In fact, the reasoning is based on induction. Repeated observation of an
apparent cause and effect relationship without exception or qualification is one
basis of induction. This is illustrated by the following diagram:
Premise
In all observed instances X has property Y.
Conclusion
In all instances X has property Y.
Figure 6.5 Induction for Establishing a Causal Law
Induction that makes a case for a causal law starts with observations. Bit by
bit the truth of a theory or causal law is inferred from observations that are
consistent with it. While the accumulation of evidence will increasingly lend
support to the existence of a causal law, it cannot conclusively prove it
because there is always the possibility of a disconfirming instance. But even
though the reasoning is not watertight it gains more and more strength as more
and more confirming instances are discovered by persistent observation.
Proving Facts
Induction is used to prove facts in litigation. Induction is based on recurring
patterns of behaviour. These patterns may apply to an individual or they may
apply to behaviour generally.
To illustrate how induction can prove facts, assume that there is a common
pattern of behaviour in which Facts A, B and C occur together and in
sequence. Assume now that a court has found that Fact A and Fact C have
happened. In this case there is an argument based on induction that Fact B has
also occurred.
There is a famous literary example of inductive reasoning in one of Sir Arthur
Conan Doyle’s short stories about his detective Sherlock Holmes. The story is
entitled Silver Blaze. Silver Blaze was
the name of a champion racehorse. It
was kept at the King's Pyland stables in the country in Dartmoor, which were
near the large house of the horse’s owner, Colonel Ross. On the night before
an important race Silver Blaze mysteriously disappears. At the same time, the
horse’s trainer, John Straker, is found dead, apparently murdered. After
Sherlock Holmes conducts his investigation he has the following exchange
with a Scotland Yard detective Inspector Gregory:
Gregory: "Is there any other point to which you would wish to draw my
attention?"
Holmes: "To the curious incident of the dog in the night-time”.
Gregory: "The dog did nothing in the night-time”.
Holmes: "That was the curious incident”.
Holmes was reasoning inductively. Commonly a dog will bark at a stranger,
especially in the nighttime. However, when a dog does not bark in the presence
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