The most recent exchange about the extraterrestrial life made me think of this monologue of Richard Feynman,
especially its last minute. Why? Because it seems to me that some people are so frightened not knowing things that they prefer quickly chosen wrong answers over the admission that they're ignorant or uncertain.
In these sentences (taken from The Pleasure of Finding Things Out, BBC/NOVA, 1981), Feynman said that some people are searching for answers to deep questions that science can't answer or basically labels as unphysical, so they may get disappointed and turn to religion and other mystical world views instead.
He also describes the Copernican principle – the existing religions seem too provincial, too connecting the fundamental entities of the Creation with our particular stinky pond here on Earth, our DNA etc. These links seem totally out of proportion.
In the final portion, Feynman said that it was important not to predecide what sort of answers we should be getting. The plan of science should ultimately be as general as "the plan to find more things about it". At every moment, a scientist like him unavoidably has different levels of knowledge, certainty, or ignorance about different things. It didn't frighten him not to know about the purpose of the being – and many other things.
When I heard or read these words for the first time, I was thinking "exactly". As far as I remember, by that moment, my attitudes to these very general questions were already fully formed and they just happened to agree with Feynman's.
Not all people always have the wisdom and courage to admit that "they don't know" or "they are uncertain about" something. Don't get me wrong: Lots of laymen heavily underestimate what science can already reliably explain and predict. Science knows the (nearly) fundamental laws underlying pretty much everything we have ever observed. And we more or less satisfactorily know how to deduce the successful effective theories from all fields of science out of the (nearly) fundamental ones. It's unthinkable for many laymen who are not "into science".
On the other hand, there unavoidably exists a point at which the current science simply doesn't know certain things. Some of them are too difficult; some of them are unknowable or unphysical. One place where you unavoidably find such questions is the cutting edge of research. If we knew all the answers to questions of a certain kind, we wouldn't have to do research. So it is simply obvious that the cutting edge of the research is full of unanswered questions or questions with uncertain answers. The cutting edge of the research may be perhaps defined as the collection of questions where the certainty about the answers drops below 100%, perhaps to 90%, perhaps to 50%.
It seems to me that most people are too impatient and sloppy when they're forming their opinions about too many questions. They often jump to a random answer to a question and then they only spend time by convincing themselves that it was the right choice. In the context of the ET discussion, I mean the difficult questions such as: Are we the only ones in the visible Universe? Is it almost certain that life arises on a hospitable planet similar to ours? Is it almost certain that intelligent life evolves from the primitive life? Are most ET civilizations saint or politically correct in one sense or another? And so on.
I believe that if one thinks about these things fairly, with some quality standards, it's obvious to him that science doesn't actually have evidence in one way or another. It doesn't have any direct empirical evidence. But it doesn't have any reliable enough theory, either. So it's just not right to pick one answer or another and separate oneself from all the people who happen to prefer other answers or those who admit their ignorance.
Before we pick a particular answer, we should be trying to answer the question whether a sufficient amount of evidence to answer this question may be available to humans now (or in the future). And we must be simply ready for the answer that the body of evidence is insufficient to decide. It's the case so often. It's hard to see why some people don't see it.
At the end, I believe that those people who have done any credible research must know very well that ignorance and uncertainty are omnipresent. People may believe many kinds of things but if you do the research, you will often become certain that their beliefs are due to prejudices, guesswork, group think – that the rational foundation is simply missing. You may employ your very special brain and extract the best possible answers, explanations, and evidence from the best libraries in the world. And the result is that there isn't any valid argumentation that proves or nearly proves that some answer to a difficult question is correct. And there are lots of superstitions around.
Very soft sciences and pseudosciences are a huge class of examples of bogus knowledge. Is the life expectancy longer for those who use fats and oils based on plants or animals? If you study the actual serious research, you will see that if a difference exists, the effect is so small that it couldn't have been settled with any real statistical significance. At least from a practical viewpoint, it just doesn't matter. Nevertheless, many people prefer to be attached to one answer or another. In both cases, their publicly stated opinion that there is a huge effect in one direction unmasks their ignorance about a rather clear result of the scientific research that the actual effect is very small i.e. close to zero.
The Standard Model allows us to calculate the probability amplitudes of processes involving elementary particles. The theory is well-defined and, aside from some tiny technical glitches that seem to be fixed by string theory, the mathematical formalism to produce the answers is universal and gives totally precise answers. The Standard Model is an effective theory which means that some ignorance inevitably lurks at higher energies or other extreme regimes.
But aside from this uncertainty about the fundamental laws – which is extremely important for pure theorists thinking like your humble correspondent, but it is not important in practice – there is the uncertainty about the applications. As you turn your attention from the elementary particles and processes to larger and more messy objects and phenomena, the quantitative answers become less precise, the formulae to calculate them have an increasing number of "buts" and disclaimers, and the uncertainty grows.
Science as we know it capable of producing satisfactory explanations for most answers to these "emergent questions" that we could have observed empirically. And we may predict the answers to similar enough questions even if we haven't observed the results directly. But then there are questions that are so different from everything we have observed – but so distant from the calculable fundamental laws of physics – that we simply can't know the answer at this stage (or any given moment).
The questions about the concentration of the extraterrestrial life (or extraterrestrial intelligent life) let alone the dominant political parties in the extraterrestrial civilizations surely belong to this category. We have observed no data describing the extraterrestrial civilizations. The only data we have accumulated show that the concentration of the extraterrestrial life is smaller than what would imply that life flourishes on Mars, Venus, and everywhere. It doesn't seem to be there.
At the same moment, we just don't understand the physical foundations of biology well enough to be sufficiently certain that the ETs must have the same bases of DNA – or the diversity in the DNA-like molecules may be huge. You may say that it would be surprising for a molecule that is as complicated as DNA (or RNA) to be basically unique. Could you really derive the structure of this complicated molecule from the Standard Model as its answer to the question "how does life store the information"? However, you may also say that it would be surprising for the choices of DNA-like design to be numerous given the fact that we have never encountered a single alternative.
We just don't know the answer. You may design a logically consistent system of answers including certain specific answers – but the point that many believers more or less deliberately overlook is that you may design a logically consistent system of answers that include some other answers, too. If and when there are many options, the consistency just isn't sufficient to isolate the truth.
It's possible that we will be able to get almost certain at some moment in the future. But it's not hard to see that this certainty can't exist now. If someone has discovered a different life with a similar but different DNA-like molecule underlying it, you would have heard about the news! And if someone were able to theoretically prove that DNA is unique or some other DNA-like molecule is unavoidably working in some conditions, you would know about it, too. Such results just don't exist. The observations aren't available. And the biologists aren't that good in producing physics proofs from the first principles.
Why do so many people feel the urge to pretend that they know so many things about the extraterrestrial civilizations when it's so spectacularly obvious that they know nothing about them at all? I think that the general "fear of ignorance" may be blamed.
It seems plausible to me that the anti-quantum zeal may be mostly explained by this "fear of ignorance", too. "Realism" in the sense of "interpretations of quantum mechanics" is the idea that the state of the physical system is knowable before/without an actual observation. Note that if I formulate the opinion of the "realists" in this way, it looks pretty much tautologically false. We only know facts about Nature from observations, so before/without an observation, we obviously can't know the answer. At this level, the quantum mechanical non-realism is nothing else than the insight that knowledge requires observations even though to turn it into a philosophical paradigm of non-realism, it must be expressed in slightly different words, using logically equivalent propositions.
Clearly, I can't rigorously disprove "realism" in this way. The "proof" above was cheating. After all, classical physics seemed logically consistent for centuries and it did admit the concept of the "state of a physical system before/without an observation". I can't know about the state of the physical system without my observations, but the laws of physics may still be compatible with the assumption that some metaphysical agent knows the state of the Universe at all times, independently of any observations, i.e. that He basically observes things at all times. Well, I am confident that the quantum mechanical revolution has ruled out this possibility. The observation – any "creation or accumulation of knowledge about the external world" – always modifies the state of the physical system. So there can't be any agent, not even a "divine" one, that could know things prior/without the observation. After all, Yes/No questions are linked to linear projection operators and those generically have nonzero commutators. So the sharp Yes/No answers to all of them (all physically meaningful questions about the state of Nature) simply can't exist simultaneously, not even from the viewpoint of a divine agent.
From a practical viewpoint, even if the state of a physical system existed before/without the observation, it wouldn't help anyone to predict things. Even if the information about an observable exists before the observation, you cannot get the information before/without your observation. So the assumption that the information exists before/without an observation is self-evidently useless for you – and for everyone else.
So why are so many people so desperate about convincing themselves that answers must exist before/without the observations? Maybe, the general pathologically irrational "fear of uncertainty" should be blamed for that. Just like people couldn't sleep without an answer to the hard questions about the extraterrestrials, they couldn't sleep if they had to believe that the answers to physical questions about observables before/without observations are fundamentally unknowable.
Well, I can sleep just fine. The evidence makes it almost certain that they are unknowable, indeed.
One common fallacy that allows these "people frightened by ignorance" to remain influential is the fact that many people often confuse the self-confident behavior with the actual expertise and knowledge. If someone produces some answers to some questions and acts self-confidently, many people automatically think that he or she must be smarter, more well-informed, and simply more correct than someone who says "I don't know" or "I am not certain".
Except that it's not the case at all. Wisdom often comes with modesty. The people who don't know and who admit that they don't are often smarter, more knowledgeable, and more correct. In many cases, they have done their homework. They have verified that the people who are certain about something actually use sloppy or downright incorrect arguments. They have seen that there are likely enough loopholes, gaps in the proofs, alternative explanations, and so on.
As I have previously mentioned, it's sometimes the other way around, too. People sometimes love when someone says that something is completely uncertain and those who state that they know the answers to some questions are sometimes automatically treated as heretics or bullies.
It is possible to err on both sides and people constantly err on both sides. We must realize that very often when there's some disagreement, the competing opinions are "asymmetric" in the sense that one side says that "we know a lot and the answers are this and that" while the other side says "we don't know and the answers to these and those questions may be many things or almost everything".
Whenever this happens and it happens very often (just think about the climate debate – which partially boils down to the disputable "certainty" of some people that they may predict the state of the atmosphere in the year 2100), people must be impartial and realize that both sides may be right a priori. It's because there are certainly questions that science has been capable of settling; and there are also undoubtedly questions that science hasn't answered (or reliably answered) yet.
It is very important for a scientist – but even for a layman – to listen to both sides of such exchanges because in general, both sides may be right (or at least, both sides may be holding and presenting some truly relevant evidence or arguments). Sometimes, those who say "we know almost everything" in a certain class of questions are right; sometimes, those who say "we are basically ignorant or uncertain about everything" are right.
If you decided to universally prefer those who say "we don't know anything", you will end up knowing nothing which is bad. If you decided to universally prefer those who say "we know basically everything", you will unavoidably believe lots of answers that are actually incorrect because these answers have been more or less randomly guessed and then rationalized and it's statistically implausible that all the guesses were right.
Aside from the art of picking one answer to a question or another, one should also learn the art of labeling questions "easier or harder to be settled". Some answers are known or knowable; others not so. And it can't be clear from the beginning in which group a particular question or set of questions belongs.
In this case, the truth is somewhere in between but where the "golden middle" lies depends on the situation so there's no universal yet reasonable way "what you should believe to be perfectly balanced", either. There are no universally applicable easy answers in science – and the same comment is true not only in science but also in politics and elsewhere.