gmalivuk wrote: J Thomas wrote:
The thing you're missing is that a hypothesis can be rejected without specifically testing for it, and for reasons other than data that explicitly disproves it.
Data that implicitly disproves it is OK too. But you have to be careful now much your theory turns into self-fulfilling prophecy.
This is where occam comes in: the simplest explanation that fits the existing data isn't necessarily the truest one, but it is still to be preferred.
It's OK for you
to prefer whatever you want to. But when scientists reject
hypotheses on esthetic grounds, that's a mistake.
"Aliens left their fossils there" and "dead things left their fossils there" both explain the existence and location of fossils, but this doesn't mean we should try to come up with lots of extra experiments specifically to try and distinguish between these two explanations. We can reject the alien one (at least in the sense of deciding not to spend any time on it) because it requires too many additional assumptions to be the preferred theory.
People used to use fossils to judge the plausibility of evolution. But we've gotten past that now. The evolutionary meme is true by definition. When genes change their frequency in a population, evolution is occurring because that's what evolution is. When a population is in an environment that changes a gene's frequency, the population will evolve because that's what it means for a population to evolve. Given genes that have different fitness in a given environment, the rate of evolution will on average be proportional to the variance in fitness, which itself will tend to be proportional to the variance of the genome. The more variable the genes in the population, the more difference in fitness there will be and the faster the gene frequencies will shift -- resulting in a less-diverse population that can only change slower. In the absence of variance in fitness, populations change by sheer mutation pressure and random loss, plus whatever genetic mechanisms they have available to uncover hidden variability or jigger mutation rates etc.
It's all true by definition, and there is nothing that populations can do that is incompatible with it. It is unfalsifiable because it is not a scientific law but a way to organize our thinking about population changes.
Fossils have a lot of issues. Bony parts tend to reflect an animal's ecological niche. The animals can evolve considerably without changing their bones. And sometimes different climates can result in a degree of morphological change without requiring a genetic change. Paleontologists do their best with what they have. The discovery of fossil DNA will bring some useful improvements on all that, in some cases.
Fossils are a historical thing, like most of geology. Historical questions are in general harder to answer. Like, political scientist could consider the questions, who is likely to think he benefits if a US president is assassinated. Who is likely to actually carry it out? Who in fact does benefit? These sorts of questions can have abstract answers that might tend to fit particular groups at particular time, and over a very long time the validity could be tested. But the question "Was Warren Harding murdered?" is very different. He could be dug up and tested by toxicologists etc, but political scientists might not have a lot of useful data about it.
You can use evolutionary theory to make up JustSo stories about fossils. It can organize your thinking in pleasant ways. You can come up with stories that seem to you to be far better than any competing stories. There isn't going to be a lot of definitive validation.
So OK, fundamentalist Christians can say that the universe was created 6000 years ago with all the fossils in it, that the Devil put the fossils there to deceive people and test their faith. That's a natural argument to make because they study the claims from 1800 years ago that the Devil started previous religions whose god was born of a virgin at the winter solstice and died and was reborn at the spring equinox to redeem the sins of mankind, and the Devil did that to deceive people and test their faith -- he knew how to do it because the Devil can do time-travel or maybe is independent of time like God is. The Devil isn't an additional assumption for them, they've already assumed him. But since the Devil can do anything he wants, this theory is no falsifiable. Christians can use it to organize their thinking.
About aliens, Fred Hoyle proposed a theory of panspermia. He thought life on earth came from elsewhere. That could be. It looks like we got prokaryotes living on earth soon after there was liquid water here. But if you look at the genetic code, it looks like a gray code which was likely evolved. And the details of the code suggest our 20-amino-acid 3-base code may have developed out of a 15-amino-acid 2-base code. And before we even made proteins, we perhaps had life that was based mostly on nucleic acids. RNA can make enzymes, though not as flexibly as protein, and some of our central constructs, for example the structures that read RNA to make proteins, are largely made of RNA that has a lot of little protein modifications. People want to believe that we have had billions of years of prokaryotes with proteins, leaving very little time to evolve everything out of nucleic acids, build a 2-base code, convert it to a 3-base code, and then have a very long time with prokaryotes evolving furiously without much multicellular result. Then suddenly we got eukaryotes and multicellular eukaryotes and here we are. It's plausible that eukaryotes were around for a long time before they showed up in the fossil record, and maybe they were trying out multicellular models for a long time before those got into the fossil record too. But it's possible Hoyle might be right, and prokaryotes might have arrived here soon after they could survive, and perhaps eukaryotes arrived separately. It's a historical question. Possibly we might find some sort of life in comets or something, which might tend to support it.
It isn't really important which theory we believe about the origin of life. There isn't enough data to fill in many details, and what data there is leads to a lot of guesswork. When the evidence is thin, why choose? Maybe aliens brought life here, and then eukaryotic life. Maybe in a reasonably short time we ourselves could design a sort of spore that had a chance to survive a 10,000 year journey to alpha centauri and possibly colonize something when it arrived. Is there something like that already growing here, that very occasionally gets blown into the upper stratosphere and then all the way out? I don't know. Probably a few things.
Lots of things are like that. People are making elaborate theories about the history of the universe based on what must have happened according to the laws of physics, when the laws of physics are not well understood yet. Maybe a bit premature. But it's kind of encouraging that they can come up with something that kind of hangs together, assuming the laws of physics have changed according to a pattern.
OK, so you aren't an engineer. My next guess is something in the humanities.
The Law of Fives is true. I see it everywhere I look for it.