Earlier this week I presented a talk at the 2018 Australasian Astrobiology Meeting, with the objective of showing where life might be found elsewhere in the Universe, and as a consequence I shall do a number of posts here to expand on what I thought about this meeting. One presentation that made me think about how to start this series actually came near the end, and the topic included why do scientists write blogs like this for the general public? I thought about this a little, and I think at least part of the answer, at least for me, is to show how science works, and how scientists think. The fact of the matter is that there are a number of topics where the gap between what scientists think and what the general public think is very large. An obvious one is climate change; the presenter came up with a figure that something like 50% of the general public don’t think that carbon dioxide is responsible for climate change while I think the figures she showed were that 98% of scientists are convinced it does. So why is there a difference, and what should be done about it?
In my opinion, there are two major ways to go wrong. The first is to simply take someone else’s word. In these days, you can find someone who will say anything. The problem then is that while it is all very well to say look at the evidence, most of the time the evidence is inaccessible, and even if you overcome that, the average person cannot make head or tail of it. Accordingly, you have to trust someone to interpret it for you. The second way to go wrong is to get swamped with information. The data can be confusing, but the key is to find critical data. This means that when making a decision as to what causes what, you put aside facts that can mean a lot of different things, and concentrate on those that have, at best, one explanation. Now the average person cannot recognize that, but they can recognize whether the “expert” recognizes it. As an example of a critical fact, back to climate change. The fact that I regard as critical is that there was a long-term series of measurements that showed the world’s oceans were receiving a net power input of 0.6 watt per square meter. That may not sound like much, but multiply it over the earth’s ocean area, and it is a rather awful lot of heat.
Another difficulty is that for any given piece of information, either there may be several interpretations for what caused it, or there may be issues assigning significance. As a specific example from the conference, try to answer the question, “Are we alone”? The answer from Seth Shostak, from SETI, is, so far, yes, at least to the extent we have no evidence to the contrary, but of course if you were looking for radio transmissions, Earth would have failed to show signs until about a hundred years ago. There were a number of other reasons given, but one of the points Seth made was a civilization at a modest distance would have to devote a few hundred MW power to send us a signal. Why would they do that? This reminds me of what I wrote in one of my SF novels. The exercise is a waste of time because everyone is listening; listening is cheap but nobody is sending, and simple economics kills the scheme.
As Seth showed, there are an awful lot of reasons why SETI is not finding anything, and that proves nothing. Absence of evidence is not evidence of absence, but merely evidence that you haven’t hit the magic button yet. Which gets me back to scientific arguments. You will hear people say science cannot prove anything. That is rubbish. The second law of thermodynamics proves conclusively that if you put your dinner on the table it won’t spontaneously drop a couple of degrees in temperature as it shoots upwards and smears itself over the ceiling.
As an example of the problems involved with conveying such information, consider what it takes to get a proof? Basically, a theory starts with a statement. There are several forms of this, but the one I prefer is you say, “If theory A is correct, and I do a set of experiments B, under conditions C, and if B and C are very large sets, then theory A will predict a set of results R. You do the experiments and collect a large set of observations O. Now, if there is no element of O that is not an element of R, then your theory is plausible. If the sets are large enough, they are very plausible, but you still have to be careful you have an adequate range of conditions. Thus Newtonian mechanics are correct within a useful range of conditions, but expand that enough and you need either relativity or quantum mechanics. You can, however, prove a theory if you replace “if” in the above with “if and only if”.
Of course, that could be said more simply. You could say a theory is plausible if every time you use it, what you see complies with your theory’s predictions, and you can prove a theory if you can show there is no alternative, although that is usually very difficult. So why do scientists not write in the simpler form? The answer is precision. The example I used above is general so it can be reduced to a simpler form, but sometimes the statements only apply under very special circumstances, and now the qualifiers can make for very turgid prose. The takeaway message now is, while a scientist likes to write in a way that is more precise, if you want to have notice taken, you have to be somewhat less formal. What do you think? Is that right?
Back to the conference, in the case of SETI. Seth will not be proven wrong, ever, because the hypothesis that there are civilizations out there but they are not broadcasting to us in a way we can detect cannot be faulted. So for the next few weeks I shall look more at what I gathered from this conference.