Epimenides was an ancient Greek philosopher and poet from the island of Crete.  Nowadays, he has three claims to fame: being quoted by St Luke; being quoted by St. Paul; and being quoted by Aristotle. His philosophy is remembered for exactly one sentence. What he said was, 'Cretans are always liars'. Since he himself was a Cretan, with a bit of imagination one can crispen this up to read, 'This statement is false.'

"This statement is false" : a very odd sort of sentence. If we assume it's true, it proclaims itself false, whereas if we assume it's false, we find that it agrees with us, which makes it look as though it's true. Such paradoxes are useless in themselves, but have the greatest value in testing reasoning; any system of thought that logically leads to paradoxes must be wrong in some way.

Modern science is the largest philosophical enterprise ever attempted by mankind. It is the study of cause and effect, based on the testing of hypotheses by designing and carrying out critical experiments, that is, tests designed to make the hypothesis fail if it's going to.

A hypothesis that fails the experimental test is simply wrong, and no more time need be wasted on it.  A successful hypothesis becomes more and more firmly established with every experimental success—though never quite immovable. This is the enormous advantage experimental science has over every other branch of inquiry: our fallible ideas can be compared against the crib sheet of a uniform and unvarying nature.  Experiments can be reproduced by anyone with the skill and the money.  As far as material results are concerned, science has been a brilliant success.

Science has the defects of its qualities, however. Rejected theories are simply discarded, which is quite right as far as it goes; but less creditably, old ones are often ridiculed by teachers, who pass this nasty habit on to their students. In my education, it was planetary epicycles, the particle theory of light, the phlogiston theory of chemistry, and anything Aristotelian.  All of these ideas were in reality held by the most brilliant scientists of the day: Ptolemy, Newton, Boyle, Priestley and Aristotle (who gets a specially bad rap).

Students are thus socialized to regard old ideas with amused indifference, and the content of their education provides little help outside a narrow field. For instance, we physicists use a mathematical technology that enables us to do exact reasoning of extreme complexity.  It is somewhat mechanical, though, and it only works on concepts that are exceptionally well defined.  Physics can be very complicated, but it doesn't require the same subtlety of thought needed for correct handling of many more familiar concepts such as mind and existence and God. Scientific training just doesn't develop the kind of extended critical thinking and respect for the history of ideas that are needed for the more difficult and hence slower-moving disciplines of philosophy and theology. Such training makes for good scientists but very poor philosophers.   (Some philosophers are pretty terrible at it, too.)

Science is all about cause and effect, but we need to be a little more precise about that. Aristotle usefully identified five types of causation: logical cause, final cause, formal cause, material cause, and efficient cause.  Formal cause is relevant mainly to a Platonic view of reality that we don't have space for here. Material cause is what it sounds like: a nail is made of steel, whose strength and toughness enable it to do its job.  Efficient cause is the answer to a `how' question—`how did that nail wind up sticking into this wall?' `I hit it with a hammer.'  Final cause (or teleology) is the answer to a `why' question: `Why is the nail sticking into the wall?' `I want to hang a picture.' Logical cause answers a `how do you know' question: `How do you know that part of the nail is inside the wall, when you can't see that part?' `Well, I saw it go in; I know it's still there because it is still mechanically strong—nails do hold things together. I have pulled out other nails in one piece, and even while it's inside it can be detected by an instrument such as a magnet or an x-ray machine.'

When a child asks, `Why is the giraffe's neck so long?', we give a teleological answer: `So it can eat the leaves way up high on the trees'. A scientific answer would have to bring in random variations and natural selection for a particular ecological niche—which would be very unsatisfying to the child.  The question is perfectly legitimate; it just isn't a scientific question, because it doesn't deal with efficient causation.  Teleology is the story that gives facts their meaning.

The idea of science is to study efficient cause in an organized way, in order to discover the laws of nature, and then to use the laws we've discovered to control various bits of nature for human benefit. Formal and material cause are of little concern for science, and any suggestion of teleology is quite rightly excluded there.

Immersed as they are in this study, surrounded by the evidence of their own success, many scientists have begun to believe that efficient cause is all there is.  This is to say that all legitimate questions can be settled by the methods of science, and all other questions are therefore illegitimate. This is a disastrous error.  Let's look at why.

Albert Einstein gave a talk to the International College of Surgeons in 1950, which was recently republished in a journal read by most practicing physicists.[1]   It is entitled `Physics, Philosophy, and Scientific Progress', and coming as it does near the end of his life, it has a reasonable claim to be a statement of his mature philosophical position. We will return to this remarkable speech (see If Nature Has Laws, How Can God Do Anything? and the forthcoming article on Thought) but at present let us concentrate on a few paragraphs at the end. The point here is not to pick on a mighty opponent who is now safely dead; Einstein has stated the views of the average scientific rationalist with great clarity and directness.

Under the impression of the profound changes that scientific thinking has experienced since Galileo, the question arises: Is there nothing at all that has remained stable in all this change? As a matter of fact, one easily recognizes certain principal features to which science has firmly adhered since those times.

First: Thinking, alone, can never lead to any knowledge of external objects. Sense perception is the beginning of all research, and the truth of theoretical thought is given exclusively by its relation to the sum total of those experiences.

Second: All elementary concepts are reducible to space-time concepts. Only such concepts occur in the 'laws of nature'. In this sense, all scientific thought is 'geometric'. A law of nature is expected to hold true without exceptions; it is given up as soon as one is convinced that one of its conclusions is incompatible with a single experimental fact.

Third: The spatiotemporal laws are complete. This means, there is not a single law of nature that, in principle, could not be reduced to a law within the domain of space-time concepts. This principle implies, for instance, the conviction that psychic entities and relations can be reduced, in the last analysis, to processes of a physical and chemical nature within the nervous system. According to this principle, there are no nonphysical elements in the causal system of the processes of nature. In this sense, there is no room for 'free will' within the framework of scientific thought, nor for an escape to 'vitalism'.

The first thing to note about these principles is that they aren't scientific statements. That is to say, they don't rest on inferences from data—we're doing philosophy here, not physics. The first one is an old philosophical commonplace: we learn about the outside world only through our senses. The second states the scientific method in a nutshell.  It can be restated to say that things in the world have efficient causes, that these causes are observed to operate by certain laws, and that we learn these laws by the method of hypotheses and experiments. The third principle is a pure statement of faith; that our success in applying these laws gives us confidence that everything can be understood this way: the world is a pure mechanism.

Principles 1 and 2 can be comfortably shared by scientists of religious and nonreligious outlook—both Thomas Aquinas and Karl Marx would nod their heads in assent.[2]

The third principle is another matter. All thoughtful people[3] accept that there is a physical mechanism for all physical processes; there is no point at which we break off and say `at this point God intervenes' and then continue with our causal explanation. But that's not what Einstein is claiming here. He's making a much stronger claim: that the physical mechanism is all that exists—with no exceptions—and that is quite false.

We'll get to why it's false in a moment, but first let's look at some of its implications. If free will is an illusion, then morality is also an illusion, because it is concerned only with free choices; an act is not immoral if it couldn't have been otherwise. Thus on this view, we have no rational basis for disapproving torture, or murder, or pollution, or anything else at all; religion and morality and human feeling are all alike illusions.[4]

As honest people, we ought to respect truth enough to face these consequences, if they were really demanded by logical consistency, but they aren't: you see, on this view, science and thought are illusions as well. While assuming that everything without exception is ruled by the iron law of physical causation, at the same time Einstein assumes that his own thought is somehow free and logically valid. Both can't be true: there's a chasm there at his feet, between the world of efficient causation and the operation of his own mind. This is a vitally important point which is easily glossed over, so we'll spend a little time on it.

On Einstein's view, consciousness is nothing more than the constantly changing states of our brains, with each state corresponding to the mental events occurring at that moment, such as admiring a sunset or pursuing a chain of reasoning. Reasoning then is merely a succession of states of the brain, following each other with the inevitability of physical causation, like the planets in their orbits. Each step of an argument would have to correspond in some way with a definite set of states of the brain, and the sequence would be determined by physical causation. But this succession has no necessary relation to logical causation whatsoever; Einstein's brain and a madman's are equally mechanical, and therefore equally irrational.  

Don't misunderstand here: the running of the brain-machine would be 'logical' in the sense that a correctly programmed computer is logical—that is, it would move from state to state in a predictable sequence.  But the final result of a computer program has meaning only if there's someone outside it who has programmed it to do something in particular, and also someone to give the result its meaning through some correspondence, e.g. between black squiggles in white columns and my bank balance.  It has to be for something; otherwise it's just pixels.

The kind of logic we're talking about here is logical reasoning, where particular thoughts logically correspond to certain outside things or events, as curves on a map correspond to roads and rivers, and allow us to reason correctly about those outside things.  It's this correspondence that makes it possible for our thought to be about something, and that's what can't happen if the mind is a mere machine—there's no someone there to supply the meaning.

Coming back to the main argument: if thought is really only a sequence of states of the brain, determined by physical causation, then logically right and wrong conclusions are equally invalid, because each is the predetermined outcome of a sequence of efficient causes. Logical cause then has no possible means of influencing the outcome of the argument, so in such a world, logical thought cannot even exist.

Even if at some point the physical state of the brain and logical state of the argument correspond, as soon as any difference arises the two will diverge irreparably; if the logical sequence of the argument exerts no influence on the physical brain, then there is no way to correct or even notice the divergence. This point is really the key: there is no way for logic to guide the operation of our minds, if those minds are really only complicated machines. Einstein has cut off the branch he was sitting on; if his views are valid, he cannot consistently hold them. Crispening this up a bit as before, we can say "This statement cannot be consistently held." Not precisely Epimenides, but close enough to be his twin.  A logical paradox has turned up in the midst of scientific philosophy: something has gone seriously wrong.

The good news is that it's the third principle causing the trouble, because the third principle isn't really part of the scientific method. Principles 1 and 2 are enough to deduce laws from experience, so number 3 isn't needed for that. Its real importance is in motivation; believing that the laws of nature are uniform and complete gives atheist scientists confidence that their program can really be carried out.

Theist scientists (such as the present writer) need confidence of a similar sort, but ours comes from believing that the universe was made by God, a God of order and not of chaos, who does not rule by whim, but keeps the universe running from moment to moment—"In Him we live and move and have our being".[5]   Theists and atheists do science in much the same way, with the same experimental program, the same critical attitude to evidence, and the same exclusion of teleology. Einstein's third principle makes his whole scientific program self-contradictory, so it has to go. This weakness is not shared by the theist approach, which after all is where modern science began. Since it is only this article of scientific faith that conflicts with religion, science does not disprove Christianity or any other kind of theism; in fact, theism can prevent science from disproving itself.

[1] A. Einstein, ‘Physics, Philosophy, and Scientific Progress’, Physics Today, June 2005.

[2]  Aquinas and Marx would differ about the source of some things learned through prayer and visions, but not even a mystic would rely on those for scientific measurements.

[3] Thoughtful modern people, anyway, as well as thoughtful medieval people and thoughtful people in classical antiquity, whether atheist, pagan, or Christian.  Divine providence and miracles are discussed in other articles.

[4]  None of this is a personal criticism of Einstein, who like most scientists was much better than his principles (see Rhetoric); he worked very hard for many humanitarian causes, including nuclear disarmament and international peace, but this should not be allowed to obscure the fundamental incoherence and inhumanity of his philosophy.

[5] Acts 17:28—a quotation from Epimenides' poem Cretica.