n quiescence.
Nevertheless, we feel no temptation to say that the animal desired what
occurred, partly because of the obviously mechanical nature of the whole
occurrence, partly because, when an animal survives a fall, it tends not
to repeat the experience.

There may be other reasons also, but of them I do not wish to speak yet.
Besides mechanical movements, there are interrupted movements, as when
a bird, on its way to eat your best peas, is frightened away by the boy
whom you are employing for that purpose. If interruptions are frequent
and completion of cycles rare, the characteristics by which cycles
are observed may become so blurred as to be almost unrecognizable. The
result of these various considerations is that the differences
between animals and dead matter, when we confine ourselves to external
unscientific observation of integral behaviour, are a matter of degree
and not very precise. It is for this reason that it has always been
possible for fanciful people to maintain that even stocks and stones
have some vague kind of soul. The evidence that animals have souls is
so very shaky that, if it is assumed to be conclusive, one might just as
well go a step further and extend the argument by analogy to all matter.
Nevertheless, in spite of vagueness and doubtful cases, the existence
of cycles in the behaviour of animals is a broad characteristic by which
they are prima facie distinguished from ordinary matter; and I think it
is this characteristic which leads us to attribute desires to animals,
since it makes their behaviour resemble what we do when (as we say) we
are acting from desire.

I shall adopt the following definitions for describing the behaviour of
animals:

A "behaviour-cycle" is a series of voluntary or reflex movements of an
animal, tending to cause a certain result, and continuing until that
result is caused, unless they are interrupted by death, accident,
or some new behaviour-cycle. (Here "accident" may be defined as the
intervention of purely physical laws causing mechanical movements.)

The "purpose" of a behaviour-cycle is the result which brings it to an
end, normally by a condition of temporary quiescence-provided there is
no interruption.

An animal is said to "desire" the purpose of a behaviour cycle while the
behaviour-cycle is in progress.

I believe these definitions to be adequate also to human purposes and
desires, but for the present I am only occupied with animals and with