hn-classics/_stories/1998/13315746.md

---
created_at: '2017-01-04T04:44:15.000Z'
title: Why anything? Why this? (1998)
url: http://www.lrb.co.uk/v20/n02/derek-parfit/why-anything-why-this
author: diodorus
points: 66
story_text: 
comment_text: 
num_comments: 77
story_id: 
story_title: 
story_url: 
parent_id: 
created_at_i: 1483505055
_tags:
- story
- author_diodorus
- story_13315746
objectID: '13315746'
year: 1998

---
Why does the Universe exist? There are two questions here. First, why is
there a Universe at all? It might have been true that nothing ever
existed: no living beings, no stars, no atoms, not even space or time.
When we think about this possibility, it can seem astonishing that
anything exists. Second, why does this Universe exist? Things might have
been, in countless ways, different. So why is the Universe as it is?

These questions, some believe, may have causal answers. Suppose first
that the Universe has always existed. Some believe that, if all events
were caused by earlier events, everything would be explained. That,
however, is not so. Even an infinite series of events cannot explain
itself. We could ask why this series occurred, rather than some other
series, or no series. Of the supporters of the Steady State Theory, some
welcomed what they took to be this theory’s atheistic implications. They
assumed that, if the Universe had no beginning, there would be nothing
for a Creator to explain. But there would still be an eternal Universe
to explain.

Suppose next that the Universe is not eternal, since nothing preceded
the Big Bang. That first event, some physicists suggest, may have obeyed
the laws of quantum mechanics, by being a random fluctuation in a
vacuum. This would causally explain, they say, how the Universe came
into existence out of nothing. But what physicists call a vacuum isn’t
really nothing. We can ask why it exists, and has the potentialities it
does. In Hawking’s phrase, ‘What breathes fire into the equations?’

Similar remarks apply to all suggestions of these kinds. There could not
be a causal explanation of why the Universe exists, why there are any
laws of nature, or why these laws are as they are. Nor would it make a
difference if there is a God, who caused the rest of the Universe to
exist. There could not be a causal explanation of why God exists.

Many people have assumed that, since these questions cannot have causal
answers, they cannot have any answers. Some therefore dismiss these
questions, thinking them not worth considering. Others conclude that
they do not make sense. They assume that, as Wittgenstein wrote, ‘doubt
can exist only where there is a question; and a question only where
there is an answer.’

These assumptions are all, I believe, mistaken. Even if these questions
could not have answers, they would still make sense, and they would
still be worth considering. I am reminded here of the aesthetic category
of the sublime, as applied to the highest mountains, raging oceans, the
night sky, the interiors of some cathedrals, and other things that are
superhuman, awesome, limitless. No question is more sublime than why
there is a Universe: why there is anything rather than nothing. Nor
should we assume that answers to this question must be causal. And, even
if reality cannot be fully explained, we may still make progress, since
what is inexplicable may become less baffling than it now seems.

One apparent fact about reality has recently been much discussed. Many
physicists believe that, for life to be possible, various features of
the Universe must be almost precisely as they are. As one example, we
can take the initial conditions in the Big Bang. If these conditions had
been more than very slightly different, these physicists claim, the
Universe would not have had the complexity that allows living beings to
exist. Why were these conditions so precisely
right?[\[\*\]](#fn-asterisk)

Some say: ‘If they had not been right, we couldn’t even ask this
question.’ But that is no answer. It could be baffling how we survived
some crash even though, if we hadn’t, we could not be baffled.

Others say: ‘There had to be some initial conditions, and the conditions
that make life possible were as likely as any others. So there is
nothing to be explained.’ To see what is wrong with this reply, we must
distinguish two kinds of case. Suppose first that, when some radio
telescope is aimed at most points in space, it records a random sequence
of incoming waves. There might be nothing here that needed to be
explained. Suppose next that, when the telescope is aimed in one
direction, it records a sequence of waves whose pulses match the number
π, in binary notation, to the first ten thousand digits. That
particular number is, in one sense, just as likely as any other. But
there would be something here that needed to be explained. Though each
long number is unique, only a very few are, like π, mathematically
special. What would need to be explained is why this sequence of waves
exactly matched such a special number. Though this matching might be a
coincidence, which had been randomly produced, that would be most
unlikely. We could be almost certain that these waves had been produced
by some kind of intelligence.

On the view that we are now considering, since any sequence of waves is
as likely as any other, there would be nothing to be explained. If we
accepted this view, intelligent beings elsewhere in space would not be
able to communicate with us, since we would ignore their messages. Nor
could God reveal himself. Suppose that, with an optical telescope, we
saw a distant pattern of stars which spelled out in Hebrew script the
first chapter of Genesis. According to this view, this pattern of stars
would not need to be explained. That is clearly false.

Here is another analogy. Suppose first that, of a thousand people facing
death, only one can be rescued. If there is a lottery to pick this one
survivor, and I win, I would be very lucky. But there might be nothing
here that needed to be explained. Someone had to win, and why not me?
Consider next another lottery. Unless my gaoler picks the longest of a
thousand straws, I shall be shot. If my gaoler picks that straw, there
would be something to be explained. It would not be enough to say, ‘This
result was as likely as any other.’ In the first lottery, nothing
special happened: whatever the result, someone’s life would be saved. In
this second lottery, the result was special, since, of the thousand
possible results, only one would save a life. Why was this special
result also what happened? Though this might be a coincidence, the
chance of that is only one in a thousand. I could be almost certain
that, like Dostoevsky’s mock execution, this lottery was rigged.

The Big Bang, it seems, was like this second lottery. For life to be
possible, the initial conditions had to be selected with great accuracy.
This appearance of fine-tuning, as some call it, also needs to be
explained.

It may be objected that, in regarding conditions as special if they
allow for life, we unjustifiably assume our own importance. But life is
special, if only because of its complexity. An earthworm’s brain is more
complicated than a lifeless galaxy. Nor is it only life that requires
this fine-tuning. If the Big Bang’s initial conditions had not been
almost precisely as they were, the Universe would have either almost
instantly recollapsed, or expanded so fast, and with particles so thinly
spread, that not even stars or heavy elements could have formed. That is
enough to make these conditions very special.

It may next be objected that these conditions cannot be claimed to be
improbable, since such a claim requires a statistical basis, and there
is only one Universe. If we were considering all conceivable Universes,
it would indeed be implausible to make judgments of statistical
probability. But our question is much narrower. We are asking what would
have happened if, with the same laws of nature, the initial conditions
had been different. That provides the basis for a statistical judgment.
There is a range of values that these conditions might have had, and
physicists can work out in what proportion of this range the resulting
Universe could have contained stars, heavy elements and life.

This proportion, it is claimed, is extremely small. Of the range of
possible initial conditions, fewer than one in a billion billion would
have produced a Universe with the complexity that allows for life. If
this claim is true, as I shall here assume, there is something that
cries out to be explained. Why was one of this tiny set also the one
that actually obtained?

On one view, this was a mere coincidence. That is conceivable, since
coincidences happen. But this view is hard to believe, since, if it were
true, the chance of this coincidence occurring would be below one in a
billion billion.

Others say: ‘The Big Bang was fine-tuned. In creating the Universe, God
chose to make life possible.’ Atheists may reject this answer, thinking
it improbable that God exists. But this probability cannot be as low as
one in a billion billion. So even atheists should admit that, of these
two answers to our question, the one that invokes God is more likely to
be true.

This reasoning revives one of the traditional arguments for belief in
God. In its strongest form, this argument appealed to the many features
of animals, such as eyes or wings, that look as if they have been
designed. Paley’s appeal to such features much impressed Darwin when he
was young. Darwin later undermined this form of the argument, since
evolution can explain this appearance of design. But evolution cannot
explain the appearance of fine-tuning in the Big Bang.

This argument’s appeal to probabilities can be challenged in a different
way. In claiming it to be most improbable that this fine-tuning was a
coincidence, the argument assumes that, of the possible initial
conditions in the Big Bang, each was equally likely to obtain. That
assumption may be mistaken. The conditions that allow for complexity and
life may have been, compared with all the others, much more likely to
obtain. Perhaps they were even certain to obtain.

To answer this objection, we must broaden this argument’s conclusion. If
these life-allowing conditions were either very likely or certain to
obtain, then – as the argument claims – it would be no coincidence that
the Universe allows for complexity and life. But this fine-tuning might
have been the work, not of some existing being, but of some impersonal
force, or fundamental law. That is what some theists believe God to be.

A stronger challenge to this argument comes from a different way of
explaining the appearance of fine-tuning. Consider first a similar
question. For life to be possible on Earth, many of Earth’s features
have to be close to being as they are. The Earth’s having such features,
it might be claimed, is unlikely to be a coincidence, and should
therefore be regarded as God’s work. But such an argument would be weak.
The Universe, we can reasonably believe, contains many planets, with
varying conditions. We should expect that, on a few of these planets,
conditions would be just right for life. Nor is it surprising that we
live on one of these few.

Things are different, we may assume, with the appearance of fine-tuning
in the Big Bang. While there are likely to be many other planets, there
is only one Universe. But this difference may be less than it seems.
Some physicists suggest that the observable Universe is only one out of
many different worlds, which are all equally parts of reality. According
to one such view, the other worlds are related to ours in a way that
solves some of the mysteries of quantum physics. On the different and
simpler view that is relevant here, the other worlds have the same
fundamental laws of nature as our world, and they are produced by Big
Bangs that are broadly similar, except in having different initial
conditions.

On this Many Worlds Hypothesis, there is no need for fine-tuning. If
there were enough Big Bangs, we should expect that, in a few of them,
conditions would be just right to allow for complexity and life; and it
would be no surprise that our Big Bang was one of these few. To
illustrate this point, we can revise my second lottery. Suppose my
gaoler picks a straw, not once but many times. That would explain his
managing, once, to pick the longest straw, without that’s being an
extreme coincidence, or this lottery’s being rigged.

On most versions of the Many Worlds Hypothesis, these many worlds are
not, except through their origins, causally related. Some object that,
since our world could not be causally affected by such other worlds, we
can have no evidence for their existence, and can therefore have no
reason to believe in them. But we do have such a reason, since their
existence would explain an otherwise puzzling feature of our world: the
appearance of fine-tuning.

Of these two ways to explain this appearance, which is better? Compared
with belief in God, the Many Worlds Hypothesis is more cautious, since
its claim is merely that there is more of the kind of reality that we
can observe around us. But God’s existence has been claimed to be
intrinsically more probable. According to most theists, God is a being
who is omnipotent, omniscient and wholly good. The uncaused existence of
such a being has been claimed to be simpler, and less arbitrary, than
the uncaused existence of many highly complicated worlds. And simpler
hypotheses, many scientists assume, are more likely to be true.

If such a God exists, however, other features of our world become hard
to explain. It may not be surprising that God chose to make life
possible. But the laws of nature could have been different, so there are
many possible worlds that would have contained life. It is hard to
understand why, out of all these possibilities, God chose to create our
world. What is most baffling is the problem of evil. There appears to be
suffering which any good person, knowing the truth, would have prevented
if he could. If there is such suffering, there cannot be a God who is
omnipotent, omniscient and wholly good.

To this problem, theists have proposed several solutions. Some suggest
that God is not omnipotent, or not wholly good. Others suggest that
undeserved suffering is not, as it seems, bad, or that God could not
prevent such suffering without making the Universe, as a whole, less
good.

We must ignore these suggestions here, since we have larger questions to
consider. I began by asking why things are as they are. Before returning
to that question, we should ask how things are. There is much about our
world that we have not discovered. And, just as there may be other
worlds that are like ours, there may be worlds that are very different.

It will help to distinguish two kinds of possibility. Cosmic
possibilities cover everything that ever exists, and are the different
ways that the whole of reality might be. Only one such possibility can
be actual, or the one that obtains. Local possibilities are the
different ways that some part of reality, or local world, might be. If
some local world exists, that leaves it open whether other worlds exist.

One cosmic possibility is, roughly, that every possible local world
exists. This we can call the All Worlds Hypothesis. Another possibility,
which might have obtained, is that nothing ever exists. This we can call
the Null Possibility. In each of the remaining possibilities, the number
of worlds that exist is between none and all. There are countless of
these possibilities, since there are countless combinations of
particular possible local worlds.

Of these different cosmic possibilities, one must obtain, and only one
can obtain. So we have two questions: which obtains, and why? These
questions are connected. If some possibility would be easier to explain,
we have more reason to believe that this possibility obtains. This is
how, rather than believing in only one Big Bang, we have more reason to
believe in many. Whether we believe in one or many, we have the question
why any Big Bang has occurred. Though this question is hard, the
occurrence of many Big Bangs is not more puzzling than the occurrence of
only one. Most kinds of thing, or event, have many instances. We also
have the question why, in the Big Bang that produced our world, the
initial conditions allowed for complexity and life. If there has been
only one Big Bang, this fact is also hard to explain, since it is most
unlikely that these conditions merely happened to be right. If, instead,
there have been many Big Bangs, this fact is easy to explain, since it
is like the fact that, among countless planets, there are some whose
conditions allow for life. Since belief in many Big Bangs leaves less
that is unexplained, it is the better view.

If some cosmic possibilities would be less puzzling than others, because
their obtaining would leave less to be explained, is there some
possibility whose obtaining would be in no way puzzling?

Consider first the Null Possibility, in which nothing ever exists. To
imagine this possibility, it may help to suppose first, that all that
ever existed was a single atom. We then imagine that even this atom
never existed.

Some have claimed that, if there had never been anything, there wouldn’t
have been anything to be explained. But that is not so. When we imagine
how things would have been if nothing had ever existed, what we should
imagine away are such things as living beings, stars and atoms. There
would still have been various truths, such as the truth that there were
no stars or atoms, or that 9 is divisible by 3. We can ask why these
things would have been true. And such questions may have answers. Thus
we can explain why, even if nothing had ever existed, 9 would still have
been divisible by 3. There is no conceivable alternative. And we can
explain why there would have been no such things as immaterial matter,
or spherical cubes. Such things are logically impossible. But why would
nothing have existed? Why would there have been no stars or atoms, no
philosophers or bluebell woods?

We should not claim that, if nothing had ever existed, there would have
been nothing to be explained. But we can claim something less. Of all
the global possibilities, the Null Possibility would have needed the
least explanation. As Leibniz pointed out, it is much the simplest, and
the least arbitrary. And it is the easiest to understand. It can seem
mysterious, for example, how things could exist without their existence
having some cause, but there cannot be a causal explanation of why the
whole Universe, or God, exists. The Null Possibility raises no such
problem. If nothing had ever existed, that state of affairs would not
have needed to be caused.

Reality, however, does not take its least puzzling form. In some way or
other, a Universe has managed to exist. That is what can take one’s
breath away. As Wittgenstein wrote, ‘not how the world is, is the
mystical, but that it is.’ Or, in the words of a thinker as unmystical
as Jack Smart: ‘That anything should exist at all does seem to me a
matter for the deepest awe.’

Consider next the All Worlds Hypothesis, in which every possible local
world exists. Unlike the Null Possibility, this may be how things are.
And it may be the next least puzzling possibility. This hypothesis is
not the same as – though it includes – the Many Worlds Hypothesis. On
that more cautious view, many other worlds have the same elements as our
world, and the same fundamental laws, and differ only in such features
as their constants and initial conditions. The All Worlds Hypothesis
covers every conceivable kind of world, and most of these other worlds
would have very different elements and laws.

If all these worlds exist, we can ask why they do. But, compared with
most other cosmic possibilities, the All Worlds Hypothesis may leave
less that is unexplained. For example, whatever the number of possible
worlds that exist, we have the question, ‘Why that number?’ This
question would have been least puzzling if the number that existed were
none, and the next least arbitrary possibility seems to be that all
these worlds exist. With every other cosmic possibility, we have a
further question. If ours is the only world, we can ask: ‘Out of all the
possible worlds, why is this the one that exists?’ On any version of the
Many Worlds Hypothesis, we have a similar question: ‘Why do just these
worlds exist, with these elements and laws?’ But, if all these worlds
exist, there is no such further question.

It may be objected that, even if all possible local worlds exist, that
does not explain why our world is as it is. But that is a mistake. If
all these worlds exist, each world is as it is in the way in which each
number is as it is. We cannot sensibly ask why 9 is 9. Nor should we ask
why our world is the one it is: why it is this world. That would be like
asking, ‘Why are we who we are?’, or ‘Why is it now the time that it
is?’ Those are not good questions.

Though the All Worlds Hypothesis avoids certain questions, it is not as
simple, or un-arbitrary, as the Null Possibility. There may be no sharp
distinction between worlds that are and are not possible. It is unclear
what counts as a kind of world. And, if there are infinitely many kinds,
there is a choice between different kinds of infinity.

Whichever cosmic possibility obtains, we can ask why it obtains. All
that I have claimed so far is that, with some possibilities, this
question would be less puzzling. Let us now ask: could this question
have an answer? Might there be a theory that leaves nothing unexplained?

It is sometimes claimed that God, or the Universe, make themselves
exist. But this cannot be true, since these entities cannot do anything
unless they exist.

On a more intelligible view, it is logically necessary that God, or the
Universe, exist, since the claim that they might not have existed leads
to a contradiction. On such a view, though it may seem conceivable that
there might never have been anything, that is not really logically
possible. Some people even claim that there may be only one coherent
cosmic possibility. Thus Einstein suggested that, if God created our
world, he might have had no choice about which world to create. If such
a view were true, everything might be explained. Reality might be the
way it is because there was no conceivable alternative. But, for reasons
that have been often given, we can reject such views.

Consider next a quite different view. According to Plato, Plotinus and
others, the Universe exists because its existence is good. Even if we
are confident that we should reject this view, it is worth asking
whether it makes sense. If it does, that may suggest other
possibilities.

This Axiarchic View can take a theistic form. It can claim that God
exists because his existence is good, and that the rest of the Universe
exists because God caused it to exist. But in that explanation God, qua
Creator, is redundant. If God can exist because his existence is good,
so can the whole Universe. This may be why some theists reject the
Axiarchic View, and insist that God’s existence is a brute fact, with no
explanation.

In its simplest form, this view makes three claims: ‘(1) It would be
best if reality were a certain way. (2) Reality is that way. (3) (1)
explains (2).’ (1) is an ordinary evaluative claim, like the claim that
it would be better if there was less suffering. The Axiarchic View
assumes, I believe rightly, that such claims can be in a strong sense
true. (2) is an ordinary empirical or scientific claim, though of a
sweeping kind. What is distinctive in this view is claim (3), according
to which (1) explains (2).

Can we understand this third claim? To focus on this question, we should
briefly ignore the world’s evils, and suspend our other doubts about
claims (1) and (2). We should suppose that, as Leibniz claimed, the best
possible Universe exists. Would it then make sense to claim that this
Universe exists because it is the best?

That use of ‘because’, Axiarchists should admit, cannot be easily
explained. But even ordinary causation is mysterious. At the most
fundamental level, we have no idea why some events cause others; and it
is hard to explain what causation is. There are, moreover, non-causal
senses of ‘because’ and ‘why’, as in the claim that God exists because
his existence is logically necessary. We can understand that claim, even
if we think it false. The Axiarchic View is harder to understand. But
that is not surprising. If there is some explanation of the whole of
reality, we should not expect this explanation to fit neatly into some
familiar category. This extra-ordinary question may have an
extra-ordinary answer. We should reject suggested answers which make no
sense; but we should also try to see what might make sense.

Axiarchy might be expressed as follows. We are now supposing that, of
all the countless ways that the whole of reality might be, one is both
the very best, and is the way that reality is. On the Axiarchic View,
that is no coincidence. This claim, I believe, makes sense. And, if it
were no coincidence that the best way for reality to be is also the way
that reality is, that might support the further claim that this was why
reality was this way.

This view has one advantage over the more familiar theistic view. An
appeal to God cannot explain why the Universe exists, since God would
himself be part of the Universe, or one of the things that exist. Some
theists argue that, since nothing can exist without a cause, God, who is
the First Cause, must exist. As Schopenhauer objected, this argument’s
premise is not like some cabdriver whom theists are free to dismiss once
they have reached their destination. The Axiarchic View appeals, not to
an existing entity, but to an explanatory law. Since such a law would
not itself be part of the Universe, it might explain why the Universe
exists, and is as good as it could be. If such a law governed reality,
we could still ask why it did, or why the Axiarchic View was true. But,
in discovering this law, we would have made some progress.

It is hard, however, to believe the Axiarchic View. If, as it seems,
there is much pointless suffering, our world cannot be part of the best
possible Universe.

Some Axiarchists claim that, if we reject their view, we must regard our
world’s existence as a brute fact, since no other explanation could make
sense. But that, I believe, is not so. If we abstract from the optimism
of the Axiarchic View, its claims are these: ‘Of the countless cosmic
possibilities, one both has a very special feature, and is the
possibility that obtains. That is no coincidence. This possibility
obtains because it has this feature.’ Other views can make such claims.
This special feature need not be that of being best. Thus, on the All
Worlds Hypothesis, reality is maximal, or as full as it could be.
Similarly, if nothing had ever existed, reality would have been minimal,
or as empty as it could be. If the possibility that obtained were either
maximal or minimal, that fact, we might claim, would be most unlikely to
be a coincidence. And that might support the further claim that this
possibility’s having this feature would be why it obtained.

Let us now look more closely at that last step. When it is no
coincidence that two things are both true, there is something that
explains why, given the truth of one, the other is also true. The truth
of either might make the other true. Or both might be explained by some
third truth, as when two facts are the joint effects of a common cause.

Suppose next that, of the cosmic possibilities, one is both very special
and is the one that obtains. If that is no coincidence, what might
explain why these things are both true? On the reasoning that we are now
considering, the first truth explains the second, since this possibility
obtains because it has this special feature. Given the kind of truths
these are, such an explanation could not go the other way. This
possibility could not have this feature because it obtains. If some
possibility has some feature, it could not fail to have this feature, so
it would have this feature whether or not it obtains. The All Worlds
Hypothesis, for example, could not fail to describe the fullest way for
reality to be.

While it is necessary that our imagined possibility has its special
feature, it is not necessary that this possibility obtains. This
difference, I believe, justifies the reasoning that we are now
considering. Since this possibility must have this feature, but might
not have obtained, it cannot have this feature because it obtains, nor
could some third truth explain why it both has this feature and obtains.
So, if these facts are no coincidence, this possibility must obtain
because it has this feature.

When some possibility obtains because it has some feature, its having
this feature may be why some agent, or process of natural selection,
made it obtain. These we can call the intentional and evolutionary ways
in which some feature of some possibility may explain why it obtains.

Our world, theists claim, can be explained in the first of these ways.
If reality were as good as it could be, it would indeed make sense to
claim that this was partly God’s work. But, since God’s own existence
could not be God’s work, there could be no intentional explanation of
why the whole of reality was as good as it could be. So we could
reasonably conclude that this way’s being the best explained directly
why reality was this way. Even if God exists, the intentional
explanation could not compete with the different and bolder explanation
offered by the Axiarchic View.

Return now to other explanations of this kind. Consider first the Null
Possibility. This, we know, does not obtain; but, since we are asking
what makes sense, that does not matter. If there had never been
anything, would that have had to be a brute fact, which had no
explanation? The answer, I suggest, is No. It might have been no
coincidence that, of all the countless cosmic possibilities, what
obtained was the simplest, and least arbitrary, and the only possibility
in which nothing ever exists. And, if these facts had been no
coincidence, this possibility would have obtained because – or partly
because – it had one or more of these special features. This
explanation, moreover, could not have taken an intentional or
evolutionary form. If nothing had ever existed, there could not have
been some agent, or process of selection, who or which made this
possibility obtain. Its being the simplest or least arbitrary
possibility would have been, directly, why it obtained.

Consider next the All Worlds Hypothesis, which may obtain. If reality is
as full as it could be, is that a coincidence? Does it merely happen to
be true that, of all the cosmic possibilities, the one that obtains is
at this extreme? As before, that is conceivable, but this coincidence
would be too great to be credible. We can reasonably assume that, if
this possibility obtains, that is because it is maximal, or at this
extreme. On this Maximalist View, it is a fundamental truth that being
possible, and part of the fullest way that reality could be, is
sufficient for being actual. That is the highest law governing reality.
As before, if such a law governed reality, we could still ask why it
did. But, in discovering this law, we would have made some progress.

Here is another special feature. Perhaps reality is the way it is
because its fundamental laws are, on some criterion, as mathematically
beautiful as they could be. That is what some physicists are inclined to
believe.

As these remarks suggest, there is no clear boundary here between
philosophy and science. If there is such a highest law governing
reality, this law is of the same kind as those that physicists are
trying to discover. When we appeal to natural laws to explain some
features of reality, such as the relations between light, gravity, space
and time, we are not giving causal explanations, since we are not
claiming that one part of reality caused another part to be some way.
What such laws explain, or partly explain, are the deeper facts about
reality that causal explanations take for granted. In the second half of
this essay, I shall ask how deep such explanations could go.