Certainty and Causation
| Author | Jamie Cassels |
| Profession | Professor of Law University of Victoria |
| Pages | 289-310 |
CHAPTER
10
CERTAINTY
AND
CAUSATION
A.
INTRODUCTION:
PROOF
OF
DAMAGES
The law of
remedies
and the
substantive
law are not
always easily sepa-
rated.
Frequently, problems
in
substantive
law
resurface
when
the
court turns
to the
quantification
of
damages,
and
occasionally
those
problems
may be
solved through remedial innovation. Nowhere
is
this
more true than
in the
relationship between
the
substantive
law of
cau-
sation
and
principles
of
damage assessment. This chapter explains
the
general
principles
of
proof regarding damages assessment, explains
recovery
for
"lost chances,"
and
shows
how an
imaginative approach
to
damages
quantification
can
resolve otherwise intractable problems
of
proof
of
causation.
1)
General
Principles
The
plaintiff
may
recover only damages that
are
caused
by the
defen-
dant's wrong,
and the
onus
of
proof
of
this causal connection
is
upon
the
plaintiff.
The
test
for
proving causation
is the
"but for" test
—
that
the
loss would
not
have occurred
but for the
defendant's breach
of
duty.
The
civil standard
of
proof
is the
balance
of
probabilities
—
that
it
is
"more probable than not" that
the
defendant's breach
of
duty
caused
the
loss.
Typically, proof
of
causation
in
this
sense
is a
matter
of
substantive law. However,
as
will become apparent,
the
burden upon
litigants
facing
such causal uncertainty
has
been lightened somewhat
289
290
REMEDIES:
THE LAW OF
DAMAGES
by
developments
in the law of
remedies, especially through recovery
for
lost chances.
In
addition
to
proving that
the
defendant caused
the
loss,
the
plain-
tiff
must also establish
the
extent
or
quantum
of the
loss. This issue
falls
squarely
within
the law of
remedies.
In all but the
simplest cases there
will
be
some uncertainty about this.
In
contract cases, damages
are
mea-
sured
by the
economic
benefit
to the
plaintiff
had the
contract
not
been
breached.
This requires
the
plaintiff
to
prove
not
only what
he or she
has
directly lost
as a
result
of the
breach,
but
also what benefits might
have
been obtained
had the
defendant
not
breached. This involves
the
construction
of
hypothetical scenarios about what would have hap-
pened
but for the
breach.
The
same
is
true
in
tort cases. Damages
are
assessed
by
determining what would have happened
but for the
tort.
In
both cases
the
plaintiff
bears
the
onus
of
proof.
For
example,
in
the
case
of
claims
for
lost
profit
the
plaintiff
must bring
forward
the
best evidence possible
to
demonstrate what those
profits
might have
been. Such evidence will
be
based
on the
plaintiffs
own
business
records, evidence
from
competitors,
and
expert opinions.
In the
absence
of
evidence
of
some loss,
the
court
may
hold
the
burden
of
proof
against
the
plaintiff
and
award
nothing.1
Even where
the
evi-
dence shows that
a
loss
was
suffered,
the
court will
not
simply specu-
late
about
the
amount
of
that loss,
nor
will
it
simply adopt
the
plaintiffs
best-case scenario without evidentiary
support.2
Vaguely
stated
claims
for
lost
profits
have been denied
in the
absence
of
some
compelling
proof.3
The
rule regarding onus
of
proof,
however, must
be set
against
another general principle: that
the
courts will
not
shirk
the
assessment
of
damages merely because
the
task
is
difficult
or
uncertain. Moreover,
where
the
defendant
has
clearly committed
a
wrong
and has
injured
the
plaintiff,
justice requires that
the
plaintiff
should
not be
denied
compensation
for
harm merely because
the
quantum
of
that harm
is
difficult
to
measure.
In
Canlin
Ltd.
v.
Thiokol
Fibres
Canada
Ltd.,"'
Cory
J.
stated:
The
court,
I
believe, would
be
shirking
its
duty
if it
were
to say
that
no
damages
should
flow
because
of the
difficulty
of
calculating
and
assess-
ing
such damages
and
that they
are
therefore
too
remote.
An
assessment
1
Cotter
v.
General
Petroleums
Ltd.,
154.
2
R.G.
McLean
Ltd.
v.
Canadian
Vickers
Ltd., [1971]
1
O.K.
207
(C.A.).
3
Sunshine
Vacation
Villas
Ltd.
v.
Hudson's
Bay Co.
(1984),
58
B.C.L.R.
33
(C.A.).
4
(1983),
40
O.R.
(2d)
687
(C.A.).
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