by Jill Tarter

Summer 2000

from SecularHumanism Website




The following article is from

Free Inquiry magazine, Volume 20, Number 3.


The statement that extraterrestrial intelligence exists or doesnít can have the parallel statement that God exists or doesnít.


Some people say thereís already sufficient evidence of existence for both. If you set aside abductions and miracles, itís true that the absence of evidence is not evidence of absence for either.


However, if and when one ever detects evidence of an extraterrestrial intelligence, it will break the symmetry of these two statements and, in fact, that evidence will be inconsistent with the existence of God or at least organized religions.

Itís all about space and all about time.


Technological civilizations cannot be co-located - that is they canít be close to us in space and in time - unless on the average such technological civilizations are long-lived. Iím not talking about 100 years or 1,000 years. Iím talking about the age of stars or galaxies.


Let me illustrate that with the Drake Equation, which in fact I hardly ever use.


An equation is nothing more than a lovely way to organize our ignorance. When you write an equation somebody expects you to calculate an answer. Itís impossible. There is no answer to this equation except by observation and experiment.

The Drake Equation says the number of civilizations in the Milky Way Galaxy with whom we could currently communicate can be estimated by taking the average rate of star formation in the Milky Way Galaxy - and really here we mean stars similar to our own sun that live long enough for evolution to be possible (if evolution elsewhere takes as long as it did on this planet) - by the fraction of stars that have planets.


We now know about extra-solar planets - the number is 40, and counting...


The equipment that we have on telescopes today is best at finding only very massive planets with very short-period orbits. Maybe ten years ago somebody would have bet that there were none. But, we still do not have instruments with sufficient precision to find other planets.


So, we know something about extra-solar planets, but not really a whole lot, particularly nothing yet about the number of earthlike planets in an average solar system.

Now we get into real speculation.

  • What is the fraction of all earthlike planets out there on which life begins?

  • And of that fraction of life-starts, how many ever develop an intelligence that we would recognize?

  • And of the intelligent species out there, how many of them develop a civilization and a communicative technology that can be sensed over the distances between the stars?

  • And last, how long does that civilization and that communication last?

Given all we know and all we really donít know, this equation degenerates to N is equal to or less than L. To be completely accurate, we can say that N is much, much less than L.

We can say the number of communicative civilizations in our galaxy currently is less than their age in years. Now I consider that the Milky Way Galaxy is very old and very large - 10 billion years old, 100,000 light-years across. We live out here in the boondocks. It contains 400 billion stars, about a quarter of which, 100 billion, are similar to the sun.


Let me calculate how many stars I would have to search to find one intelligent civilization. And then, what distance would I have to go out to search that many stars in the Milky Way Galaxy?

We have had communicative technology for about 100 years. If itís typical, I have to search about four billion stars to find one other intelligence. And that means that I would have to search almost 10,000 light-years, throughout our galaxy - 10% of the distance across the galaxy.


Suppose that the right age is something like 13,000 or 15,000, the amount of time weíve had civilization so far.


Then itís 1 in 30 million stars and Iíll find one within 1,700 light-years. If civilizations last a million years, then I only have to search 400,000, and Iíll find one with 430 light-years.


And if civilizations last 400 million years, then 1 in a 1,000 will be enough. And they will be within 50, 60, 70 light-years.

That 1 in 1,000 is currently where the most sensitive SETI searches are operating. For them to succeed, for terrestrial, primitive technology to find an extraterrestrial intelligence, means that they are going to be very old. So near-term success implies that the technology that we detect will be much older than our own.


Ultimate success we think out in generations. You canít necessarily draw the same conclusion.

Therefore it has to be possible to survive the kind of state we find ourselves in today - our technological infancy - without doing ourselves and our planet in. Such extreme longevity is totally inconsistent with organized religion as we know it. Iíll remind you that men never do evil so completely and cheerfully as when they do it from religious conviction.


Put another way, in general, bad people do evil things; good people do good things. But, it takes religion to make a good person do something really bad.

Organized religion is one of our greatest threats to survival. Across the spectrum of religions we have today, one of the most common elements is some form of prayer.


Ambrose Bierce defined ďto prayĒ as:

ďTo ask that the laws of the universe be annulled on behalf of a single petitioner confessedly unworthy.Ē

That frame of mind - a willingness to set aside the laws of the universe in favor of some higher authority - basically lets one off scot free. It allows individuals to evade the consequences of their actions, including the destruction of species and habitats.

Organized religion is an invention not only of our intellect but possible other intellects.


H.L. Mencken said:

ďThe most common of all follies is to believe passionately about the palpably not true. Itís the chief occupation of mankind.Ē

Steven Pinker tells us that the way evolution shaped human intelligence and the mind was to create a system of modules designed to figure out how the world works.


When youíre starting out you havenít figured out a whole lot yet.


Non-literate peoples routinely, therefore, invent ghosts that they bribe for good weather. And, they grant powers to ordinary objects. They donít invent totally different objects; they take the ordinary and make them more powerful.

So, organized religion is an invention of the mind, as envisioned by Steven Pinker. God is our own invention.


If weíre going to survive or turn into a long-lived technological civilization, organized religion needs to be outgrown. Religious wars traditionally have had secular cessations. Somebody imposes a treaty, but the conflicts really never end. There are some really horrific examples.

The only possible solution I can see to outgrowing religion as we know it today with its sects and denominations is the development of a universal religion with no deviations, no differentiations - absolutely global and compelling for all.


Such a religion might be able to coexist for a long time with technological development without precipitating the worst of human tendencies.

If that development is possible for any civilization, then I would speculate that, if and when we ever get a message, itís going to be a missionary appeal to try to convert us all.


And, on the other hand, if we get a message and itís secular in nature, I think that says that they have no organized religion - that theyíve outgrown it.