90
THE ESSEX NATURALIST.
landing of Julius Caesar upon our shores by experimental
repetition, yet we hold that event as being fully established by
the evidences that are appropriate to the enquiry.
In like manner the past events of prehistory cannot be
directly verified : they cannot be "proved" in the strict sense
of the word ; they must be inferred from the examination of the
more durable effects that they have left behind them.
If we think of the structure of a science under the simile
of a building made of bricks, then the primary bricks of the
prehistoric edifice are to a very substantial degree not facts at
all, but inferences. For example, the physical properties of
flint are facts relating to sciences such as geology, mineralogy,
chemistry or physics, according to the mode of approach. But
a flint implement—a primary brick of prehistory—is not a fact,
but an inference.
In many cases the associated evidences are so conclusive
that no reasonable person can doubt that the inference is correct,
in others it may be more or less doubtful, or the balance may be
heavily on the other side.
When speaking of fact, perhaps one should not quite forget
that from the more exacting standard of the ultimate analysis
of human knowledge every "fact" available to science is,
strictly speaking, only an inference or interpretation of our
sensations. All knowledge is conditional and relative, but there
are big differences of degree. In the present enquiry we are
not called upon to undertake an ultimate analysis of things ;
we are right in taking our natural concepts of the world around
us at their face value, but we are not right in taking the
"primary bricks" for the building of our prehistoric edifice
with a like uncritical assurance.
Why is it, then, that in prehistory there is such a strong
impulse to follow the line of least resistance, and take the
"primary bricks" (supposed flint implements) for granted,
without enquiring too closely into their merits, and thus run
the risk of building a hollow facade without substantial backing?
It is not easy to find a satisfactory explanation for this attitude
of wishful thinking. Doubtless several different causes or
influences contribute to the result. The "primary bricks" of
prehistory may be too readily assumed to be facts, because