Order from chaos? Maybe not, but at least I'm trying...
This is a revised version.
SCIENCE AND
JUDGEMENT BY EYE
IN THE HISTORICAL
IDENTIFICATION
OF WORKS OF ART
by
MARTIN KEMP
Introductory
remarks
This
essay reworks the more theoretical sections of the paper delivered at the
Authentication in Art congress at the Louwman Museum in the The Hague on 7th
May 2014[1] It
does not include the two case studies drawn from Leonardo da Vinci: the
controversy over the two prime versions of the Madonna of the Yarnwinder; and the attribution of the Salvator Mundi, which made its public
debut in Leonardo da Vinci. Painter at
the Court of Milan at the National Gallery in London in 2011.[2] The
paper was an attempt to bring some ordered thinking into how we judge the
status of the varied kinds of evidence that can now be brought to bear upon the
attribution of old master paintings. It focused particularly on the often
conflicting claims of connoisseurship and scientific analysis. I did not
attempt to offer a historical review of the criteria used for attribution,
which was the subject of other papers in the conference. Nor am I here
anticipating potential new techniques, such as analysis by computer vision.
I am
advocating that we replace the term “connoisseurship” with “judgment by eye”,
unless we are dealing with attribution within a specific historical context. I
do so for two reasons. The first is that “connoisseurship” has increasingly
come to carry negative associations - identified with a self-proclaimed (and
often class-based) elite whose skills are insulated from systematic scrutiny. The
second and more important is that “judgment by eye” signifies skills that
extend to any arena in which subtle judgments need to be made about complex and
often slippery visual evidence. Looking at computer-generated images of a
distant galaxy or X-rays of a breast tumour involve judgment by eye to no lesser
degree than scrutinizing visual evidence about a work of art. In the case of
the scientific examination of paintings by such techniques as X-radiography or
infrared reflectography judgement by eye in art and science intersect in an
intimate manner. Judgement by eye embraces all those factors, physiological,
psychological, cogntive and personal that are involved in and direct our acts
of seeing.
What we
conceive to be the most relevant and powerful methods of judgment by eye rely
upon a series of tacit assumptions about what is significant in the making and viewing of a particular
work of art. I will begin with a brief philosophical excursus on causal explanations,
visual evidence and the standpoint of the observer. This will be followed by
some thoughts on falsifiability.
An excursus on
causes and the stance of the observer
The
example that I used some years ago is a car crash.[3] A car
has skidded off a road at a bend and damaged itself (but not the driver) by
striking a tree. A series of experts seek an explanation. The most important,
at least financially, is the representative of the insurance company, who is
interested in finding reasons not to pay out. He or she notices that a tread on
one of the tyres is below the legal limit. This is therefore the “cause” of the
crash, and the driver’s insurance claim is invalidated. A local authority road
engineer notes that the camber of the road at the bend is sloping in the wrong
direction and that the tree could not be is a worse position for anyone coming
of the road at that bend. A meteorologist explains that there was a very light
shower a few minutes earlier and that there had been no rain for the previous fortnight,
making the road skiddy. A psychiatrist characterises the driver as a risk-taker
who tends to drive dangerously fast. The driver claims that a cat ran out in
front of him, causing him to swerve. And so on. There are also a series of more
general causes, such as the fact that wheels are round and can roll fast, and
that petrol and air combine to make an explosive mixture.
None of
these causal explanations is demonstrably wrong and it is likely that one of
them alone is not sufficient. It is possible that all of them were necessary for the accident to happen. Each of the observers will select and
prioritise different kinds of evidence depending on their standpoint.
If we
take this notion of the standpoint of the observer into works of art, we can
see that a comparable variability of seeing applies. Someone concerned with the
sociology of art will be interested in such aspects as the economic transaction
that brought it about and the social “message” of the work – overt or covert. A
feminist may concentrate on the way that gender is handled in a painting, as
when a female nude is presented for a male voyeur’s gaze. The iconographer
undertakes a close analysis of its symbolic and allegorical content in the
context of relevant texts. The style historian (if such a thing still exists) characterises
it within broad procession of stylistic developments. The monograph writer sees
each work as a manifestation of the artist’s individual production and creative
personality. The connoisseur delights in
the aesthetic qualities of the painting. The owner (or even the museum curator)
takes a pride in possession that grants a special aura to the picture in her or
his eyes. The auctioneer or dealer will seize upon those characteristics that will
be most efficacious in the act of selling. The conservator will focus on the
condition, looking closely as nasty re-paints. Someone who discovers a painting
and is the first to publish it will search out those things that best support
the attribution. The press will look for whatever creates a “story”. And so on.
This is not to say that each observer is necessarily blind to the visual
qualities that the others highlight, or that one way of looking is more right
than another, but it is true to say that each will see in a way coloured by
their interests and observational skills.
The
central message of these simplified examples is that seeing is a very selective
and malleable business. It is not arbitrary – everyone saw the crushed front of
the car and knew that an accident had occurred - but what is seen within a framework of explanation
is powerfully shaped by what the observer wants to see and what we are looking
for, given our set of interests.
A
personal anecdote will serve to illustrate this point. I recall in a biology
class at school that we were dissecting rats. We had previously tackled mice
and other animals. The master, Dennis Clark, who was an outstanding teacher,
asked us to find the rat’s gall bladder. When, after a decent interval, he
enquired about our success, I was one of the first to put up my hand. I rather
fancied myself as a dissector. “It’s a funny thing”, he said, “rats do not have
gall bladders”. It was relatively easy for him to falsify our observations by
showing that we had contrived to translate some feature within the rat’s
abdomen into the desired gall bladder.
The status of
observation and explanation in terms of refutability
Potential
falsifiability is a key aspect of any process of observation and explanation.
In this I am drawing upon Karl Popper, the philosopher and theorist of
scientific methods - without necessarily endorsing all aspects of his stance on
science. Popper laid down a series of
propositions, including:
It is easy to obtain confirmations, or verifications, for nearly every
theory - if we look for confirmations….
A theory which is not refutable by
any conceivable event is nonscientific. Irrefutability
is not a virtue of a theory (as people often think) but a vice.
Every genuine test of a theory is an
attempt to falsify it, or to refute it. Testability is falsifiability; but
there are degrees of testability: some theories are more testable, more exposed
to refutation, than others…
Confirming evidence should not count
except when it is the result of a genuine test of the theory…
Some genuinely
testable theories, when found to be false, are still upheld by their admirers —
for example by introducing ad hoc some auxiliary assumption, or by
reinterpreting the theory ad hoc in such a way that it escapes
refutation. Such a procedure … rescues the theory from refutation only at the
price of destroying, or at least lowering, its scientific status. [4]
Amongst
the procedures that can be applied in attribution, some are subject to falsification
on their own terms and may serve
definitively to falsify an attribution, such as pigment analysis. Others are
definitely not falsifiable on their own
terms, most notably traditional connoisseurship. This means that any
attempt to place connoisseurship on a scientific basis must necessarily
fail. This is not to say we should only
be permitted to utilise arguments that can be subjected to hard falsification,
but it does affect the status of non-falsifiable techniques in any process of
argumentation.
To Popper’s
falsification I would add my version of Ockham’s razor. This is the lex
parsimoniae, which states that the hypothesis with fewest assumptions and
is most consistent with the evidence - i.e. the most parsimonious – is to be
preferred. When
too many qualifying (and untestable) theories need to be aggregated to save a
hypothesis, the hypothesis itself should be questioned, as with Copernicus’s
questioning of the mechanisms invented to save the Ptolemaic system. The most
parsimonious explanation might not be right, but it is the only systematic way
to proceed. Too often art historians aggregate a elaborate and arbitrary
mish-mash of secondary arguments that look clever and serve the needs of their preferred
attribution but have no secure status in any systematic process of argumentation,
since they escape refutation in themselves and, if inverted, cannot falsify the
attribution.
Constructive and Permissive Arguments
The kinds
of evidence and explanation that can he subject to various degrees of
falsification can be grouped under two headings: constructive and permissive.
By constructive I mean those that add positively and accumulatively to the case
being made for a specific attribution. By permissive I am signalling those that
present no obstacle to the attribution being made, i.e. they offer a nil obstat. These two types of argument
are regularly confused and even conflated in processes of attribution.
I will
use three tables to give a sense of the hierarchies involved, looking first at characteristics
of a painting that are subject to scientific analysis. I am not trying to
present a comprehensive list of scientific techniques in any of the tables. Rather
I am giving examples that will allow others to be considered in terms of their
place in the hierarchies. By “strong falsification” I mean that the scientific
evidence is transparent and fully testable. It also offers strong falsification
for attribitions. In general we can see that the scientific evidence is genenrally
weak for constructive arguments and strong for the permissive ones.
There is
inevitably some schematisation involved in drawing up the the table, not least
because scientific techniques, including pigment analysis, cannot wholly
exclude some degree of judgement by eye. We are not dealing with certainties when
technology is applied to the scientifc analysis of works of art. By “scientific
analysis” I refer to those techniques of examination that deploy science via
technologies to define the physical and/or chemical nature of the artefacts.
|
CONSTRUCTIVE
Contributes
additively to
the
accumulation of
positive
evidence
(Strong
falsification for
ones in blue
but weak for
constructive
arguments )
|
PERMISSIVE
Nil obstat – contributes
subtractively
to remove
obstacles.
(Strong
falsification
for all in
blue)
|
|
|
Condition
helps to understand
present appearance
|
Condition
helps to understand
present appearance
|
|
|
Support
generally not specific to the artist
|
Support
OK for the artist, period place…
|
|
|
Pigments
rarely specific to the artist
|
Pigments
OK …
|
|
|
Binders
rarely specific to the artist
|
Binders
OK …
|
|
|
Layers
occasionally specific to the artist
|
Layers
OK …
|
|
|
Priming
occasionally specific to the artist
|
Priming
OK …
|
|
|
Process of
execution
pentimenti, underdrawing,
underpainting etc.
of a kind specific to the artist – but requiring a lot of judgement by eye
|
Preparatory
procedures
Consistent with
expectation
|
|
The next table is devoted to aspects of
scientific analysis in order of specificity to the act of attribution to a
named artist. Those that are most specific involve the highest degrees of
judgement by eye when interpreting the images. They are ordered according their
degree of malleability, with the most malleable at the top.
In this and the following table, I am using
the terms “scientific” and “art historical” in a conventional way without
intending to signal that they can be isolated in the actual pratice of
attribution – and certainly not to suggest that the application of scientific
analysis necessarily delivers more certainty than art historical evidence. In
the actual practice of art history, its isolation from scientific analysis is
all too common.
|
“SCIENTIFIC”
(indicative not comprehensive)
|
|
Multi-spectral and other scanning methods to
disclose images in lower layers (large volumes of complex visual
information but difficult to read and needing much judgement by eye)
|
|
X-rays (difficulty of reading. Many layers at
once. Much judgement by eye)
|
|
I-R, especially reflectograms (not always
easy to read but good for underdrawings. Moderate or high level of judgement by eye)
|
|
U-V (informative
about re-touchings but limited applicability. Moderate level of judgement by
eye)
|
|
False colour
analysis (Moderate level of judgement by eye)
|
|
Analysis of
binder(s). (Moderate to high level of judgement by eye)
|
|
Optical analysis of
layers by cross-section samples
(Moderate to high
level of judgment by eye)
|
|
Carbon dating
(crude for specific attributions and only offering a nil obstat)
|
|
Pigment analysis of various kinds (generally offers only a nil obstat)
|
The third table deals with the criteria
that are more traditionally “art historical”. Again the most malleable are at
the top. Here I have added standard kinds of evidence relating to provenance
and documentation that are highly constructive. The terms “outside” and
“orbital”. warrant some explanation.
“Outside” refers to evidence from other fields of expertise that are
relevant to the attribution, such as costume. “Orbital” refers to the
contextual factors in the period and more specifically within the artist’s
career. For example, in looking at the
newly discovered Salvator Mundi we
can show there are elements in the optical characterisation of the hand and
head that correspond to Leonardo’s analyses of the eye and light. The
transformation of the customary orb into a rock crystal sphere of the heavens corresponds
to Leonardo’s documented interests. Any new attribution will ideally play an active role in our characterisation of
the orbital factors that shape our understanding of the work in its contexts.
|
“ART HISTORICAL”
|
|
overall judgment by eye (general impression)
|
|
detailed judgements by eye (e.g. brushwork)
|
|
wide current consensus of judgment by eye
|
|
chronological persistence of
consensual judgment by eye
|
|
supporting evidence from content
|
|
supporting evidence from “outside”,
e.g. costume
|
|
integration
into and leverage on the “orbital
factors” of
the historical context, including the artist’s life and works.
|
|
primary documentation
|
|
provenance
|
|
provenance and documentation
wholly integrated
|
Judgement by
eye
As we
have stressed, judgement by eye plays a key role in key scientific techniques. Although the most constructive of the kinds
of art historical evidence, documentation and provenance, do not rely upon
judgement by eye, it is common that this kind of evidence is not available or
is less conclusive than we would wish. In many cases judgement by eye
necessarily provides the actual starting point, before other kinds of
investigation are undertaken. This is often the situation when a previously
unknown or unrecognised work first emerges with specific claims attached to it.
Let us
try to formulate some propositions about judgement by eye in a somewhat Popperian
manner.
Attribution that is reliant on judgement by
eye may be described as an intuitive hypotheses that has substantial
implications and consequences.
The implications and consequences range from
the financial value of the item to its effect on the context of orbital factors
into which it is being inserted. A significant implication is that the work
will actually look different once an
attribution has been mooted (whether or not it is accepted), since the visual
object is now located in a context of overt and specific comparisons. The
attribution will affect our view of the artist to a greater or lesser degree. The
attribution may well affect the attributor in personal and professional terms. The
reputation of the attributor affects how the attribution is regarded, as does
the operation of petty professional jealousies and rivalries. The current
ownership of the work and how it emerges into the public domain tends to affect
how it is viewed. The owner (private or public) will certainly be affected. The
implications will feed back into how
we view the attribution. There is a great deal of “noise” in this two-way
process of implications and consequences.
At its best and most disinterested, judgement
by eye aspires to non-arbitrary subjectivity.
By this I
mean that the subjective judgement can be set within a framework of rational
argument, accumulated knowledge and relevant experience, not least with respect
to visual comparisons. But in itself a hypothesis of attribution that relies
wholly or primarily on judgement by eye must necessarily remain provisional,
given the malleability of acts of seeing and the lack of any internal process
of falsification.
The hypothesis of attribution is given
non-arbitrary support to varying degrees by orbital associations and outside
evidence.
The hypothesis of attribution may be
supported permissively by scientific evidence. It may in some cases be
supported constructively by scientific evidence.
The hypothesis of attribution may be
supported constructively by primary documentation and provenance. When primary documentation and
unbroken provenance coincide, confirmation is strong (though never 100%
watertight, particularly for those who wish to dissent).
The
hypothesis of attribution is subject to strong falsification by primary
documentation and provenance.
The
hypothesis of attribution is subject to strong falsification by scientific
evidence (which is itself falsifiable).
Conclusion
Attribution
is by its nature a hybrid process that utilises arguments that are
incommensurable in method.
Judgment
by eye is malleable in the light of multiple interests.
Judgement
by eye is falsifiable only by factors outside itself.
The visual techniques, “art historical” and “scientific”, that are most specific in
the process of identification are those that are the most malleable.
We should strive to recognise the effective
status of different kinds of evidence
and argument, not over-claiming and/or granting a monopoly to any one type of
argument unless it offers hard falsification. We should recognise whether
evidence is constructive or permissive. We should remain perpetually alert to
the malleability of our seeing, and to the varied personal and contextual
factors that operate selectively in what we claim to see. Above all we should be more modest and
prudent in our personal investments in our acts of seeing.
[1] Thanks are due to Milko den Leeuw and Nicholas
Eastaugh, the guiding lights of the initiative that lead to the congress, and
Evert Louwman who hosted the event in his magnificent museum. Some of the
material had been presented at the European Union conservation conference under
the umbrella of the CHARISMA project in Florence on 6th March 2014,
and in a public lecture at the Department of Art and Archeology in Princeton on
15 April 2103. I am grateful to Nicholas Eastaugh and Jilleen Nadonly for their
constructive comments on this paper.
[2] For the Madonna of the Yarnwinder see M. Kemp, “From Scientific Analysis to
the Renaissance Market: the Case of Leonardo's Madonna of the Yarnwinder”, The Journal of Medieval and Renaissance
Studies, XXIV, 1994, pp.259-74; and M. Kemp and T. Wells, Leonardo da Vinci’s Madonna of the Yarnwinder. A Historical and
Scientific Detective Story, London, 2011. For the Salvator Mundi, see Luke
Syson in Leonardo da Vinci. Painter at
the Court of Milan, London, National Gallery, 2011, pp. **; and a forthcoming book by M. Kemp and M. Dalivalle.
A complimentary approach via abductive reasoning is provided by Douglas Walton,
“An Argumentation Model of Forensic Evidence in Fine Art Attribution”, AI & Society, 28, 2013, pp. 509-30.
Walton uses the example of the La Bella
Principessa, attributed to Leonardo. See most recently, M. Kemp, Leonardo da Vinci. Ritratto di Bianca Sforza,
“La Bella Principessa”, exhibition catalogue, Palazzo Ducale, Urbino, 2014.
[3] M. Kemp, “The Taking
and Use of Evidence, with a Botticellian Case Study”, The Art Journal, XLIV, 1984, pp. 207-15. The argument is adapted
from the philosopher Bas van Fraassen.
[4] Karl Popper, Conjectures and Refutations. The
Growth of Scientific Knowledge, London, 1963, pp. 343-4.
No comments:
Post a Comment