I. Michael Behe and Biological Arguments
Irreducible
complexity –
By
irreducibly complex I mean a single
system composed of several well-matched, interacting parts that contribute to
the basic function, wherein the removal of any one of the parts causes the
system to effectively cease functioning.[1]
Alleged examples:[2]
(1) Bacterial
flagellum
(2) Cascade
of biochemical reactions and events that occur in vision
(3) Blood
clotting
(4) Transport
of materials within cells
(5) Immune
system
The significance of irreducible complexity is this:
An
irreducibly complex system cannot be produced directly (that is, by
continuously improving the initial function, which continues to work by the
same mechanism) by slight, successive modifications of a precursor system,
because any precursor to an irreducibly complex system that is missing a part
is by definition nonfunctional.[3]
Obviously
the various components of the eye must all work together to enable vision; so
all these different parts would have to evolve in tandem. But an improvement to
the lens (a step on the way to the present function of the lens) wouldn’t
automatically permit better vision, and in fact may interfere with it.
The problem, then, is to conceive of
a series of steps through “design space” where (1) the first point is occupied
by a design with no more than a light sensitive spot, as we find with certain
relatively primitive animals; (2) each point (except the first) represents a
design arising by way of heritable genetic variation (the main candidate is
random genetic mutation) from the previous point; (3) divine or other guidance
or causality is not involved in the transition from any point to the next; (4)
each point is an adaptive step forward with respect to the previous point, or
else a consequence, by way of spandrel or pliotropy,[5] of
a design that is such a step forward; (5) each point is not overwhelmingly
improbable with respect to the previous point; and (6) the last point is
occupied by (correlated with) the design of the human eye.[6]
Plantinga: [I]t
isn’t required that the Darwinist come up with the actual sequence of design
plans here, or a sequence which could have been the actual sequence; what is
required for a satisfying evolutionary account of the eye is perhaps more like
a reasonably detailed specification of some important stages along the way.[7]
Behe: There aren’t any Darwinian accounts of any of
these structures, and, by virtue of their irreducible complexity, there won’t be any; such accounts can’t
possibly be given.[8]
Q1: Do you think
Behe is warranted in his claim that some physical structures possessed by
organisms are irreducibly complex? Why or why not?
à
The alternative that Behe famously (or perhaps infamously) proposes to replace
Darwinism is Intelligent Design.
Q2: Do you think
Intelligent Design is a legitimate scientific theory? What criteria determine
whether or not a theory is legitimately scientific, and how does Intelligent
Design fare against these criteria?
Paul Draper:
(1) Behe
fails to show that the systems he says are irreducibly complex are in fact
irreducibly complex (that is, such that if they missed any of their parts, they
couldn’t function at all); some biochemists…have argued that they’re not.
(2) There
is also difficulty, here, about what constitutes a part: couldn’t some of these
systems function perfectly well in the absence of a molecule or two?
à
Draper: This response presupposes a
new definition of irreducible complexity, one that implies that a system is
irreducibly complex even if it has working parts that are not essential for it
to function, so long as it has (at least two) interacting and closely matched
parts which are essential. Given this definition, it would seem that the
biochemical systems Behe discusses are indeed irreducibly complex.[9]
(3) Even
if there aren’t any direct Darwinian routes to these systems, there may still
be various indirect routes to them.[10]
The
sort of route I have in mind occurs when an irreducibly complex and irreducibly
specific system S that serves function F evolves from a precursor S* that
shares many of S’s parts but serves a different function F*. Notice that the
parts that S and S* share and that are required for F need not be required for
F* even if they contribute to F*, and parts that are irreducibly specific
relative to F may be only reducibly specific relative to F*. Thus, both the
parts of S* and their specificity may have been gradually produced by a direct
evolutionary path. Then one or more additional parts are added to S*, resulting
in a change of function from F* to F. And relative to F, the parts and their
specificity, which had not been essential for F*, are now essential.[11]
Q3: How might
Behe respond to Draper’s objections?
à
Draper: I believe that Behe’s most
promising reply to these objections would be to admit the possibility of direct
routes to irreducible complexity, but claim that, like indirect routes, they
are very unlikely to produce the specific biochemical systems on which Behe
builds his case. Of course, it would not be enough for Behe simply to claim that direct routes to these
systems are very unlikely; he would need to argue for that claim. And it is an
open question whether or not a good argument is available.[13]
[Behe’s 2007 book The
Edge of Evolution] argues that there
are structures at the molecular level of life that could not have been produced
by (unguided) natural selection[, e.g.,
the elaborately complex protein machines of the cell.][14]
Plantinga describes this work as “one of the few serious and quantitative
arguments in this area.”[15]
[I]f
it takes 1020 organisms to develop one new protein-interaction site,
then a mutation issuing in two new (simultaneous) protein-protein interaction
sites will require 1040 organisms. Estimates of the total number of
organisms that have so far come to be in the history of Earth put that lumber
at less than 1040. But then, so the thinking goes, it will be
improbable that unguided natural selection should produce three protein-protein
interaction sites in the history of the earth, and enormously improbable that
it should produce the large protein machines involving assemblies of 10 or more
proteins of which Alberts speaks.[16]
Q4: Granting that
the ordinary physiology of the average organism fails to provide adequate
conditions for making the necessary evolutionary advances not prohibitively
improbable (in this case, the development of new protein interaction sites), might
there not be other factors, whether biotic or abiotic, that serve to influence
this rate such that the necessary advances are made more probable? Doesn’t the
punctuated equilibrium thesis suggest something like this might be the case? If
so, what factors might serve such a function?
Punctuated
Equilibrium[17]
–
Punctuated equilibrium
(also called punctuated equilibria) is a theory in evolutionary biology which
proposes that once formed most species
will exhibit little net evolutionary change for most of their geological
history, remaining in an extended state of stasis. When significant
evolutionary change occurs, the theory proposes that it is generally restricted
to rare and rapid (on a geologic time scale)
events of branching speciation called cladogenesis. Cladogenesis
is the process by which a species splits into two distinct species, rather than
one species gradually transforming into another. Punctuated equilibrium is
commonly contrasted against phyletic gradualism,
the belief that evolution generally occurs uniformly and by the steady and
gradual transformation of whole lineages (called anagenesis). In this view,
evolution is seen as generally smooth and continuous.
In
1972, paleontologists Niles Eldredge
and Stephen Jay
Gould published a landmark paper developing their theory and called
it punctuated equilibria. Their paper built upon Ernst Mayr's model of geographic
speciation, I. Michael
Lerner's theories of developmental and genetic homeostasis, as well
as their own empirical
research. Eldredge and Gould proposed that the degree of gradualism
commonly attributed to Charles
Darwin is virtually nonexistent in the fossil record, and that
stasis dominates the history of most fossil species.
Cambrian Explosion[18]
–
The
Cambrian
explosion was the relatively rapid appearance around 542 million years ago of most
major animal phyla as demonstrated in
the fossil record, and many more phyla now extinct. This was accompanied by
major diversification of other organisms. Prior to the Cambrian explosion most
organisms were simple, composed of individual cells occasionally organized into
colonies. Over
the following 70 or 80 million years, the rate of diversification accelerated
by an order of
magnitude and the diversity of life began to resemble that of today,
although they did not resemble the species of today.
The
basic problem with this is that natural selection calls for the slow
accumulation of changes, where a new phyla would take longer than a new class
which would take longer than a new order, which would take longer than a new
family, which would take longer than a new genus would take longer than
emergence of a new species but the apparent occurrence of high-level taxa
without precedents is perhaps implying unusual evolutionary mechanisms.
There
is general consensus that many factors helped trigger the Cambrian explosion,
but there is no generally accepted consensus about the combination and the
Cambrian explosion continues to be an area of controversy and research over why
so rapid, why at the phylum level, why so many phyla then and none since, and
even if the apparent fossil record is accurate.
An
example of opinions involving the commonly cited rise in oxygen Great
Oxidation Event from biologist PZ Myers summarizes: "What
it was was environmental changes, in particular the bioturbation revolution
caused by the evolution of worms that released buried nutrients, and the
steadily increasing oxygen
content of the atmosphere that allowed those nutrients to fuel growth;
ecological competition, or a kind of arms race, that gave a distinct selective
advantage to novelties that allowed species to occupy new niches; and the
evolution of developmental mechanisms that enabled multicellular organisms to
generate new morphotypes readily." The increase in molecular oxygen (O2)
also may have allowed the formation of the protective ozone layer (O3)
that helps shield Earth from lethal UV radiation from the Sun.
Q5: Behe sets the
“edge of evolution” at the level of orders, families, and genera; unguided
evolution, he thinks, could produce new species.[19]
What do you think he considers special about this boundary that Behe decides to
set his boundary here?
Objection 1:
Behe’s sample may be biased; P.
falciparum [the Malaria parasite] and the HIV virus involve host-parasite
interaction, and perhaps what holds for host-parasite interaction doesn’t hold
generally.[20]
à
Although some have argued that host-parasite interactions might actually accelerate evolutionary processes by
setting up an arms race of sorts in which each organism is forced to adapt to keep
up with the constant pressure imposed by the other, just as in certain
predator-prey relationships.[21]
Red Queen Hypothesis
–
The
Red Queen hypothesis, also referred to as Red Queen's, Red Queen's race or The
Red Queen Effect, is an evolutionary
hypothesis which proposes
that organisms must constantly adapt, evolve, and proliferate not merely to
gain reproductive advantage, but also simply to survive while pitted against
ever-evolving opposing organisms
in an ever-changing environment. The Red Queen hypothesis intends to explain
two different phenomena: the constant extinction rates as observed in the
paleontological record caused by co-evolution between competing species and the
advantage of sexual reproduction (as opposed to asexual reproduction) at the
level of individuals.
The
original idea of the Red Queen hypothesis was given by Leigh Van Valen in order
to explain the "Law of Extinction". Leigh Van Valen showed that in
many populations the probability of extinction does not depend on the lifetime
of this population. In addition, the probability of extinction is constant over
millions of years for a given population. This could be explained by the coevolution of species.
Indeed, an adaptation
in a population of one species (e.g. predators, parasites) may change the
selection pressure on a population of another species (e.g. prey, hosts), giving rise to an
antagonistic coevolution. If this occurs reciprocally, a
potential dynamic coevolution may result.
The
Red Queen at the genus level. The linear relationship between number of genera
and the logarithm of survival times suggests that the probability of extinction
is constant over time. Redrawn from Leigh Van Valen (1973).
In
another idea, the Red Queen hypothesis is used independently by Hartung and
Bell to explain the evolution of sex, by John Jaenike to explain the
maintenance of sex and W. D. Hamilton to explain the role of sex in response to
parasites. In all cases, sexual reproduction
confers species variability and a faster generational response to selection by making
offspring genetically unique. Sexual species are able to improve their genotype
in changing conditions. Consequently co-evolutionary interactions, between host
and parasite for example, may select for sexual reproduction in hosts in order
to reduce the risk of infection. Oscillations in genotype
frequencies are observed between parasites and hosts in an
antagonistic coevolutionary way[8] without necessitating changes to the
phenotype.[22]
Objection 2: [W]here
two or more protein-protein interaction sites are required, perhaps one of
these appears, and is in some way adaptive, so that it persists until the other
appears also.[23]
Q6: How might
Behe respond to the objections above?
à
Plantinga: It’s too difficult to
calculate the relevant possibilities so as to build an argument for God on
Behe’s premises.[24]
Behe: I strongly emphasize that it is
not an argument for the existence of a benevolent God…This, while I argue for
design, the question of the identity of the designer is left open. Possible
candidates for the role of designer include: the God of Christianity; an
angel-fallen or not; Plato’s demiurge; some mystical new-age force; space
aliens from Alpha Centauri; time travelers; or some utterly unknown intelligent
being.[25]
Q7: What kind of
constraints might be reasonable to put on Behe’s designer? Assuming we do have
a designer, it seems that he/she/it would also have a natural history, i.e., an
explanation for how he/she/it came to be. Does Behe imagine that there might be
alternative natural historical accounts for beings capable of designing
intelligent life that are less improbable than the Darwinian one? What might
such an account be? If our designer did have such a natural history, shouldn’t
we expect him/her/it to have employed those same processes to create life in
the present case, or a process at least as simple or efficient? Isn’t the only
way to avoid the difficulty posed by irreducible complexity to posit a designer
that does not him-/her-/it- self have a natural history, and doesn’t that leave
only an eternal being (God) on the table? Would that fact make his theory any less
attractive?
Q8: Is Behe’s
designer intended to be a creator or simply a guider of evolutionary processes?
Does it make any difference with respect to the type of designer needed to fit
the data?
II. Perceiving
Design
Plantinga:
Perhaps [Behe-style arguments,] as well as the fine-tuning arguments of the
last chapter, can be better thought of as like what is going on [in the
mountain goat case], where it is perception
(or something like it) rather than argument that is involved.[26]
Ways to interpret the teleological argument:
(1) Argument
from analogy (Hume)
(2) Inductive
argument
(3) Inference
to the best explanation
(1) Some
natural systems (e.g., the human eye) are mechanically ordered (i.e., they
exhibit the same sort of order as watches and other machines produced by human
beings).
(2) Intelligent
design is a very good explanation of mechanical order.
(3) No
other explanation (or no equally good explanation) of mechanical order is
available.
(4) Every
instance of mechanical order has an explanation.
(5) So,
some natural systems were (probably) designed.
Q9: Of the above
options, what do you think the most natural interpretation of Behe’s argument
is? Which interpretation do you think lends the strongest support to theism?
III. Design Argument
vs. Design Discourse
Plantinga: I
don’t ordinarily form any belief (any explicit belief, anyway) at all as to how
Paul is looking: I move directly to the view that he is furious…If we did [form
such beliefs on the basis of an inference, they] would not be well-founded and
would certainly not constitute knowledge.[29]
Small
children apparently form beliefs about the mental states of their parents long
before they come to the age at which they make inductive inferences. The
capacity for this sort of belief formation is not something one gains by
inductive learning; it is instead part of our native cognitive equipment. We
might put it by saying that we form beliefs of this sort in the basic way, not
on the evidential basis of other beliefs, other propositions we believe. That
is to say, we don’t form these beliefs on the basis of inference. It is rather
that we are hard-wired, as they say, to form these beliefs in certain
experiential circumstances.[30]
Types of belief formed in this way[31]
(1) Beliefs
about other minds
(2) Beliefs
about the past (memory)
(3) Perceptual
beliefs
Plantinga: Indeed,
it is exceedingly hard to see how I could
acquire the thought that there are past events by way of argument. What would
be the premises? The same goes for perception…[32]
Q10: What does it
mean to form beliefs in the basic way? How is the way that beliefs are formed
relevant to how much warrant or positive epistemic status it has?
Plantinga: How we form these beliefs is
important along several different dimensions, but it is particularly relevant
to the question how much warrant, or justification, or positive epistemic
status the beliefs in question have. Based on a tenuous analogical inference of
a speculative explanatory conjecture, these beliefs wouldn’t have anything like
the degree of warrant or positive epistemic status they actually do have; this
basis wouldn’t warrant anything like the degree of confidence we actually invest
in them…On the other hand, if they are formed in the basic way, then they might
very well constitute knowledge. For suppose (as it seems to be true) that a
belief B has warrant, that property
or quantity enough of which is what distinguishes mere true belief from
knowledge, just if B is formed b cognitive faculties functioning properly in
the sort of environment for which we were designed (by God or evolution)
according to a design plan successfully aimed at the production of true
beliefs…This sort of belief formation is not a result of movement from one set
of beliefs (premises) to another (conclusion), but from a set of circumstances
(being appeared to a certain way, for example) to a belief.[33]
Q11: How can we
tell if we are exercising our faculties in the appropriate environment
(context) so as to achieve warrant
for our beliefs? Why think that the perception of design in nature isn’t an
instance of a false positive delivered by faculties whose “proper design” was
to detect design in the ordinary cases, i.e., for authentic manufactured objects?
The same consideration would apply to detecting agency (God) in natural
processes or the transpiring of historical events.
Plantinga: So
what is [Paley] doing?
à
At least two things: Sometimes he is calling our attention to the sorts of
beliefs we do in fact find ourselves forming, or inclined to form…Other times
what he seems to be doing can perhaps be described as putting us in the sorts
of situations in which design beliefs are in fact formed…[H]e is trying to get
us to recall design beliefs, and put us in situations in which we form design
beliefs.[34]
Plantinga: Insofar
as design entails mental states on the part of some other person (the designer)
the belief that a given object has been designed is a mental state ascribing belief.[36]
IV. The Difference it Makes
Plantinga: What’s
the significance?
[T]he
suggestion is that you can come to form design beliefs, at least on some
occasions, in the basic way. If so, the belief in question can have warrant or
positive epistemic status for you, even if you don’t know of any good argument
from other beliefs for the belief in question – even, indeed, if there aren’t any good arguments of that sort.
As we’ve seen, this is how it goes with out beliefs about the mental states of
others; but the same goes for our perceptual beliefs. The same also goes for
our beliefs about the past…[37]
Secondly,
there is a difference here in the way in which the beliefs in question can be
criticized, or refuted. Beliefs formed in the basic way are not, of course,
immune to criticism…A belief formed on the basis of an argument, however, can
be criticized in a different way as well. When you (properly) form a belief on
the basis of an argument, what typically happens is that warrant or positive
epistemic status is transferred from the premise belief(s) to the conclusion…A
belief formed in that way, as the conclusion of an argument, can be criticized
in terms of the cogency of the argument. We can ask whether the argument is
valid, i.e., whether the conclusion really follows from the premises; we can
also ask whether the premises are true; we can also ask whether the argument is
circular, or begs the question, or is in some other way dialectically
deficient. None of these sorts of criticism is relevant to beliefs formed in
the basic way.[38]
In summary, beliefs acquired via argumentation (inference)
are evaluable on the basis of the cogency of the arguments supporting them, while
beliefs formed in the basic way are only evaluable on the basis of
meta-criteria like:
(1) Whether
they were formed with a particular type of faculty (namely, one that was
designed to track truth);
(2) The
health of that faculty (whether it is functioning as designed); and
(3) Whether
they were formed within the appropriate kind of environment
Q12: Do you agree
with Plantinga that beliefs formed in the basic way enjoy more warrant than
beliefs formed upon inference? Why or why not?
Q13: Do you think
that Plantinga sets the threshold for defeat in the appropriate place for
beliefs formed in the basic way? Do you think the same criteria can/should
apply to all beliefs formed in the
basic way, regardless of the belief type? Do you think the threshold for defeat
should be the same for all beliefs formed in the basic way as well, i.e., both to
beliefs about the past (beliefs produced by memory) as well as beliefs about design,
etc.? Why or why not?
Plantinga: How
can a design discourse be unsuccessful?
[O]ne
way would be to show, somehow, that the design discourse fails to produce any
tendency to form the relevant design belief. But there is also another way. A
basic belief can be subject to defeaters: one way, therefore to argue that a design
discourse is unsuccessful would be to show that the design belief formed in
this way is in fact subject to defeat. This would be a matter of producing a
defeater for the design belief – that is, getting a person who holds a certain
design belief to accept another belief D such that she can’t sensibly continue
to hold the design belief, as long as she holds the defeating belief D.[39]
On
the other hand, you might become convinced that as a matter of fact the eye was
not designed, but came to be in some other way. Then you would have a rebutting defeater: you come to believe
a proposition that you see is incompatible with the proposed defeatee.[40]
On
the other hand, I might acquire an undercutting
defeater. This would happen, roughly, if I come to believe something that
undercuts or nullifies or negates my reason for the proposed belief.[41]
Q14: Do you think
Plantinga’s criteria for failing a design discourse are fair or reasonable? Why
or why not?
Plantinga says that Darwin is often credited with having refuted
Paley’s argument.
Some
writers seem to believe that Darwin, or current evolutionary science, has
provided a rebutting defeater: they believe that evolutionary science has shown
that as a matter of fact eyes and other biological structures have not, in
point of sober truth, been designed.[42]
Plantinga: Even
if (contrary to fact) either Darwin or more recent biology were to have
actually shown that the biological structures in question have came to be by way of these Darwinian mechanisms, it wouldn’t follow
that they have not been designed; therefore they do not provide a rebutting
defeater for Paley’s design beliefs or a problem for Paley’s design discourse.
To provide a rebutting defeater here, Darwinian science would have to show that
the biological phenomena in question have been produced by unguided Darwinian evolution. But (naturally enough) they haven’t
shown that evolution is unguided by God or any other intelligent agent; that
wouldn’t be the sort of thing, one supposes, within the capability or empirical
science.[43]
Q15: Do you agree
with Plantinga that Darwinian considerations fail to provide a rebutting
defeater for design hypotheses? Why or why not?
Plantinga: Does
Darwinian evolution provide an undercutting
defeater for the design belief?
à
What the Darwinian has to show, to provide a defeater is an unguided
evolutionary path which is not prohibitively improbable.[44]
à Plantinga: The sensible thing to think,
here, is that we have a partial
undercutting defeater for those beliefs (formed in that way)…Evolutionary
biologists present considerations designed to show how it could be that these
structures have arisen by way of unguided Darwinian processes; they give us
some reason to believe that this is possible. These considerations, when you first
become aware of them, should somewhat
reduce your confidence that these structures have been designed.[45]
Q16: Do you agree
with Plantinga that Darwinian considerations fail to provide more than a
partial undercutting defeater for design hypotheses? Why or why not?
Plantinga: What
overall conclusion should be draw about these design discourses?
à
[W]e have partial defeaters for the design discourses at the level of gross
anatomy; we have partial defeaters for design beliefs having to do with the
eye, with the structures of limbs, and the like. We don’t have any such
defeaters for Behe design beliefs at the molecular and cellular level.[46]
Defeater – A
defeater D for a belief B is another belief I acquire, such that as long as I
hold that belief D, I cannot rationally (given my noetic structure) continue to
believe B (and a partial defeater requires that I hold B less firmly).[47]
Deflector 1 – A belief deflector D* for a
(potential) belief B, is, roughly speaking, a belief I already hold such that
as long as I hold it (and given my noetic structure) I can’t rationally
continue to hold B.[48]
Deflector 2 – A deflector
belief D for a (potential) belief B, is, roughly speaking, a belief I already
hold such that as long as I hold it (and given my noetic structure) I can’t
rationally continue to hold B AND in which belief B is such that in the
relevant circumstances, if D were not present in my noetic structure, I would
have formed B.[49]
Plantinga: Do
Darwinian considerations present a defeater for the design beliefs S forms in
response to a given design discourse?
à
It depends on who we’re talking about and several other factors.
(1) Theist
–
What
happens depends on the strength of S’s theistic belief, and also on the
strength of her reaction to the potential Darwinian defeating belief. If the
Darwinian considerations produce a strong enough impulse to form the belief
that the phenomena in question are not
designed, if that impulse overwhelms
her initial theistic belief, then defeat of the design belief will not be
deflected, and indeed S will wind up with a defeater for her initial theistic
belief.[50]
(2) Serious
naturalist
[A
naturalist with a strong belief in naturalism] will have a deflector for
the…design beliefs, and will presumably not form such beliefs… - unless, of
course, the impulse to form those design beliefs is overwhelming; in that case
the impulse to form the design belief will outweigh the potential
belief-deflector.[51]
(3) Neutral
evaluator
For
such a person, encountering a design discourse like Paley’s or Behe’s…will in
all likelihood result in a design belief. But also, for such a person,
encountering the relevant Darwinian considerations I think, will present her
with a partially undermining defeater for those design beliefs.[52]
Q17: Do you agree
with Plantinga’s analyses for the various profiles above? Why or why not?
Plantinga: [W]e
really can’t tell what sort of support, if any, design discourses offer theism
without knowing whether theism is true.[53]
Q18: Assuming
Plantinga is right that we can’t tell by any direct means what sort of support
design discourses offer theism, are there other considerations that might help
us evaluate the significance of apparent design to the debate between theists
and naturalists?
[1] P. 233.
[2] P. 233.
[3] P. 234.
[4] P. 234.
[5] Pliotropy occurs when a single gene influences
multiple traits.
[6] P. 235.
[7] P. 236.
[8] P. 236.
[9] P. 238.
[10] P. 238.
[11] P. 238.
[12] P. 239.
[13] P. 239.
[14] P. 240.
[15] P. 240.
[16] 241-242.
[19] P. 242.
[20] P. 242.
[21] Popular science writer Matt Ridley makes this case in
his book The Red Queen.
[23] P. 242.
[24] P. 243-244.
[25] P. 244.
[26] P. 245.
[27] “I don’t ordinarily form any belief (any explicit
belief, anyway) at all as to how Paul is looking: I move directly to the view
that he is furious.” If we did [form such beliefs on the basis of an inference,
they] would not be well-founded and would certainly not constitute knowledge.”
(p. 249-250, 251)
[28] P. 247-248.
[29] P. 249-251.
[30] P. 251.
[31] P. 251.
[32] P. 251.
[33] P. 252.
[34] P. 255.
[35] P. 255.
[36] P. 255.
[37] P. 256-257.
[38] P. 257-258.
[39] P. 259.
[40] P. 259.
[41] P. 260.
[42] P. 260.
[43] P. 262.
[44] P. 263.
[45] P. 264.
[46] P. 266-267.
[47] P. 268.
[48] P. 268.
[49] P. 268-269.
[50] P. 269.
[51] P. 269-270.
[52] P. 270.
[53] P. 272.
