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Geotechnical News • December 2012
15
CANADIAN GEOTECHNICAL SOCIETY NEWS
2012 Legget Medal Award acceptance speech:
Dr. E.C. McRoberts
I am honored to have been selected by
the Canadian Geotechnical Society to
receive their most prestigious reward,
the R.F. Legget Medal. This measure
of professional recognition by one’s
colleagues is indeed a great and heart-
felt pleasure. My thanks are also due
to the awards committee, and to those
who nominated and supported my
award. My colleagues past and present
in one way or the other have contrib-
uted to my being here today. And most
important of all, I must acknowledge
the many clients who have entrusted
me with responsible charge on their
projects.
It is customary at the Legget award
to also pass on some thoughts. Let us
follow up on the issue of “judgment”
most appropriately put forward by
Legget (1979) who in the 13th Terza-
ghi Lecture expressed the view:
“No computer is ever going
to decide when a suitable
foundation bed is reached,
or when tunnel supports are
necessary. In the final analysis
it is human judgment that makes
possible the safe uses of the
earth. And judgment is based on
sound experience that, whether
recognized or not, includes an
instinctive appreciation of all
geological factors”.
This is echoed by Peck (1980) in the
5th Bjerrum Memorial Lecture who
asks “Where has all the judgment
gone?” and comments:
“as long as the myth persists
that only what can be calculated
constitutes engineering, engineers
will lack incentive or opportunity
to apply the best judgment to the
crucial problems that cannot be
solved by calculation”
Both Legget and Peck were warning
against too much emphasis on analy-
sis. Today these cautions are as sound
as they were more than three decades
ago. Even more so, given the increas-
ing and often illusory sophistication of
models. So what is judgment? In his
paper Peck tended to define judgment
by what it is not. And to paraphrase
Vick (2002), judgment is not the
last refuge of the analytically inept,
nor some geotechnical metaphysics
necessarily only possessed by senior
citizens. Vick has an interesting quote
apparently attributable to Mark Twain:
“Good judgment comes
from experience. And where
does experience come from?
Experience comes from bad
judgment.”
This sounds just about right, and the
ability to learn from mistakes is vital,
but even better to learn from the mis-
takes of others so as to limit your own.
For this, reading of case records is so
important but it is a challenge for our
profession to get these lessons pub-
lished in the face of legal constraints
and secrecy limitations that constrain
discourse.
Vick (2002) refers to judgment as
“good thinking”. More recently Marr
(2006) emphasizes that judgment
equates to “critical thinking”. Marr
observes:
It is fascinating that the definition
of critical thinking by prestigious
intellects of our time equates
critical thinking to judgment. Is
critical thinking the same as that
elusive term we all draw upon and
call “engineering judgment”? Is
critical thinking what Peck was
questioning in his 1980 paper on
where has the judgment gone?
So today we arrive at a clear answer;
judgment is “critical thinking”. Marr
cites education studies that define the
elements of critical thinking as: inter-
pretation, analysis, evaluation, infer-
ence, explanation, and self regulation.
On first reading, I found many of the
points made by Marr lining up well
with all my hard earned perspectives,
and learned more besides. Marr also
takes an appropriately less nihilistic