THE ENTOMOLOGIST’S 
WEEKLY INTELLIGENCER. 
No. 10.] SATURDAY, JUNE 7, 1856. [Price 1 d. 
ERRORS OF OBSERVATION. 
(From a Correspondent ). 
At a time when Entomology seems 
taking such a stride as at present, and 
when the ‘ Intelligencer’ is bringing such 
a number of new observers into the field, 
a few remarks on the nature of observa- 
tion, and the liabilities to error incident 
to it, may not be inappropriate. 
When a person makes an observation, 
which subsequently proves to be incor- 
rect, he lays the blame on his senses, 
and says they deceive him: this, how- 
ever, is not the case, for from the point 
of view from which we are now looking 
at the subject our senses never do de- 
ceive us: the error lies in confounding 
an inference drawn by the mind with a 
fact observed by the senses. In the well- 
known trick of a man whistling like a 
flute, a person, on finding that the flute 
was played by an unseen performer, ex- 
claims “ How my senses deceived me;” 
whereas, in fact, he deceived himself: 
his eye told him that the performer’s 
mouth moved in a certain manner; his 
ear told him of certain sounds corres- 
ponding to these movements ; but the 
putting these two observations together 
and drawing from them the inference 
that the sound came from the mouth of 
the performer, was an action of the mind, 
and entirely independent of the senses. 
The amount of error caused in this way 
is incalculable, and would not be be- 
lieved by any one whose attention had 
not been drawn to the subject. Where 
the inference is correct it may pass mus- 
ter as an observation without doing much 
harm to any one, except the observer, on 
whose mind it must have a bad effect, 
but if it is incorrect it must do harm, 
not only by the amount of error diffused, 
but by the doubt cast upon other and 
better observations and well-drawn in- 
ferences. 
To mention a few instances bearing 
on the science of Entomology: an insect 
is caught on the wing in good condition 
at two different times in the year; there- 
fore it is double-brooded! Two insects, 
which are much alike, and yet have 
some constant distinction, are taken, the 
one always in the spring, the other 
always in the autumn ; therefore they 
are two species ! An insect is taken, the 
male in abundance, the female but 
rarely ; therefore the male is more abun- 
dant than the female! or perhaps an in- 
sect is taken which agrees with the de- 
scription of some rarity ; therefore the 
rarity has been taken ! In each case the 
inference may be right, or it may be 
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