The simplest moral position is called the theory of “divine commands”, and it says that whatever God commands (or wants) is morally right. So murder is morally wrong because God commands us not to do it (or doesn’t want us to do it), but loving thy neighbours or enemies is morally right because God commands us (or wants us) to love them.

The theory of divine commands is widely thought to have been blown out of the water over two thousand years ago by an argument in Plato’s dialogue Euthyphro. Some philosophers say it is not really an “argument” so much as a devastating question.

In that famous dialogue, Socrates asks whether an act is “pious” because it is “loved by the gods”, or loved by the gods because it is pious. In modern terms, the question would go like this: Is it morally right because it is commanded by God, or vice versa? This creates a dilemma, the generally-agreed conclusion of which is that the theory of divine commands is mistaken, and that we must have reasons for making moral judgements that are independent of God’s commands or wishes.

I accept this conclusion. I agree with the mainstream view that the theory of divine commands has been decisively destroyed, and that the question Socrates asked was indeed devastating. But a very similar question can be asked in many other areas of human life, wherever we appeal to authority – which nowadays seems to be practically everywhere.

Socrates’ question has been widely discussed by philosophers over the ages. Some philosophers focus on the way God’s commands might be completely arbitrary. I want to focus on the way anyone who wants to follow God’s commands has to have some way of telling which commands are genuine. He has to have some way of judging who is a genuine God, or who speaks for a genuine God rather than a false idol. If he consults an oracle, he has to have some way of telling which oracles are trustworthy. There is simply no escape from the fact that at some stage he has to judge for himself, and come to a decision independently of what any authority tells him. No matter how much we may try to defer judgement and defer to others, there comes a point where we can defer to no authority at all: ultimately, we are on our own.

The respect for authority is directly opposed to the practice of philosophy, and inimical to the guiding spirit of philosophy, which is essentially to think for oneself. And yet this anti-philosophical spirit seems to have an immortal life, in the form of respect for expertise in general and an unquestioning trust in “science”. I call it an “unquestioning” trust when no question is asked about what to count as science (and what to dismiss as pseudo-science) beyond simply taking the word of some people regarded as experts. That is the very same as consulting an oracle on God’s commands. Tragically, that sort of trust is often exhibited by people who call themselves “sceptics”, who have really just substituted one oracle for another.

Suppose we accept for the sake of the argument that the practice of science is especially good, for some reason such as its unusual trustworthiness. (Let’s overlook the fact that science is essentially speculative and therefore uncertain.) Then let us ask our new version of Socrates’ devastating question: Is a practice trustworthy because it is practised by scientists, or is it practised by scientists because it is trustworthy?

If a practice is trustworthy because it is practised by scientists, then the more deferential among us might defer to scientists because they are authorities who can judge on our behalf what is trustworthy. The trouble is, because scientists enjoy such deference, everyone wants to call himself a “scientist”, and many of those who do are nothing of the sort. So we need some means of distinguishing genuine scientists from pseudo-scientists. History contains many examples of the latter – from alchemists and astrologers, to phrenologists, psychologists and sociologists. (You may have a slightly different list here, but that’s irrelevant.) As nowadays more than ever science is considered the highest and most trustworthy form of human thought, nowadays more than ever there are those who claim the honorific title of ‘scientist’, and those who claim it spuriously.

To defer to scientists, one needs to be able to judge who is a genuine scientist and who isn’t. To do that, one needs to be able to judge what science is, in order to check whether someone who claims to be doing science really is doing it. But in that case, one needs to have a means of judging what science is that is independent of what scientists practice.

Just as before, when trying to follow God’s commands, you cannot escape the fact that at some stage you have to judge for yourself.

The alternative approach is to say that the sort of thing scientists do is trustworthy not because scientists do it, but because it is trustworthy no matter who is doing it. It is trustworthy because of its methodology rather than the “authority” of its practitioners. Scientists recognize that this methodology is trustworthy and so employ it themselves.

In which case, fine. Once again, there has to be a means of judging what science is that is independent of who practices it. Whichever answer we choose, the conclusion thrust upon is that we need to judge for ourselves.

I often wonder why nowadays even more than before – when much of humanity consisted of uneducated peasants in the thrall of the clergy – respect for authority seems to guide every aspect of our existence. Perhaps it is because people are “off their guard” a bit, thinking they have successfully escaped the thrall of the clergy. But that is like sheep congratulating themselves on their individuality, when all that has happened is they have formed a slightly smaller herd of sheep that has broken away from the main herd of history. It is still a herd of sheep.