In trying to find whether there is “something else out there” I have looked at three possibilities. One possibility was that there is nothing else, and modern science will eventually explain everything. That is, while there seem to be profound mysteries that presently cannot be explained by modern science, some new, perhaps apparently illogical, science will be developed to explain them.

Another possibility was that there will always be things that need a supernatural explanation, and there will be evidence and/or reason to recognise this. When I tried to find what could be justifiably said about this supernatural, the only things that I could find looked like something that might possibly be described by a strange new science – a science that seemed so different that it might also be above or beyond that of the natural material world. But I had to accept that that might be just the merest vestige of some unimaginable supernatural entity. I could see no reason to think that the supernatural would have the human-like characteristics that the religions attribute to it.

The third possibility was that there is no way of telling whether either of the first two possibilities is true. I think the third possibility is the most likely. But that is just my opinion.

In the discussion I briefly mentioned the scientific project SETI (Search for Extraterrestrial Intelligence). The idea behind this project is that communities of beings with advanced technologies may exist in other parts of the universe, and that we might be able to detect their existence. This is because it is assumed that they would be producing electromagnetic radiation similar to our television and other communication signals. Since the pattern of this “artificial” radiation is different from naturally occurring radiation from stars, we should be able to identify any of it that comes our way by using radio telescopes. During its decades of searching, the SETI project has detected brief patterns of radiation that at first looked promising, but it has yet to find any persuasive evidence. This does not mean, of course, that no such advanced communities exist elsewhere else in the universe.

I feel that my search for the possible existence of the supernatural is a bit like SETI. In a way, I feel that I have better evidence, however superficial it may be, for the supernatural than SETI has for advanced extraterrestrial intelligence. But whatever we might think the probabilities are, in both cases the evidence is insufficient to convince me either way.

This relates to an underlying theme throughout the chapters, that while we may try to check whether what we believe is correct, there are often hidden shortcomings and limitations in the ways we do the checking. I am referring not only to the many decisions we continually make on scant information and often at short notice, but also to the beliefs, arrived at unhurriedly, that guide our lives.

In presenting agnosticism from a range of perspectives I have attempted to confirm or refute the cases in support of religion and of atheism. In many cases I think I have come fairly close to complete refutation. But a near miss is still a failure. This failure might be seen either as justification of the agnostic perspective, or as incompetent inquiry or as evidence of some unconscious bias that has caused me to skew the arguments. Whatever readers decide about this, most will have either indulged or restrained a bias in their interpretation and assessment of what I have written. Some will think I am plain wrong.

While there many things we have good reason to be certain about, I doubt whether there is such a thing as absolute truth. It is not that I think there is no reality “out there” but because I think it is intrinsically impossible for any finite entity to have complete knowledge. And, despite the achievements of the sciences and other disciplines, human beings are constrained in what they can find out and understand. In some types of scientific cases I feel that we may be getting close to truth, and I find this fascinating and exciting.

But how close are we, and how could we ever be sure? Whenever some new insight is gained about the workings of the universe, it seems to open up new mysteries that challenge what had previously been thought to be true.

Despite this, inherent uncertainty is no excuse for not using the best evidence and the soundest reasoning we have in living our lives. And although even with sound evidence and reasoning we will not all come to the same conclusions, we will at least know the grounds from which we reached them.

I hope I have established not only the status of religious agnosticism, but also the desirability of caution, even of modesty, about beliefs of all kinds. This is not to dampen passion or action, but it is a plea that passion and action be guided by dispassionate consideration.