18 CHAPTER 1 The Environmental Challenges We Face
papers on which such media reports are based, however, you
would find that all the scientists involved probably made very
tentative conclusions based on their data. Science progresses
from uncertainty to less uncertainty, not from certainty to
greater certainty. Thus, science is self-correcting over time,
despite the fact that it never “proves” anything.The Importance of Prediction Scientists formulate
hypotheses (plural of hypothesis) based on what they
think to be true based on prior scientific work. A hypoth-
esis is a statement of that expectation. A hypothesis is use-
ful if it can be falsified (shown to be wrong) and tested.
A hypothesis is a prediction that can be subjected to ex-
perimentation. When an experiment refutes a prediction,
scientists must carefully recheck the entire experiment.
If the prediction is still refuted, then the hy-
pothesis must be rejected. The more verifiable
predictions a hypothesis makes, the more valid
that hypothesis is.
Each of the many factors that influence a
process is called a variable. To evaluate alterna-
tive hypotheses about a specific variable, it is
necessary to hold all other variables constant so
that they are not misleading or confusing. To test a hy-
pothesis about a variable, we carry out two forms of the
experiment in parallel. In the experimental group, the
chosen variable is altered in a known way. In the control
group, that variable isn’t altered. In all other respects, the
experimental group and the control group are the same.
We then ask, “What is the difference, if any, between the
outcomes for the two groups?” Any difference must be due
to the influence of the variable we changed because all
other variables remained the same. Much of the challenge
of science lies in designing control groups and in success-
fully isolating a single variable from all other variables.Theories A theory is an integrated explanation of numer-
ous hypotheses, each of which is supported by a large body of
observations and experiments. A theory condenses and sim-
plifies many data that previously appeared to be unrelated.
Because a theory demonstrates the relationships among dif-
ferent data, it simplifies and clarifies our understanding of
the natural world. A good theory grows as additional infor-
mation becomes known. It predicts new data and suggests
new relationships among a range of natural phenomena.
Theories are the solid ground of science, the expla-
nations of which we are most sure. This definition con-
trasts sharply with the general public’s use of the word
theory, which implies lack of knowledge or a guess. In thisdata. Thus, scientists never claim to know the final answer
about anything because scientific understanding changes.
This is not to say, however, that all ideas are equally
valid. Rather, the scientific processes evaluate and then
reject ideas that are inconsistent with theory and data.
Thus, despite many uncertainties, science provides us-
able insights on many aspects of environmental change
and management. While science tells us what is and what
can be, it cannot tell us what should be. Questions about
what should be are in the realm of religion, ethics, policy,
and philosophy. Once we have used these approaches to
decide on our priorities and preferences, science is the
most useful tool available to help us achieve them. Sci-
ence aims to discover and better understand the general
principles that govern the operation of the natural world.
The Scientific Method The established
processes that scientists use to answer ques-
tions or solve problems are collectively called
the scientific method. Although there are
many variations of the scientific method, it ba-
sically involves five steps:
- Recognize a question or an unexplained phenome-
non in the natural world. - Develop a hypothesis, or the expected answer to the
question. - Design and perform an experiment to test the
hypothesis. - Analyze and interpret the data to reach a conclusion.
- Share new knowledge with the scientific community.
Although the scientific method is often portrayed as a
linear sequence of events, science is rarely as straightfor-
ward or tidy as the scientific method implies (Figure 1.10).
Good science involves creativity, not only in recognizing
questions and developing hypotheses but also in designing
experiments. Because scientists try to expand our current
knowledge, their work is in the realm of the unknown.
Many creative ideas end up as dead ends, and there are
often temporary setbacks or reversals of direction as scien-
tific knowledge progresses. Scientific knowledge often ex-
pands haphazardly, with the “big picture” emerging slowly
from confusing and sometimes contradictory details.
Scientific discoveries are often incorrectly portrayed in
the media as “new facts” that have just come to light. At a later
time, additional “new facts” that question the validity of the
original study are reported. If you were to read the scientific
scientific method
The way a scientist
approaches a prob-
lem, by formulating a
hypothesis and then
testing it.