Page 92 - Modern Spatiotemporal Geostatistics

Physical Knowledge 73

interdisciplinary research focusing on two crucial areas: (i.) unifying scientific
disciplines, and (ii.) linking contamination with health endpoints for disease
prevention and intervention. These endpoints include, e.g., infectious diseases,
cancer, birth defects, immune system dysfunction, behavioral abnormalities,
decreased fertility, and altered metabolism.

An important characteristic shared by both the Q and S knowledge
bases is that they should be reliable, meaning that the geostatistician can
depend upon them in terms of predictability. Indeed, the geostatistician's per-
sisting goal is to understand phenomena to such an extent that the qual-
ity of space/time mapping can be consistently improved. It is only through
valid, organized physical knowledge bases that truly scientific mapping can be
achieved. The two knowledge bases are described in considerable detail in the
following sections.

The General Knowledge Base

The general knowledge base Q relies on our ability to draw on the experience
of previous generations and the discoveries of others in the present. Therefore,
Q denotes the background knowledge and the justified beliefs relative to the
mapping situation overall, and it may include laws of science and universal
statements that make claims about the properties of some aspect of the uni-
verse, structured patterns and assumptions, local (phenomenological) theories,
previous experience with similar situations independent of any case-specific ob-
servations, analytic statements (justified on the basis of relations of concepts
and theories), synthetic statements (whose truth or falsehood is a matter of
experience), etc. The knowledge offered by these statements is considered
"general" in the sense that it is vague enough to characterize a large class of
fields or situations.
EXAMPLE 3.2: The statements "acids turn litmus red," "the ozone concentra-
tion field has specified mean and covariance," and "subsurface flow is governed
by Darcy's law" are general statements. Indeed, all acids have the property of
turning litmus red, several ozone fields may share the same mean and Co-
variance, and various flow fields satisfy Darcy's law. Such statements thus
constitute general knowledge.
From an epistemic viewpoint, the general knowledge base Q may be di-
vided into two main categories:
• Analytic knowledge, which involves abstract quantities, symbols, logical re-
lations, concepts, etc. without real counterparts (e.g., "if A or B and not
B, then A"). Other analytical statements may have real counterparts, but
their validity is a matter of definition and/or logic only (e.g., "soil permeability
values are nonnegative," or "all sisters are female").
• Synthetic knowledge, which involves statements of fact, laws, and theories.
The law of gravitation, e.g., states that "two bodies exert a force between each