38 The Free Will Problem
Although we regard F2 as an improvement over F1, we will return to formulat-
ing further problems just in terms of determinism rather than determinism. One
reason for this is because other philosophers tend to think about the free will
issue by working with puzzles formulated in terms of determinism strictly
defined. But another reason, as will become clear shortly, is that certain ways of
developing the problem involve careful expression of what possibilities are con-
sistent with an agent’s acting other than as she does. It is easier to think clearly
about these issues when we have a precise way of thinking about what physical
possibilities determinism leaves open, given the past and the laws. More permis-
sive theories of what is physically possible, as would be the case with almost-
determinism, mechanism, or naturalism, would not allow us to easily model
these physical possibilities. So, while F2 is an improvement over F1, we will
stick with F1 in order to simplify further issues. But readers should bear in mind
that a more accurate way of thinking about these issues ought to make room for
the apparent threat posed to free will not just by determinism but also by
determinism.
Now consider free will itself. What presumed features of acting freely appear
to be under threat by the contention that determinism is true? There are at least
two different ways to think about free will and about the free acts that are exer-
cises of it. Perhaps the most familiar and pervasive way to think of such freedom
is in terms of control over alternative pathways into the future, initiated by
alternative acts (broadly construed to include omissions). On this model, the
future can be pictured as a garden of forking paths. An agent’s relation to the
future, by way of her free will is a function of the leeway she has to act in ways
that involve taking different paths. True, a free agent’s future possibilities are
not unconstrained; the past and the laws of nature structure the potential range of
possibilities. But for a free agent, on this model, there is more than one, and the
agent has a kind of control over which ways, within these constraints, she might
act. Consider, then, Figure 2.1, representing the Garden of Forking Paths Model
and what we shall call leeway freedom.^9
The single, straight arrow to the left of the asterisk represents a free agent’s
past, moving from left (earlier) to right (later). Treat the dot itself as an “action
Past FutureFigure 2.1