making sense of it all
Connections Made
In one of my favorite jokes, a man goes into a movie theater and is surprised to see a woman enter
with a dog. When the movie starts, the dog watches it, laughing at the funny parts, crying at the sad
parts, and bouncing up and down at the exciting ending. When the movie finishes, the man chases after
the woman and says: “Excuse me, I was amazed that your dog actually seemed to be enjoying the
movie.” The woman responds: “I was surprised too—he hated the book.” Like most jokes, this one is
funny because it sets up one coherent set of expectations and then violates them in another coherent
direction. Jokes make sense in surprising ways.
Scientific and philosophical explanations are not generally funny, but they also achieve coherence
in surprising ways. I have tried to pursue an integrated approach to what I take to be the four most
important philosophical problems: What is reality? How do we know it? Why is life worth living?
What is right and wrong? Coherence comes in part from a commonality of method, relying on
evidence drawn from observations and scientific experiments rather than from religious faith, a priori
arguments, or thought experiments. I have tried to keep in mind the Jewish proverb “For example is
not proof.” Anecdotes are at best a weak form of evidence, and the made-up thought experiments
favored by many philosophers are not evidence at all.
I have used more systematic forms of evidence to argue for two main claims about reality, that
minds are physical systems constituted by brains interacting with bodies and the world, and that the
world exists independently of anyone's mind. We know reality not just by collecting the results of
observation and experiment, but also by forming theories that we can evaluate to see whether they are
part of the best explanation of the full range of available evidence. Scientific theories such as
Newtonian mechanics, electromagnetism, and the germ theory of disease have been hugely successful
in enabling humans to interact with the world, providing strong indication that the method of
evidence-based inference is far more effective than methods based on faith or intuition.
Similarly, scientifically collected evidence can aid us in developing the kinds of normative
theories we need to answer questions about ethics and the meaning of life. There is no simple leap
possible from “this is how things are” to “this is how things should be,” but evidence is nevertheless
highly relevant to questions of value. Such relevance is most easily seen in instrumental reasoning,
where something is assigned value because it is a way of achieving something else already identified
as valuable. For example, if we value truth, and scientific method is a good road to truth, then
scientific method can also be valued. The main problem is how we manage rationally to assign value
to our top-level goals, such as truth and explanation. I have ruled out any transcendent, a priori
arguments for such goals, so it might seem that one must be either arbitrary or circular in defending
them.
I have tried to show that coherence of goals with each other and with various kinds of evidence
provides a middle way between arbitrariness and circularity. Just as scientific theories and
experiments are justified because of their fit with each other, similarly we can look for general
descriptive and normative accounts that are justified because of their mutual coherence. The specter
of circularity is avoided through the relative objectivity of evidence collected through the senses,
which we know to be generally reliable because of past experience and growing scientific
understanding of the underlying physical mechanisms by which vision, touch, hearing, and smell
interact with the physical world. Sciences such as biology and psychology enable us to identify the
needs of human beings, which are the factors that enable us to operate as persons in our complex
physical and social worlds. Truth and explanation are such factors, because we cannot operate as
human beings without some reliable understanding of how the world works around us. Other
objective needs include material subsistence, autonomy, and social relatedness.
The easily recognized importance of such factors enables us to reject nihilism about the meaning of
life as well as the minimalist pursuit of slacker serenity. I have tried to show how it is possible to be
naturalistically normative about knowledge (chapters 2 and 4), the meaning of life (chapters 7 and 8),
and questions of right and wrong (chapter 9). Figure 10.1 provides a schematic summary of the use of
scientific evidence and theories to inform deliberation about the justification of practices through
their contributions to appropriate goals. We can use evidence to help us select theories and to identify
practices and goals, at the same time that evidence is influenced by theories, and practices and goals
are influencing each other.