What is "Earth-like"?

[pErvinalia]

It was rainbow's claim that evolution of existing life forms would be necessary for them to eat any new life forms. Can you not read?

Better than you, obviously.

How is it obvious? You seem to have no fucking clue who said what in this thread.

[Forty Two]

Dude - this is painful. You are painful. And what's worse, I think you even think you're correct here. I think you honestly believe you are in the right, even though you are just absolutely off course. The only way you could be this wrong, and think you're this right is if you never read a book on Logic or Probability and Statistics.

Here is an obvious example. Your neighbor maintains that he keeps a pet elephant in his garage. It's alleged to be a perfectly normal visible large grey elephant, of average elephant size, and normal elephant biological functioning. You go to look and you cannot see any elephant. You enter the garage, which is quite small, and look around it. There is no elephant smell or any elephant droppings. In fact there is a total lack of evidence of any sort which would suggest there is an elephant in the garage. You would quite reasonably assume that the absence of elephantine evidence indicated the absence of the elephant.

The absence of evidence is EVIDENCE of absence. Whether it's strong or weak evidence depends on how likely it is that an event would produce the evidence.

Or, you hear some rustling noises in your backyard, and you want to figure out if the noises were caused by your neighbor's dog or by some other intruder. Fortunately, you know what your neighbor's dog is like — he's rambunctious and he barks constantly. So you listen closely, and after 20 minutes you don't hear any barking. What should you conclude? If you had heard a barking noise, that would have been evidence for the neighbor's dog being there. Thus, the absence of barking is at least "evidence" that the noises were caused by something other than the dog. Even though your neighbor's dog might still be the most probable cause of the noise, the absence of barking is evidence of absence of your neighbor's dog.

Here - this is a fine explanation using conditional probability to lay out the logic for you -- http://oyhus.no/AbsenceOfEvidence.html and another way to explain it is here: http://lesswrong.com/lw/ih/absence_of_e ... f_absence/

People quite often state wrongly that "Absence of evidence is NOT evidence of absence." Why do they do that? Perhaps because they do not know better? And with this proof they get the possibility of knowing for sure that "Absence of evidence IS evidence of absence.", which is quite useful in many situations, such as these:

Absence of evidence for...
...fairies, trolls, and ghosts...
...weapons of mass destruction in Iraq...
...crop circle aliens...
...gods...
...Microsoft patents in Linux...
...miracle healings...
...credentials...
...CO2 from machines causing global warming...
...UFO space ships...
...telepaty, ESP, and telekinesis...
...Linux stealing code from SCO corporation...

...means they get less likely all the time.

Absence of evidence damn well IS evidence of absence. For fucks sake, man.

[pErvinalia]

It's simply not, unless you are talking on a scale that means it is physically possible to investigate all space and definitively prove that the absence of evidence is evidence of absence. This is fucking simple stuff. You show repeatedly you can't even grasp the basics of logic and arguments. It's a level of Dunning-Kruger that is embarrassing.

[pErvinalia]

Ok, I just looked at your link, and it's an argument from semantics. I am clearly using the phrase in the second meaning described in the link, although, the correct way to state it is: "Absence of evidence is not proof of absence".

[Forty Two]

It's simply not, unless you are talking on a scale that means it is physically possible to investigate all space and definitively prove that the absence of evidence is evidence of absence. This is fucking simple stuff. You show repeatedly you can't even grasp the basics of logic and arguments. It's a level of Dunning-Kruger that is embarrassing.

Of course, you just skipped over the proofs and examples.... you're that pigeon playing chess who knocks over the pieces, craps on the board, and then struts around as if he's won...

Why in the fucking world would we need to "investigate all space and definitively prove" something for the absence of evidence to be evidence of absence? Are you high? Having "evidence" for something or against something doesn't mean it's been definitively proved.

Absence of evidence does not "definitively prove" absence, numbnuts. It's EVIDENCE OF absence.

[pErvinalia]

This is semantic idiocy. Read my next post. I clearly mean proof of absence. Although, no doubt you will deny this. Black is white, after all...

[Forty Two]

Ok, I just looked at your link, and it's an argument from semantics. I am clearly using the phrase in the second meaning described in the link, although, the correct way to state it is: "Absence of evidence is not proof of absence".

I've previously pointed this out -- for example when I said "A better phrasing is "absence of evidence is not conclusive proof of absence." But, that doesn't sound as catchy." You then continued your nonsense.

"argument from semantics" -- lol -

[JimC]

"Tigers don't eat trees" is a poor analogy to oppose an argument that any new replicators would most likely be quickly devoured by the existing biota. New replicators would not be organised cells, they would be some form of large, self-assembling carbon-based molecule. In the conditions of the early Earth, any such replicators would have an abundance of smaller molecules around them to assist their early, inefficient means of replication. Not so in the current world.
Even if the new replicators are chemically different to the various nucleotides and proteins in current life, the abundant bacteria that would confront them are massively diverse, with an astonishing array of metabolic pathways available. One or other will certainly have some chemical pathway which will metabolise any new variant of carbon chemistry. The replicators themselves are defenceless - they would disappear quickly.
And of course, carnivores like tigers can digest and make use of some plant material - it is not a deep-seated chemical incompatibility, but simply an evolutionary niche that is optimised for the rapid digestion of flesh. Plenty of omnivores, ourselves included, can make use of virtually the whole gamut of living organisms. Bacteria, however, can metabolise an extremely wide range of molecules, including quite a few novel chemicals synthesised by man.
To sum up, I do not think it likely that there are enough suitable environments in the current world where early replicators could form, and in the unlikely event that they did, their "lives" would be cut short quickly by the ravenous hordes of ubiquitous microbial life.

[pErvinalia]

Ok, I just looked at your link, and it's an argument from semantics. I am clearly using the phrase in the second meaning described in the link, although, the correct way to state it is: "Absence of evidence is not proof of absence".

I've previously pointed this out -- for example when I said "A better phrasing is "absence of evidence is not conclusive proof of absence." But, that doesn't sound as catchy." You then continued your nonsense.

"argument from semantics" -- lol -

Of course it is an argument from semantics. I clearly used it in the sense of proof. And it is logically sound with that usage.

[rainbow]

Exactly. And that's why I mentioned it in reference to rainbow's extraordinary claim. You seem to be confused, like 42, that i've made a claim about the likelihood of abiogenesis.

I did not make any "extraordinary claim".
Please stop making this false assertion.

I pointed out in very simple terms why it is unlikely that new life would be eaten by existing life forms. I can only assume that you failed to understand what is basic science and logic. Based on this, there is really no point in engaging you in any further discussion on this topic. Why 42 bothers when you've been so clearly bested, I've no idea.
...but seriously dude, I suggest you stop before you make an even bigger fool of yourself.

[rainbow]

"Tigers don't eat trees" is a poor analogy to oppose an argument that any new replicators would most likely be quickly devoured by the existing biota.

No it is spot on. Life has evolve to fill niches. Different forms of life coexist. The evidence is all around.

New replicators would not be organised cells, they would be some form of large, self-assembling carbon-based molecule.

Do you have any evidence to support this?

In the conditions of the early Earth, any such replicators would have an abundance of smaller molecules around them to assist their early, inefficient means of replication.

Please reference scientific papers that support this statement.

Not so in the current world.

There are plenty of smaller molecules around today, and there are probably more since photosynthesis started.
...and even more since man-made organic chemicals started entering the environment.

Even if the new replicators are chemically different to the various nucleotides and proteins in current life, the abundant bacteria that would confront them are massively diverse, with an astonishing array of metabolic pathways available.

It might be astonishing to you, but they can not digest everything. I explained this to you when discussing biodegradability. They can not even digest mirror images of amino acids that they themselves are made of. Do you understand stereochemistry?

One or other will certainly have some chemical pathway which will metabolise any new variant of carbon chemistry.

Evidence?

The replicators themselves are defenceless - they would disappear quickly.

Can you support this statement with anything even vaguely scientific? What did these replicators look like, and which environment did they occupy?

[JimC]

The key evidence is that there have been no new replicators!

We won!

[pErvinalia]

Exactly. And that's why I mentioned it in reference to rainbow's extraordinary claim. You seem to be confused, like 42, that i've made a claim about the likelihood of abiogenesis.

I did not make any "extraordinary claim".
Please stop making this false assertion.

I pointed out in very simple terms why it is unlikely that new life would be eaten by existing life forms. I can only assume that you failed to understand what is basic science and logic. Based on this, there is really no point in engaging you in any further discussion on this topic. Why 42 bothers when you've been so clearly bested, I've no idea.
...but seriously dude, I suggest you stop before you make an even bigger fool of yourself.

You're siding with 42. Who's more likely to be the fool?

To add to the foolishness, you are attempting to rewrite history. I'm not talking about an alleged claim that it's unlikely that new life would be eaten by existing life forms. I'm addressing your claim that new life would be unlikely to occur in today's conditions. As I said in my initial response to you, we don't even know how our current system of life emerged, so it's an extraordinary claim to virtually rule out other forms of life from arising.

[Forty Two]

This is semantic idiocy. Read my next post. I clearly mean proof of absence. Although, no doubt you will deny this. Black is white, after all...

Yes, you say you meant to write something different than you wrote, even after I identified exactly that difference, and you claim that it is I who says black is white.

To recap -- I explained why absence of evidence is, in fact, evidence of absence. I even explained to you that a better phrasing would be absence of evidence is not conclusive proof of absence.

You blather on about how I don't even know how to logic, and that it's so simple that absence of evidence is not evidence of absence. I explain to you more than once, in words a three year old would understand, and you keep on with your nonsense.

Eventually you decide you've been shown the light and you decide, oh, I can't just admit that absence of evidence does, in fact, constitute evidence of absence, at least sometimes -- you instead decide to say that what you "clearly mean" is "proof" of absence. Of course I will "deny" this. It's not what you said. And, it's what I told you some posts ago, and you still continued on with your original position.

Further, you're still off a bit if you say "absence of evidence is not proof of absence." What evidence of absence is not is CONCLUSIVE proof of absence.

Nevertheless, as you have now acknowledged that absence of evidence is, in fact, evidence of absence, then our debate on this topic is closed. This whole "black is white" accusation you keep making against me is laid bare, however, by the fact that you attempt to level this allegation at me, at the same time as you are declare that you meant something other than what you wrote. You didn't just write it once, dude. You were on about this for days. And, you kept on about it even after I laid it out for you on a silver platter - telling you that "proof" was the better word to use (albeit with the modifier, conclusive).

[Forty Two]

Ok, I just looked at your link, and it's an argument from semantics. I am clearly using the phrase in the second meaning described in the link, although, the correct way to state it is: "Absence of evidence is not proof of absence".

I've previously pointed this out -- for example when I said "A better phrasing is "absence of evidence is not conclusive proof of absence." But, that doesn't sound as catchy." You then continued your nonsense.

"argument from semantics" -- lol -

Of course it is an argument from semantics. I clearly used it in the sense of proof. And it is logically sound with that usage.

If you "clearly used it in the sense of proof" why did you continue to maintain your position after I illustrated the difference between evidence and proof?

Stop it, eRvin. You're embarrassing yourself.