generally involve “a global assessment of a whole complex array of
matters”.
230
This has led, not surprisingly, to the view that it is misleading to
try to give these probabilities “numerical expression”.
231
In most cases putting a numerical measure on probability is an estimate at best
and probably no more than a guess.
232
Nevertheless, there are three advantages
at least in conceiving probability in numerical terms rather than using mere
verbal formulas.
First, it makes the position much clearer. A probability of 75% is more telling
than being “fairly certain”. Referring to numerical probabilities is a simple way
of explaining the uncertainty of fact finding and the reasoning that underlies the
task.
Second, it makes for easier comparison. We can see the large gap between a
probability of 95% and 5%, and how little difference there is between a
probability of 50% and a probability of 51%.
Third, and this is the major reason, many of the processes in finding facts
involve using specific probabilities to calculate a further probability and using
this further probability to continue the process. Obviously if probability is not
expressed in numbers it is not possible to do these calculations. Of course it
would be possible to apply the logic of the calculations to verbal expressions
of probability, but this would be clumsy, especially compared to the
calculations that perform the process so easily.
Step 3. Standard of Truth
When Step 2 has been completed, the court has estimated, either in figures or
words, the probability that each version of the fact it true. In Step 3 the party
compares this estimated probability with the probability required by the
standard of proof. When this is done the outcome is simply stated. If the party
who must meet the standard does so they win the case. If this party does not
meet the standard the other party wins.
Function of Probability
It is common occurrence that we humans are uncertain about something such
as the happening of some event in the future. In these cases probability can be
___________________
230
Hodgson (1995) p 738
231
Hodgson (1995) p 738
232
To reinforce the point, in Briginshaw v Briginshaw (1938) 60 CLR 336 at 361-
362 the High Court said that there can be “indefinite gradations of certainty” that
the facts portrayed by evidence are true.
 |
 |
 |