[edit: sorry that the following is unresponsive to the last page of posts. It takes me too long to compose these things and you guys type too fast}
Lewis Thomas has a great quote that I used to have in a little frame on my desk:
"A 'fact' is simply the point at which investigation has ceased."
I don't like to use the word 'fact' in conjunction with the word 'science.' We do not assemble facts. We assemble observations.
Observations can be mistaken, hence the importance of reliability measures and replication studies.
Observations can be biased. Observations can be irrelevant to the question at hand.
It is difficult to explain to the lay person the hesitancy with which scientific explanations are advanced. "Facts" and "certainty" are not really part of our vocabulary.
Sidonzo: I agree with hal. I don't think either Intellligent Design or the Theory of Evolution (where it concerns the origin of life) can be taught as science. Micro-evolution IS science. It is something that is observed right now and can be tested right now, but no scientist has ever seen macro-evolution (evolution from one kind of animal to another) happen because it takes millions of years to happen.
As I stated above, it does not always take millions of years to happen. Speciation means that the organism changes in such a way that it can no longer produce fertile offspring by breeding with its ancestral genotype. This definition does not change with the length of time involved. The distinction that you make between macro and micro evolution is not a distinction that would be made by an evolutionary biologist.
Onizuka: Ice Age comes. Who survives? The really clever, the really furry, and the really big.
You've touched on a really good point, Onizuka, which is that "well-adapted" means well-adapted to a specific environment. There is no such thing as fitness in general. There is only fitness for certain conditions. We have no idea what human traits will prove most valuable during the next Ice Age. There is no way to predict what kind of changes might visit our species tomorrow.
Hal: I CAN'T bury an animal for ten thousand years and see what the bones look like compared to what will exist in ten thousand years, or compare it to what existed a ten thousand years ago. It's just not possible.
OK, let me give you the three methods Darwin proposed as acceptable for evaluating events in the different past:
1. observe small events happening now, and extrapolate the effect of these events if they happened over eons. For example, the role of earthworms and ants in creating topsoil.
2. observe current events that appear to be different stages of the same process. For example, the formation of coral reefs
3. look for anomalies that reveal historical descent. These are often found in the reproductive organs of plants and animals - small differences result in new species because they physically inhibit interbreeding. For example, in the Hawaiian islands there are 27 different species of grasshopper that differ only in the minutae of the genitalia.
Interpretation of the past events has to rest upon something that is observable in the present.
Evolution from nothing is a perfectly valid guess for the origin of mankind ...
First of all, no one says that humans evolved from nothing. What does that even mean?
Second, scientists don't just "guess." I don't know why the choice is always between these two things: certainty, or a guess. An hypothesis is neither of these things. It's a proposition that can be tested in a particular way.
And I'm sorry if conversations about evolution so often devolve (no pun intended) into assignations of character to one side or the other. I think one can ask quite seriously how likely it is that the spiritual life of humans is a product of physical evolution. I don't know the answer to the question, and luckily neither my discipline nor my religion require me to ask it.
But I think that non-scientists have a rather naive view of what is required of scientists to be legitimate within their fields. It's not like working in a grocery store, you know. And it's rather insulting to have our work referred to as "a guess" considering that it takes decades of higher education to be able to do this kind of work. Scientists spend more years in school than doctors or lawyers do, though doctors are catching up to us because so much of what they do these days requires scientific training.
I just finished ... well, finished for the moment ... a model I've been working on for ten years. Ten years! - to answer one stupid question, and it's not even an important question. Well, I thought it was important, but it's not going to win me the Nobel Prize or change the whole field of economics. By the time my career is finished, I'll have answered two questions. Maybe. If I get to keep working for another ten years.
Ten years ago I was guessing that this model could be built. Now that I feel ready to put this out for publication, I'm no longer guessing. So it would be very irritating to walk into a City Council meeting and be confronted by a grocery clerk who'd read one book about economics and be told that in his opinion my guess is all wrong. Likely I would hand him his ass on a platter, as SF said in another thread.
Jn