rationalizing animal." and that carries over into discussions and arguments. We will hold that a person cannot be a "true" <FITB> because they do not follow all of the tenents of <FITB> - and then forgive some other schlep for not doing so [8]. We allow our positions to decide our facts, instead of the other way around. As a result, we get extremists of every stripe throwing invective as if it were argument and a darn site more heat than light [9].

Fortunately, on this blog, such has not been the case [10]. And I would like to thank all of you for making it so.

John

[1] That last is taken as applying to the organism as a species, not as an individual. Thus, castratos are alive even if they do not, personally, reproduce.
[2] Throghout this (and, indeed, all of my blog discussions), we will ignore the unprovable question of "animus" or "spirit". To an animist, such as the Ainu of Japan, the rocks are alive in that they have an animating spirit.
[3] Which my virus friends tell me isn't nearly as much fun as it sounds like.
[4] I.e., the first self-replicating molecules to arise from the abiogenic, chemical-rich soup of early Earth.
[5] As, indeed, are all fields of human endeavor, from geology to religion.
[6] In other words, is honest about his intent to spend more than the government takes in.
[7] On this one matter, at least, Kucinich is acting like a statesman and not like a politician.
[8] Or, indeed, call him a "saint".
[9] Witness the incident with Romney and the reporter. The reporter had the facts on his side, and yet Romney is casting himself as the victim and trying to get the reporter blackballed for doing his job of reporting the facts.
[10] So far. <crossing fingers>