knowledge, science, and the universe chapter 1 - Physical Science ...

SECTION 1–3 Six “Self-Evident Truths” 7
physical systems. You will read about many
models in this book. Models are often pictorial
and may emphasize some concepts while
neglecting others. They may sometimes be
expressed in terms of mathematics. The predictions
of models are tested against the outcome
of experiments—using sensory data—and models
that don’t work are revised or rejected. If
successful models cannot be built upon the theories,
then the theories themselves are called
into question. Models that work are kept and
tested again. As they pass more tests, trust in
their accuracy and truthfulness increases. The
cycle is repeated with the trust that the process
is progressing toward an enlarged, better understanding
of nature’s truth.
Scientific research is always a test of a
hypothesis, theory, law, or model against the
behavior of nature. This is the critical feature,
the hallmark of science— consistency with nature.
Any idea that is not or cannot be tested against
nature cannot properly be included in scientific
knowledge. Some “pseudoscientific” theories
claim to be science but fail this test. Ideas rise
and fall by this condition, and are always tentative
to some degree because there is always
some possibility, however small, of disagreement
with future experiment.
The scientific method is a priceless tool,
which, when powered by curiosity, helps us efficiently
comprehend our complex world. It
helps our curious minds formulate important
“why” and “how” questions. It helps us sift
through clouds of variables and possible answers
to find the few laws and principles through
which a broad range of phenomena can be
understood.
1–3 SIx “SELf-EVIdENT
TRuThS”
All reasoning rests upon assumptions. In
science we use a set of assumptions or rules to
evaluate our knowledge. These rules are so logical
and basic that we present them here as six
“self- evident truths.”
1. Existence: There exists a physical world separate
and distinct from our minds that is
comprehensible through our senses. This
world is governed by certain generalities
called the “laws of nature.”
figure 1.6
Existence: The universe is wonderful and real!
Earlier in this chapter we discussed the limitations
of information obtained through our
senses because senses can be deceived. The
Chinese philosopher Chuang Tsu illustrated
the dilemma with the following story:
Once upon a time, I, Chuang Tsu, dreamed I
was a butterfly, flying happily here and there,
enjoying life without knowing who I was.
Suddenly I woke up and I was indeed Chuang
Tsu. Did Chuang Tsu dream he was a butterfly
or did the butterfly dream he was Chuang
Tsu 1
Perhaps you, too, have had dreams that
were so vivid that after awakening you were
puzzled for a moment about what was real. In
essence the assumption of existence asserts that
Chuang Tsu is, indeed, a Chinese philosopher
and not a butterfly, and the reality around him
is the same as the reality that surrounds us. Each
of us might see this reality a little differently
because of who we are. But regardless of how
we understand it, a single, unique,
reality is there, existing independent
of us.
2. Causality: Events in the physical
universe have natural causes.
Causes precede the events in
time and can be explained
rationally in terms of the laws of
nature.
Science has never proven that it
is impos sible to travel back in time.
However, someone traveling to the
past could possibly kill their own par-
Existence
The fact or state of having
actual or real being.
Causality
Cause must always precede
the effect.
figure 1.7
Causality: The apple cannot burst before the
bullet strikes it.