An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

328
FALLACIES.
(c) Mai-observation and false analogy are implicitly
generalisations which are erroneous. Fallacies of ex
plicit generalisation are, however, even more common
e.g., to generalise from mere enumeration ?>., to make
an enumeratio simplex into a
"
"
law of nature ; to argue
post hoc ergo propter hoc, mistaking mere succession
for true causation ; to generalise in neglect of
"
extreme
cases," which our generalisation ought to cover ; to
neglect counteracting causes or material conditions.
In order to connect these
"
Inductive
"
Fallacies
with the doctrines of Inference already explained, we
may remind the student that a fallacy of observation
is usually a bad enthymeme in the Aristotelian sense
(ch. VII. 3)
in fig. ii. :
e.g.,
All A look so and so,
This looks so and so ;
Therefore this is A.
The inferential character of observation is shown in
that it so readily admits of being expressed in this
form. And a false analogy is essentially
conclusion in fig.
a universal
iii. (ch. VII. 4) e.g. t if a person
infers that all Catholic countries abound in beggars
from the cases of Italy, Spain, &c., and then applies
the conclusion to France. 1
The student must remember that both good observa
tions and good analogies, when "formally" expressed,
display the faults of affirmative conclusions in fig.
ii.
or universal conclusions in
fig.
iii. But though from
the purely
"
"
formal
point of view they are all equally
faulty, from the point of view of scientific method they
are not so.
1 We refer of course to the Aristotelian analysis of the Syllogism
of Analogy.