Indeed, this criterion has been used extensively in the debate over whether intelligent design qualifies as a scientific concept.
Nope. There's no debate at all. Intelligent design is not science. ID is the opposite of science. No debate about that in scientific circles.
Really, Pressie? Semantic nitpicking is the only thing you have to add to this discussion?
If you will look up the definition of the word "debate," you will find that what I said was wholly correct.
If you carefully read what I wrote, you will also see that I said nothing about there being an ongoing debate over ID in scientific circles. What I said was that the criterion of falsifiability was used in the debate over ID's scientific legitimacy or lack thereof. Both scientific and pseudoscientific discourse doesn't happen in a vacuum; they occur within a social, political, and philosophical context, and debate can very well be found in the fibers of this social-political-philosophical fabric, even if it is not found within the scientific community or in the halls of academia.
Generally speaking, I endeavor to structure my sentences in ways that reveal very particular nuances, so knee-jerk semantic nitpickings might gloss over that. Read carefully and don't assume.
quote: Umm, the theory of universal common descent is a fairly broad model, and it's perfectly falsifiable (Karl Popper argued otherwise, but I don't find his argument particularly compelling). Is it your position, then, that the broader a model is, the less falsifiable it needs to be
The more possibilities encompassed by a model the less falsifiable it will be - in general. And yes, I argue that falsifiability is desirable but not a necessity. When we get down to detailed hypotheses it becomes far more necessary.
quote: 1. It would not require assumptions; the thesis that panspermia offers more time is tied to the available evidence we have that indicates that there was a relatively large number of already habitable planets at the time of Earth's origin about 4.5 Ga.
If you're invoking extra-solar planets then I have to ask how you plausibly get life from there to Earth without making assumptions.
quote: 2. You are correct in stating that panserpmia adds in the extra step of getting biological life from a putative source to Earth. But then again, many subsets of abiogenesis models invoke an extraterrestrial source for life's putative organic precursor molecules. Further, if the origin of life outside of Earth is much more realistic instead of an origin of life within Earth, then this additional step the panspermia model adds is not unnecessary -- and therefore does not make the panspermia model particularly less parsimonious than the RNA world or metabolism first scenarios.
Since panspermia doesn't address abiogenesis I'd suggest that steps in abiogenesis are off the table. You can't say that they are "extra" while just taking abiogenesis somewhere else for granted.
quote: is doesn't address my argument that conjuring all sorts of speculative panspermia models isn't exactly a fair way to test the falsifiability of actually plausible panspermia hypotheses.
OK I'll address that point. It is an obvious red herring and completely irrelevant to my objection.
If you are claiming that panspermia is falsifiable you have to show that - not that there are falsifiable scenarios for panspermia.
quote: Okay. So you don't know how the RNA world model could be definitively falsified.
And you concede that my original point was correct, since you can't say anything against it.
quote: So why is the panspermia hypothesis better at generating evidence of a historical nature in contrast to the RNA world and metabolism first models?
Hypotheses don't generate evidence.
quote: That's not necessarily true, though. There can be a priori biases against investigating panspermia based on conformity to scientific orthodoxy.
Your objection fails to address the point. The issue is not the question of whether the work is done, the issue is whether there is potentially useful work to do. And you seemed to want it both ways - suggesting that there was no useful work to do because there was useful work that had yet to be done.
To return to the point, proposals that are never offered can't be rejected due to bias or any other reason. There's no use saying "spend more" with nothing to spend it on.
Yes. Really. ID is not science. ID is the opposite of science.
With respect, you might want to improve your verbal comprehension skills. My sentence "Really, Pressie?" was linked to my following sentence regarding your semantic nitpicking, not to your claim regarding ID and its non-scientific status.
Doesn't matter how long your word salads are.
Yeah, you're not actually going to address the argument I made dissecting your semantic nitpickings, are you?
Yes, it was. It doesn't matter how many words you use; how many sentences you put in, how many paragraphs you write down; how many essays you publish somewhere; how many books you write; ID still is the opposite of science.
Gentlemen, let's settle down. Discussion boards just naturally amplify minor annoyances, disagreements and misunderstandings. Where else can a simple, "Life is good!" bring responses like, "The world is going to hell in a handbasket, you idiot." I don't know why, but somehow emotion creeps into almost anything said at a discussion board, whether intended or not, and escalation is routine. Strive for clarity and consideration, accept when it isn't achieved, and try again.
I said your post had a number of problems. Here's another.
You say that the lithopanspermia model is falsifiable because if the work of Cavalier-Smith could be shored up and made more rigorous, then lithopanspermia would in fact have been falsified.
But why is that not also true of the RNA world hypothesis and the criticisms of Bernhardt, Kurland, and Harish & Caetano-Anollés? The two cases would seem to be on a par.
After all, if you really think that the RNA world is unfalsifiable, why are you citing these people at all? For the RNA world to be unfalsifiable, these criticisms would not merely have to be wrong, rather they'd have to be either (a) in principle and by their nature undemonstrable or (b) irrelevant even if they were right --- neither of which you have argued for.
Instead, you seem to be in one paragraph citing these people to suggest that the RNA hypothesis is false, and in the next paragraph complaining that it's unfalsifiable. Well, one or the other. If it's unfalsifiable, then you should be able to demonstrate the logical necessity of the complete vacuity of the arguments of Bernhardt, Kurland, and Harish & Caetano-Anollés. If, on the other hand, these arguments are even conceivably valid and relevant, then they bear the same relation to the RNA hypothesis as you say (wrongly, as I have argued) that Cavalier-Smith's work (or an improvement on it) bears to lithopanspermia.
Dr A. beat me to the point I was going to make, but I'll reiterate it in my own words anyway.
To me, the evidence you presented against the RNA World and the evidence you presented against Panspermia are analogous. Remarkably so, in fact.
In grade school, I remember being taught to use this format for analogies:
x:y = a:b
It's read "x is to y as a is to b."
(actually, I think the "=" might have been two colons "::", but it's close enough)
Now, insert the following values for the variables:
x = "RNA is inherently unstable" y = RNA World Hypothesis
a = "basal prokaryotes are vulnerable to cosmic rays" b = Panspermia
To me, this analogy holds perfectly true with these values inserted. The two evidences (x and a) address very similar questions about their respective proposed protobionts, don't they?
They both rely on a reasonable modern surrogate to examine the chemical/physiological shortcomings of their putative biotic progenitors.
Where they differ is in where their explanatory power comes from. I would argue that the phylogenetic falsification of the Panspermia hypothesis has more power from a historical perspective, but less power from a mechanistic perspective, than the biochemical falsification of the RNA World hypothesis.
The core of your argument is that only the historical approach grants the power of Popperian falsification. I would argue that you are just showing a little phylogenetic chauvinism.
No, I'm saying that restricting observations to those relating to a single event is a good way to lose generality. By looking only at particular circumstances you limit your ability to understand what would happen if the circumstances were different.
To take an example, if panspermia were true any abiogenesis work relying on conditions on Earth would be of questionable use - the conditions where life really arose may have been different in relevant ways. Work which looked at the possibilities without considering the history of the planet might be more useful in figuring out abiogenesis.
Yes, speculative models are of considerable value in driving exploratory science further. This is not -- in itself -- a criticism. However, there is much focus in current OOL research on establishing the biochemical plausibility of abiogenesis models, instead of hunting for clues that these models are grounded in historical reality. Contrast this with panspermia, where much of the evidence is of a historical nature rather than a focus on mere plausibility.
I don't see this to be the case from looking at the evidence you've presented for panspermia. Of the four studies you cited in support of panspermia; Rampelotto's you described as overcoming objections, which sounds very much like establishing plausibilty (I haven't read the article) and Mautner's and Melosh's are both explicitly establishing the plausibility of micro-organism's being transported through space.
The fourth, Wallis (2003), I'm a bit surprised that no one else has picked up on yet, as this is a wildly speculative article about the dinosaurs being wiped out by poisonous fungi from space. It's short, and I would highly encourage everyone to read it; including yourself, as I get you impression you may not have based on your relatively complimentary description.
Yes. Really. ID is not science. ID is the opposite of science.
You've said this twice, but what does it even mean to be "the opposite of science"? What does it mean to be the opposite of chemistry, or biology, or physics? This really doesn't communicate anything, except to tell us that you don't like ID.
IMO, ID is philosophy, not science. But there's no way that philosophy is "the opposite of science". Science and philosophy help one another; it is impossible to do science apart from a philosophy of science.
"Science without religion is lame, religion without science is blind." – Albert Einstein
“I am very astonished that the scientific picture of the real world around me is very deficient. It gives us a lot of factual information, puts all of our experience in a magnificently consistent order, but it is ghastly silent about all and sundry that is really near to our heart, that really matters to us. It cannot tell us a word about red and blue, bitter and sweet, physical pain and physical delight; it knows nothing of beautiful and ugly, good or bad, God and eternity. Science sometimes pretends to answer questions in these domains, but the answers are very often so silly that we are not inclined to take them seriously.” – Erwin Schroedinger
... what does it even mean to be "the opposite of science"?
Science is the process of going from data to conclusions. The opposite would be to start with the conclusion and try to find data to confirm it. That's exactly what creationism and its bastard child ID do, the opposite of science.
What does it mean to be the opposite of chemistry, or biology, or physics?
That's an entirely different question. Demolition is the opposite of construction but there's no opposite to a hammer.
Thanks for all of your responses. I appreciate the critical interest this has generated. I've had a busy, caffeine-fueled past couple of days so wasn't able to reply. I'll be getting to this over this weekend though.