RE: Evolution of Man
Not sure how to read that diagram to be honest. It seems very vague to me.
If I read it right it shows the earliest definite fossils of particular groups. Some of those groups probably do postdate the K/T extinction event and others may postdate the Permian extinction. They may have existed before either, but as a far smaller part of the record, so far unrecognised or misidentified. So far as I can see, the diagram just says that the earliest representative fossils of certain groups can be tracked to the Cambrian and that others have not been yet. That's not saying anything about when they first came to exist. If anything it's saying that we find some critters early (because they are common and other things ain't) and some later because they are well preserved due to being younger. Which is hardly earth shattering.
Phyla are created by biologists and palaeontologists, not by nature. They are human classificatory divisions.
Nature evolves at the individual level. New species are created whenever two varietal populations grow distinct enough to merit the name.
New phyla occur mostly when two schools of thought decide that several beasts previously thought to be related, are not. Let's not confuse palaeontology with evolution.
I have already said that we don't know how life originated. Maybe it was a series of extremely improbable events that happened only once. Maybe it was common and happened repeatedly through the Precambrian. Maybe it happened dozens of times and was snuffed by the repeated asteroid bombardment around 2.8Ga ago. Who knows? The fact is the world certainly was different then in at least one obvious respect- It was not teeming with life. Life evolves within a sea of other life. Whatever the earliest "living" molecules were, they wouldn't stand a chance now. And we would be unlikely to recognise them anyway. Maybe they HAVE been created in the lab and we're too thick too realise.
Elan vital as a concept is one I find rather disappointing. It's a sky hook. A magic wand. The fairies did it and ran away. It might be right, but yech! How dull. I'd ask for my money back.
I think we should exhaust the chemical avenues before we go that way. We know DNA is the (all but) universal replicator. We know RNA is required for DNA to operate. We know there are problems with that.
But we've only been looking seriously at this for fifty years. There's a stack we don't know about the chemistry yet.
RE: Evolution of Man
This is unlikely to impress Sam, but I'll explain how I form my attitude towards these things wherein "science knows" we are told. This applies to how I tend to see many branches of the hard or hard-ish sciences -
I take a bird's eye or long-term view of that whole branch of science, bearing Thomas Kuhn and paradigm shifts in mind, as well as changes of opinion which may not be paradigm shifts but which are still very large changes of mind, or new data that causes upheavals within the field.
We can generalise this, and it can be used for a number of sciences. Let's say there have been, for the sake of argument, four true and obvious paradigm shifts in the last few centuries, which usually is the case in the sciences. And a number of lesser but still large shifts. The whole point about paradigms of course is that while each earlier one has been disproved, and while the latest one is accepted and 'believed', all the previous paradigms were accepted and believed to be the truth in their day also - usually quite dogmatically that this was 'the final and whole truth'.
Taking the birds' eye view, it seems quite illogical to settle for any present paradigm in any science as being 'true' even though it may appear to our limited senses to be the 'truth' at this time. It requires a different mind-set, but with it you can escape the paradigms and realise that this is a continuous feature, the shifts, and all present truth claims are very highly likely to go the way of their predecessors. To think that we NOW know 'the truth' is to be caught in the short-sightedness of being the worm in comparison to the more expansive and detached bird's eye view of events over time. Past beliefs have given way to present ones which shall get shoved aside by future ones.
Therefore the way scientists and their followers, in every decade, century and age, have said about new ideas and findings, "Preposterous! Ridiculous! This is impossible!" is in fact repetitiouus old hat. But always with us.
These are general comments by me, but to cast a glance Sam's way ;), I see it happening there, and you may need to eat these words: "Elan vital as a concept is one I find rather disappointing. It's a sky hook. A magic wand. The fairies did it and ran away." The style of ridicule is not new, but also hardly helpful in scientific debate! Have your knife and fork handy. 😀
Edited for typos.
RE: Evolution of Man
Conspiritualist, I missed your last post here till now. An amazing link! I find it hard to see how anyone could doubt from all that, that ancient India had an extremely advanced science and civilisation, with a science in some ways surpassing our. A hundred quotes are possible, but two almost at random would be:
" The atomic energy fissions the ninety-nine elements, covering its path by the bombardments of neutrons without let or hindrance. Desirous of stalking the head, ie. The chief part of the swift power, hidden in the mass of molecular adjustments of the elements, this atomic energy approaches it in the very act of fissioning it by the above-noted bombardment. Herein, verily the scientists know the similar hidden striking force of the rays of the sun working in the orbit of the moon." (Atharva-veda 20.41.1-3).
"The so-called ‘Rama Empire’ of Northern India and Pakistan developed at least fifteen thousand years ago on the Indian sub-continent and was a nation of many large, sophisticated cities, many of which are still to be found in the deserts of Pakistan, northern, and western India. Rama...was ruled by ‘enlightened Priest-Kings’ who governed the cities. The seven greatest capital cities of Rama were known in classical Hindu texts as ‘The Seven Rishi Cities’. According to ancient Indian texts, the people had flying machines which were called ‘vimanas’. The ancient Indian epic describes a vimana as a double- deck, circular aircraft with portholes and a dome, much as we would imagine a flying saucer. It flew with the "speed of the wind" and gave forth a ‘melodious sound’. There were at least four different types of vimanas; some saucer shaped, others like long cylinders (‘cigar shaped airships’)."
RE: Evolution of Man
David- The key question about changes of mind (however we label them) is this:-
Is the new model a refinement of the old, or does it actually contradict the old?
Newtonian mechanics is not disproved by relativity. Classical mechanics is still as correct as it was in 1680. We now have a theory that corrects for the limiting errors at the end dealing with the very big and very fast. QM is doing a similar job in the region of the small. But the core of classical mechanics has not gone away. You can still drive your car according to the laws Sir Isaac wrote.
The process is cumulative. Yes, some ideas are wrong and are whittled away. Phlogiston. The aether.
What I do not see in science is any sign of a turning away from the force / particle / mechanistic view of reality to a spiritual one. I don't actually see how science could make such a shift and remain science.
Of course the conclusions will go on changing- but within limits.
RE: Evolution of Man
Hi Sam,
You are quite right in the examples you cite. Usually we live life instinctively within Newtonian mechanics. If we drop-kick a ball upfield I have a pretty good idea where it will come down in terms of our working model knowledge of speed, air resistance and gravity - and don't bother with quantum mechanics!
Not only that, but I must go back and re-read Kuhn sometime. I was pulled up a while back on a forum as there's more to his model of paradigms than I recall or than most people now talk about.
However the bottom line is that there are complete changes, even almost reversals, of what is the accepted normative belief within some fields of knowledge. The world is flat of course - then in time, no, it isn't, it's round (no it isn't, it's actually slightly pear-shaped!); meteorites come from lightning - but then later they come from space; big cats living wild in Britain is a fantasy - then no it isn't, it's a fact and the police make a token effort to go out armed to protect livestock and people; etc. It isn't so long since the Christian West believed the world began 3-4,000 BC.
I recommend the way of handling this phenomenon of ongoing change by accepting that in cases such as you cite the process will certainly continue - Newtonian physics will remain fine for many uses perhaps, but there are even more refinements to come. (Yet who can say there won't be a complete paradigm shift,as we won't know till it happens? Many are researching what is broadly called the Night Side of Nature.) But to the point of this thread in particular, where the goalposts have been continually moved, such as ideas and statements about where or when humanity began, the one consistent fact there is that the dates keep changing. Isn't it sheer logic then not to accept that any present ideas or dates will hold for long over time?
The times, they are a' changin'! 😀
Venetian