To illustrate observation, a person sees X and they know X for certain. X can
be many things, for example the sunset this evening, a tree in the local park or
the bowl of fruit on the kitchen table. In each case the person sees something
for themself, and then knows that what they have seen is true. For example,
they know that something is located in a particular place or that an event has
happened. In these cases a person can easily be 100% satisfied as to the truth
of what they saw.
Of course it is always possible that while they ardently believe that something
is 100% true, they are wrong. And it is possible that having seen something
they are not quite sure as to what really happened. So they acknowledge the
fallibility of their observation and say to themselves something like this: “I
thought I saw a rabbit dash out of the bush but I could not be sure”.
Court
Just as humans rely on the evidence of their senses so do courts. A court
receives in evidence an account of what a witness has observed. When the
witness gives their evidence to the court the witness may believe that they have
observed something correctly, that they have remembered it accurately and
told it truthfully, the court is entitled to make up its own mind on these matters.
The point is that there is no guarantee that observational evidence is correct.
When courts scrutinise observational evidence to determine whether or the
extent to which it is true, they resort to two means. One is cognitive science.
This directly scrutinises the evidence. For this the court asks whether the
evidence of the witness is consistent with the capacity of humans to observe
events, to remember them and to recount them in court. The other is induction.
Here the court considers whether the evidence of the witness describing events
squares with the way things usually happen.
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Systematic Observation
Sometimes there is empirical data on the happening of events based on serious
and systematic observation. Examples
are data from surveys of weather,
disease, life expectancy, physiological characteristics (such as blood groups),
rates of divorce and the occurrence of motor vehicle accidents. Literally, these
observations say something like this: “Of all the marriages in the years 1990-
1999, 43% ended in divorce within 10 years”.
This data has been gathered in a scientific method and provides some
evidence for assigning probabilities to the events. The problem is that to use
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Christopher Enright Legal Method
Chapter 23 Probability of Truth: Specific
Facts
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