WAYS OF NATURE 
things that one man alone had reported having 
seen, — things so at variance not only with my own 
observations, but with those of all other observers 
and with the fundamental principles of animal psy- 
chology, that my “ will to believe,” always easy to 
move, balked and refused to take a step. 
In matters of belief in any field, it is certain that 
the scientific method, the method of proof, is not of 
equal favor with all minds. Some persons believe 
what they can or must, others what they would. One 
person accepts what agrees with his reason and 
experience, another what is agreeable to his or 
her fancy. The grounds of probability count much 
with me; the tone and quality of the witness count 
for much. Does he ring true? Is his eye single? 
Does he see out of the back of his head ? — that is, 
does he see on more than one side of a thing? Is 
he in love with the truth, or with the strange, the 
bizarre? Last of all, my own experience comes in 
to correct or to modify the observations of others. 
If what you report is antecedently improbable, I 
shall want concrete proof before accepting it, and 
I shall cross-question your witness sharply. If you 
tell me you have seen apples and acorns, or pears 
and plums, growing upon the same tree, I shall dis- 
credit you. The thing has never been known and 
is contrary to nature. But if you tell me you have 
seen a peach tree bearing nectarines, or have known 
a nectarine-stone to produce a peach tree, I shall 
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