5.1.1.8 Omphalos and “Last Thursdayism”

Omphalos means “navel” in Greek. It consists of the idea that the universe and everything in it was created with the appearance of age and history in Biblical times. Adam and Eve were created with navels (thus the name), mountains came into existence pre-formed, seas already vast, caves already deep, stars already distant, and buried fossils having the appearance of great age. Because of God’s skill, his creation is indistinguishable from a truly ancient universe billions of years old. He is either tricking us or testing us.

A modern version of Omphalos is “Last Thursdayism”, which takes a more extreme position – the universe was created just last Thursday, and we were all created with implanted memories of fictitious events that we only believe occurred before that. In fact, it all may have just begun five minutes ago, as Bertrand Russell described in The Analysis of Mind,

“There is no logical impossibility in the hypothesis that the world sprang into being five minutes ago, exactly as it then was, with a population that "remembered" a wholly unreal past. There is no logically necessary connection between events at different times; therefore nothing that is happening now or will happen in the future can disprove the hypothesis that the world began five minutes ago.”

There are a near infinite number of different claims that share a similar structure with Omphalos and Solipsism (described in the previous blog entry), and they are equally irrefutable and just as strange. For instance, I could claim that an invisible leprechaun sits on my shoulder who created the universe, while you could claim that a invisible angel on yours deserves that distinction. Neither can be disproved. Every person on the planet could make a similar type of claim. They can’t all be true, and through the logical technique called “Overloading Objections” it can be shown that none are likely to be true. This technique doesn’t disprove these silly arguments. It just shows that if Solipsism and Ophalos can be true, then so can billions of other similarly formed assertions.

So, Omphalos shares with Solipsism and the infinity of parallel barren positions the trait of being invulnerable to criticism and disproof – and that is all they have. They are metaphysical tricks, not sincere philosophical statements. They do nothing to advance intellectual progress, but only block further discussion. They are nothing but immature philosophical "heckling" and intellectual vandalism whose only real purpose is to interfere with the real business of investigation.

The physicist, Sean Carroll, wrote in his blog, "Cosmic Variance":

... it makes no sense to act as if any of those (solipsism, brain in a vat, etc.) is the case. By “makes no sense” we don’t mean “can’t possibly be true,” because any one of those certainly could be true. Instead, we mean that it’s a cognitive dead end. Maybe you are a brain in a vat. What are you going to do about it? You could try to live your life in a state of rigorous epistemological skepticism, but I guarantee that you will fail. You have to believe something, and you have to act in some way, even if your belief is that we have no reliable empirical knowledge about the world and your action is to never climb out of bed. On the other hand, putting aside the various solipsistic scenarios and deciding to take the evidence of our senses (more or less) at face value does lead somewhere; we can make sense of the world, act within it and see it respond in accordance with our understanding. That’s both the best we can hope for, and what the world does as a matter of fact grant us; that’s why science works!

Likewise, the "Boltzmann Brain" (a scenario where our brains suddenly materialized out of a random collection of particles, and exist floating in space imagining the reality we think we live in) is just as unlikely, though not impossible. Again, quoting Sean Carroll, from his book, The Big Picture:

Is it possible that you and your surrounding environment, including all of your purported knowledge of the past and the outside world, randomly fluctuated into existence out of a chaotic soup of particles? Sure, it’s possible. But you should never attach very high credence to the possibility. Such a scenario is cognitively unstable, in the words of David Albert. You use your hard-won scientific knowledge to put together a picture of the world, and you realize that in that picture, it is overwhelmingly likely that you have just randomly fluctuated into existence. But in that case, your hard-won scientific knowledge just randomly fluctuated into existence as well; you have no reason to actually think that it represents an accurate view of reality. It is impossible for a scenario like this to be true and at the same time for us to have good reasons to believe in it. The best response is to assign it a very low credence and move on with our lives.

Young earth creationists use a form of Last Omphalos (in this case, claiming that the universe is only 6000 years old). They counter legitimate arguments such as those involving ancient supernovae and light from remote galaxies by saying that light from supposedly distant objects was created "in place", that god created the stars and their traveling photons simultaneously, giving only the appearance of having traveled for billions of years. Just as Adam didn't have to wait for seeds to grow into trees to bear fruit, we didn't have to wait eons for light from far away to reach us. This is a textbook example of special pleading (i.e., creating ad hoc arguments). It gives its defenders an infinite, unhindered ability to special plead against any evidence that exists: "It's that way because god made it that way, and we don't need to know why he did it". It is arbitrarily ad hoc, a wild card that answers all questions, intellectually dishonest, childish, naive, and deceptive.

Further, both of these perverse hypotheses about how reality is structured share another serious weakness. Omphalos and Solipsism could be seen as equally probable as the "ordinary world" hypothesis of reality (i.e., that reality corresponds roughly to what it appears to be). Given that each of them are unproven hypotheses, one cannot assert any to be superior to the other. However, the notion that these are empirically equivalent defines equivalence strictly in terms of the hypotheses' making the same predictions and accounting for the same observations. This overlooks other important considerations. Even if several hypotheses make exactly the same predictions and have explanations for observations, one of them may have more robust and complete explanations of the phenomena that are predicted, making that one more probable than the others. Simply because none of them are provable doesn't make them all equally likely. Thus, if explanatory success has a role in determining which metaphysical model we should prefer, then employing inference to the best explanation (i.e., abduction) would lead us to believe one of the hypotheses over the others.

In the face of arguments from solipsists, religionists, supernaturalists, and others who prefer a world of fantasy and miracles, the words of John Worrall, a philosopher of science, provide some perspective:

There is nothing which will compel the adoption of a realist attitude towards theories <of the the world around us>, but this leaves open the possibility that some form of scientific realism, while strictly speaking unnecessary, is nonetheless the most reasonable position to adopt.

Or, according to Sean Carroll,

We have every right to give high credence to views of the world that are productive and fruitful, in preference to those that would leave us paralyzed with ennui.

It is widely held that the most powerful argument in favor of Realism is the "no-miracles argument", according to which the success of science and realism would be miraculous if scientific theories were not at least approximately true descriptions of the world.

Many epistemologists have invoked abduction in arguing against this type of radical pure skepticism, their claim being that even though the skeptical hypotheses (i.e. - "nothing is real", or "history is not real") make the same predictions as the hypothesis that reality is how we ordinarily take it to be, they are not equally good explanations of what they predict. In particular, the skeptical hypotheses are far more intricate and complex than the “ordinary world” hypothesis. The ordinary world hypothesis requires no scheming or misdirection by a trickster universe, while the skeptical hypotheses involve a vast, universal conspiracy theory. Although we may not be able to prove that the "omphalos" or solipcistic explanation are false, by abduction, they are far weaker explanations than accepting reality as it appears. Choosing one of them over the simpler explanation would simply be contrary and obstinate. Invoking an aphorism coined in the late 1940s by Dr. Theodore Woodward, "When you hear hoofbeats, think of horses not zebras". Applied here, supporters of these far-out theories can offer no compelling reason for believing that one of us is dreaming, or all of us are dreaming, or the universe is a dream, or the universe was created only moments ago.

However, supporters of the ordinary-world hypothesis can offer every one of our experiences as solid evidence for that explanation of the world. The alternate theories can make no predictions, offer no explanations, and have every appearance of being ad-hoc. They exist only to fit the data, but have no explanatory or predictive power. "Ad-hoc" is Latin for ‘to that’ or ‘to the fact.’ An ad-hoc explanation is one that is constructed solely to save a hypothesis from facts which would disprove it; it has no independent justification. Any claim can be saved from negative evidence by modifying it, ad-hoc, in the fact of counter evidence. The more ad-hoc hypotheses needed to prop up a claim, however, the less plausible it is. Omphalos is ad-hoc in the highest degree. As a theory, it also lacks the properties of explanatory scope (ability to explain a wide variety of phenomena), explanatory power (ability to describe any one phenomenon in depth), fruitfulness (the ability of a hypothesis to successfully predict novel phenomena), consistency (freedom from internal and external contradiction), simplicity (not the brevity of the hypothesis, but the number of assumptions it has to make), and conservatism (how well the hypothesis fits with what we already know). Although it successfully accounts for the "data" of the world, it is a far weaker theory of reality than scientific realism and philosophical naturalism. There are also an infinite number of Omphalos/Last Thursdayism hypotheses (for example, last Fridayism). Which of these should we believe, or should be believe neither?

Last Thursdayism and Solipcism, each in their own way, deny the reality of the external world, or that history exists. Science, and philosophical naturalism, take as a fundamental premise that external reality exists, and that we humans can understand that reality - that we are capable of knowing it. Any claim which asserts that this premise is false - that what we see is an illusion - is invulnerable to a rebuttal from naturalism. Any evidence that naturalism would bring against this claim orginates in that external world, and therefore is suspect. In a conflict of world views, once a debate leaves the empirical, then naturalism cannot speak to it, since it takes as one of its premises the existence of the real world, and the reliability of empirical evidence. These are axioms that cannot be proved, but must either be rejected, or be accepted as self evident and the most likely explanation for our experiences of reality (for other axioms of naturalism, see "Assumptions of Science").

We could say that this is a limitation of the naturalistic worldview, and it probably is. So be it. It is a limitation of naturalism in the same way that the requirement that we accept Euclid's postulates is a limitation of Plane Geometry. If on the first day of a Geometry class, the students wanted to debate Euclids 5th postulate concerning parallel lines, rather than moving on with the course material, that is certainly an option, but it spoils the whole point of taking the class. Philosophical naturalists have no interest (and no expertise) in debating metaphysical philosophies which deny empiricism and external reality. They will readily admit there is no certain proof that reality exists, and then move on to other, more interesting, areas.

We have seen that Solipsism, Last-Thursdayism, "Brain in a jar", and Natuarlism all can account for our experiences. When the same evidence is explainable by several theories, we say that the evidence "underdetermine the theories". For example, we have a theory that when several hours of night has past, the sun will rise. Another theory that accounts for our experience so far is that for all of history the sun has risen, but starting tomorrow it will not do so. Both theories explain the evidence so far. Which of the theories, then, is better? James Ladyman summarized Carl Popper's approach to resolving multiple hypotheses that account for the same evidence in his book, Understanding the Philosophy of Science, which I paraphrase here:

For any theory H there is always another theory G such that:

1. If H & G are weakly empirically equivalent (i.e., they both account for the observable evidence) then there is no reason to believe H and not G.
2. H & G are weakly empirically equivalent.
3. Therefore, there is no reason to believe H and not G.

This is potentially a real problem for the scientific realist because, if it is correct, there are always rival theories we have not thought of, which fit all the data that support each of the best current scientific theories. If this is the case, why should we believe our best theories and not the skeptic’s alternatives? However, this argument may be challenged by denying the first premise, in other words, by arguing that the mere existence of a rival hypothesis consistent with all the data so far does not mean there is no reason to prefer one of H and G. Hence, for example, Popper argued that if G is ad hoc, and entails no other empirically falsifiable predictions, then it should be ignored.

Of course Popper didn’t think we should believe H either, but it is easy to adapt his response to defend an inductivist approach to the underdetermination problem. Hence, it might be argued that if H has previously been predicatively successful, and G is ad hoc in the sense of being introduced merely to accommodate the data without entailing any new predictions, then, given the past success of the overall method of believing empirically successful theory (H) over the ad hoc one (G), we have inductive grounds for thinking H and not G is likely to be true.

Theory "H" is Naturalism, and theory "G" is any of Solipsism, Last-Thursdayism, "Brain in a Jar", Young-Earth Creationism, or any other religion/superstition-based explanation for reality. Each of these theory "G"s offer no new predictions (and never have predicted any past events either), seem ad hoc, and are clearly attempts to harrass and nip at the heels of Naturalism, which is the only theory that has a successful history of explanation, description, and prediction. Given Popper's (and Ladyman's) explanation, we have every reason to believe "H" (Naturalism) and none of the competing explanations.