Updated to ask readers more directly for their thoughts, if you have any...

A random thought.  Suppose we ask whether the world has a Beginning or an End, or whether it is eternal is one or both directions.  It seems like there are 5 possible views, which I will name by association to various cultural groups who supposedly have had these views:

1.  Norse view: the world began, and it will end.
2.  Greek view: time is infinite in both directions
3.  Hindu view: time goes in a circle
4.  Hebrew view:  the world began, but it will never end.
5.  Nobody ever: time had no beginning, but it will still end!

I find it interesting that the first four views all have some intuitive appeal, to different people, but the fifth view just seems horribly wrong and perverse!  Why do you suppose that is?

My best guess is that there's is a certain obvious symmetry to treating the past and future in the same way, which makes views (1-3) seem reasonable.  And there is also an argument that the past is not like the future, but if so it had better be like (4) rather than like (5)!  I guess we all know deep down (it's really the Second Law of Thermodynamics) that it makes sense for the universe to start from a simple initial condition and then develop complexities from there.  But if we have to deal with infinite regresses AND we don't even get an eternal universe out of it, that seems a bridge too far... but if anyone has any further thoughts on this, I'd be interested.

My cultural names are a brutal oversimplification, and you shouldn't take my assigning these views to different cultures too literally.  For one thing, there were lots of different Greeks and there are lots of different Hindus who believe all sorts of different things.  For another, there is a conceptual difference between the world—in the sense of an ordered cosmology with a history—beginning, and time (a much more abstract notion) having a beginning. It takes a certain amount of intellectual sophistication to think about the latter question.

Norse mythology begins with fire and ice swirling around a bottomless pit for aeons; it is only later that a bit of fire strikes a bit of ice and spontaneously generates a giant and a cow, from whom later the jotun and gods emerge by various removes.  (As you can see, the Norse were ultimately Materialists even about their so-called divinities.)  At the end, the cruel jotun defeat the merry gods and the world is destroyed, plunging back into chaos.  So it's not really clear that time has a beginning or end, just that the story has a beginning and an end.

The Hebrews had the notion of divine Creation in Genesis 1:1 and elsewhere, but it is controversial whether Genesis 1:1 actually teaches the creation ex nihilo of later theology.  St. Augustine is usually credited with the idea that there was not even time before creation, but in fact Philo, a 1st century Hellenistic Jew, got there first.

Similarly, our current best "concordance cosmology" appears to begin with an initial singularity, but has no end in time.  (Well, really we should talk about spacetime, which allows time to end in some places, e.g. inside black holes, but not others.)  This appears at first sight to be like the Hebrew view.  At late times the universe expands exponentially forever, thinning matter out to a very cold but finite temperature.  This is in accordance with the Generalized Second Law of Thermodynamics, which tells us that the universe will reach a boring maximum entropy state at late times.   Thus, the story ends at finite time, and we really have the heroic defiance against inevitable destruction, as in the Norse view.

Even in Hebrew cosmology, there is that little matter of the whole universe being destroyed and then recreated again:

“See, I will create
new heavens and a new earth.
The former things will not be remembered,
nor will they come to mind.
But be glad and rejoice forever
in what I will create,
for I will create Jerusalem to be a delight
and its people a joy.
I will rejoice over Jerusalem
and take delight in my people;
the sound of weeping and of crying
will be heard in it no more.

Never again will there be in it
an infant who lives but a few days,
or an old man who does not live out his years;
the one who dies at a hundred
will be thought a mere child;
the one who fails to reach a hundred
will be considered accursed.
They will build houses and dwell in them;
they will plant vineyards and eat their fruit.
No longer will they build houses and others live in them,
or plant and others eat.
For as the days of a tree,
so will be the days of my people;
my chosen ones will long enjoy
the work of their hands.
They will not labor in vain,
nor will they bear children doomed to misfortune;
for they will be a people blessed by the Lord,
they and their descendants with them.
Before they call I will answer;
while they are still speaking I will hear.
The wolf and the lamb will feed together,
and the lion will eat straw like the ox,
and dust will be the serpent’s food.
They will neither harm nor destroy
on all my holy mountain,”
says the Lord.  (Isaiah 65:17-25)

It's really this "new heavens and new earth" that will last forever.  Christianity is about Death and Resurrection, both for the universe and for each person.  Science can get us as far as the doomed-to-die bit, but it can't get us any farther.  That is Law, the rest is Grace, revealed in Jesus Christ.

## Reparameterizing Time

In recent posts I've been discussing whether the universe began or not.

Perhaps the most important issue which I have not yet discussed, is the idea (I think originally due to Charles Misner, first pointed out by St. Edward Arthur Milne, and independently by St. Charles Misner) that it may not be well-defined whether time has a beginning or not.  That is, suppose you have a model in which there is a time coordinate $t$, and time has a beginning in the sense that the only allowed times are $t > 0$.  Well, in General Relativity we are free to use whatever time coordinate we like, and nothing stops us from defining a new time coordinate in terms of the old one, let's say $\tau = \log(t)$.  If you look at a plot of the log function, you'll see that $\tau$ ranges from $-\infty$ to $+\infty$.

However, this type of time reparameterization may not be very physical once you get down to the Planck time, about $10^{-43}$ seconds, when quantum gravity effects become important.  Times less than that might not be well-defined.  In any case, the Misner argument suggests that we need to be more careful to define what we mean by time having a beginning.

Similarly, atheist philosopher Quentin Smith has argued that the standard Big Bang Model is inconsistent with divine creation, due to it not really having a beginning, even though the past is finite.  Smith argues that because the time $t = 0$ is singular, technically it shouldn't be included in the spacetime, so actually only times with $t > 0$ exist.  That means that there is no initial moment of creation, and therefore, he claims, God cannot have created the universe.

This is somewhat reminiscent of Hawking's claim that the no boundary proposal doesn't have the right sort of beginning, and it seems to me that my Fuzzing into Existence post is also applicable.  If God is like an author, then he can make a story in which time works in whatever way he pleases.

According to Smith, each time $t$ exists because the preceding times exist, and indeed the laws of physics hold at a given time $t$ (according to him) because they hold at earlier times.  Since each moment of time is fully explained by those before, he claims that the universe is therefore self-caused and therefore fully explained, with no more explanation possible.  (Of course, if time is continuous, then we could make a similar infinite regress of times going back closer and closer to any finite time $t$.  Smith has to struggle a bit to explain why his argument doesn't apply there...)

Now to me, this seems like the sort of explanation which is really no explanation at all.  A satisfying worldview should explain as much as possible with as few assumptions as possible.  If the laws of physics have some property $X$ (e.g. having an electron field, or whatever) now because they were like $X$ a minute ago, and so on all the way back arbitrarily close to the beginning, that doesn't in any way satisfy my curiosity about why they are like $X$ instead of some other way $Y$ (say, having no charged particles).  For if they had been $Y$ for all time, I could have made the same argument.  So it seems that there is a potentially meaningful question "Why are the laws of physics like $X$ rather than like $Y$", which Smith's statements do not really explain.  Maybe there is no explanation, and we have to take $X$ being the way it is as a fundamental fact.  But to say that there could not possibly be an explanation seems rather dogmatic.

And if God exists, then he can explain this fact.  God's will chooses what the laws of physics will be for all time.  So he can choose for the universe to be like $X$ instead of like $Y$.  This would be the fundamental explanation.  Whether or not it is a useful explanation for us as human beings, would depend on whether our puny minds can identify the actual reasons why God might prefer $X$ over $Y$.

The Kalam argument has some intuitive appeal if you think that the universe could not have begun without some causal reason.  Evaluating this claim requires an analysis of what causation is, and why one would think in various situations that a cause is necessary.  But the first preliminary question is whether there are any facts to be explained by the putative cause.  It seems to me that there are.

All of the same reasoning about $X$ and $Y$ would also apply if time stretches back to $-\infty$.  There would still be various timeless facts about the universe which would not really be explained by the infinite regress.  This suggests that the Kalam argument may be misguided to the extent that it attempts to prove God from a temporal beginning a finite time in the past.  The most important issues are the same whether time goes back finitely or infinitely.

But having said all this, it does seem a little bit weirder that the universe should exist for a finite amount of time with no external explanation, than that it should exist for an infinite time with no explanation.   Historically, many materialists (such as Lucretius) have believed that time is infinite, due to their belief that it is impossible for something to come from nothing.  Conversely, monotheists have mostly believed that the universe has a beginning, either for philosophical reasons or because the Bible says so.  (St. Thomas Aquinas argued that God could have created an infinite past, but that divine revelation tells us he didn't.) To that extent, Big Bang cosmology appears to vindicate the standard religious view over the standard nonreligious one.

(Of course, the same cannot be said if—unlike St. Thomas or St. Augustine—one also takes the 6 day creation about 6,000 years ago literally.  Some fundamentalists have argued that this problem can be solved by reparameterizing our coordinate system, but that just seems silly to me.  Also, the days are not in the right order to correspond to the scientific chronology.)

But a Theist could believe that God created time going back infinitely, without contradicting themselves, so long as they are prepared to be flexible about what "creation" means.  Similarly, an Atheist could believe that the universe just started existing 13.8 billion years ago for no reason, without contradicting themselves, so long as they are prepared to be flexible when deciding when explanations are called for.  All four views are logically consistent; the real question is which viewpoint explains the most with the least.

Posted in Physics, Reviews, Theology | 8 Comments

## Portuguese translations

I'm pleased to announce that some of my blog posts have been translated into Brazilian Portuguese.  St. Felipe of Olhar Unificado (added to blogroll) has translated the following posts:

Castidade: Não é apenas para religiosos

Deus das Lacunas

Depressão

If you can't tell which posts of mine these are translations of, then this new feature might not be for you!  Felipe also has a bunch of his own writing on Science and Religion on Olhar Unificado, which I have added to my sidebar, but I can't say much about it, other than that it appears to be composed of words relevant to the topic.  There are, however, pictures.

Regarding the post on chastity, I don't know how it reads to someone who actually understands Portuguese, but just looking at the words, my talk about sex and romance seems ever so much more impressive in a Romance language!

As Felipe comes out with more translations, I will update the list on this post (without making any other announcement).  Thanks so much to Felipe for his endeavers.

Posted in Blog | 1 Comment

## Moving to the Institute for Advanced Study

In case you are wondering why I haven't been posting very much recently.... My postdoc at UC Santa Barbara ends this month, and on Sept 1st I will be starting an exciting new postdoc at the Insititute for Advanced Study near Princeton, as announced earlier.  I'm looking forward to some great conversations with people at the IAS and at Princeton.

So I've been rather tied up with finishing projects and packing books, not to mention two physics workshops I went to at McGill and at U British Columbia.  If there's ever a time when one is tempted to forswear possessions all together, it's when one is trying to clear out an apartment for a move.  Maybe we forget sometimes how practical the advice of Jesus is, to store up our treasures in Heaven rather than on Earth.

Really, it's kind of surprising I posted even once this month.  Hopefully things will be more peaceful once I arrive at Princeton, at least before all my stuff catches up with me!

Posted in Blog | 3 Comments

Those who have been following the debate between St. Craig and Carroll, or my own recent posts about it, might also be interested in the viewpoints contained in the following articles:

Carroll on laws and causation (St. Feser)

Cosmology and Theology (Stanford Encyclopedia of Philosophy)

Just to make things a bit more random, about a year ago my brother (St. Lewis) wrote a blog post about data loss and death.  This post was very difficult for me to read.  Death is not just a big problem but also a little problem, and that is why even children instinctively know about it.  Fortunately the Lord is greater than death, and will wipe away every tear from our eyes (Rev. 21:4).

I am reminded also of the words of the Lord, when he appeared to my best friend St. Yoaav three times in a dream, saying "I am a God of little things, and little things are preserved in me." (cf. Zech. 4:10, written when the Jewish Temple was being rebuilt by Zerubbabel in 516 BC.)  This occured at a time when he was getting serious about relating to God personally through prayer, but before his conversion to Christianity (from Judaism) the following year.

But we shouldn't get so distracted by our own little tragedies that we forget that we're destroying our own planet.  Some Christians think that because Jesus is going to come back soon, we don't need to take responsibility for the environment, because "people are more important".  They must not have read the passage of Scripture where Jesus says that "you do not know the day or the hour" (Matt. 25:13), or the place where it says that God will "destroy those who destroy the earth" (Rev. 11:18).  If the Master is a long time coming back, then how are we going to take care of all these people once our natural resources are all shot?  And when he does come back, he will judge how well we have fulfilled our responsibilities, one of which is to take care of God's creation as stewards.

True, God will restore all things in the end.  But that doesn't mean we won't be held responsible.  If you suffocate somebody in their sleep to get their money and then—surprise!—10 minutes later Jesus comes back and all the dead are raised and it's the Final Judgment, do you really think you won't be regarded as a murderer because, after all, you only deprived your victim of a few moments of relaxation?  I don't think so.  It will be the same if we are "saved by the bell" from the consequences of our own foolish decisions.  But we must also prepare for the possibility that we are here for the long haul, in which case the problem becomes all the more urgent.  Lord have mercy!