Mechanisms Versus Causes in Biology and Medicine - Mechanism and Causality in Biology and Economics - page 24

order, rate, duration, and sphere of influence more or less independently of the
entities that engage in those activities.
A specific kind of activity produces a specific kind of change. Finding necessary
and sufficient conditions to characterize the many diverse kinds of production is
difficult and not required for their scientific discovery (Bogen 2008 ). Rather than
seeking a general definition of production, it is more insightful to consider specific
kinds of activities and the means for discovering them. As Machamer suggested in
MDC, human beings directly experience many kinds of activities, such as collision,
pushing, pulling, and rotating—the activities in mechanisms often discussed in the
seventeenth century. Scientists have since discovered many kinds of activities not
directly detectable by human senses, such as attraction and repulsion, electromag-
netism, and movements across membranes to achieve equilibrium. Science students
must be trained to understand how these activities work so that, with education,
they can “see” (understand) how mechanisms employing them operate.
Moving beyond what MDC claimed about activities and causes, I note that
relating “C causes E” to mechanisms may call attention to some piece of a
mechanism other than an activity. As Stuart Glennan ( 1996 ) notes, analysis of
“C causes E” may require an entire underlying mechanism to lay out all the stages
between C and E. In such a case, C refers to the entire mechanism at a lower
mechanism level. Alternatively, C may refer to an early stage of the mechanism
(consisting of entities and their activities) with the other stages between C and E left
unspecified. Hence, “cause” may refer to nearer or more distant stages in the
mechanism, prior to the stage (E) of interest.
In addition to entities and activities and organization, MDC noted that
mechanisms have “start or setup conditions.” If a mechanism requires a signal or
start condition (some don't, e.g., some biological mechanisms run continuously),
then that may be called a “triggering cause” or a “sufficient cause.” When the
trigger is present (and the set conditions are available), the mechanism begins to
operate. Something called a “necessary cause” might be any nonredundant part of
the mechanism or, instead, part of the setup conditions for a mechanism to operate.
Setup conditions for mechanisms are many and varied. Although some of the setup
conditions are known and indicated (such as in the materials and methods sections
of scientific papers), they cannot be fully specified, even in controlled laboratory
conditions. (This issue is well known in discussions of ceteris paribus conditions.)
My goal in this section thus far has been to try to map the C of “C causes E” onto
some piece of a mechanism or to its start or setup conditions. Now let's turn to E,
the effect. Presumably that corresponds to the phenomenon of interest. An impor-
tant starting point for finding a mechanism is to characterize the puzzling phenom-
enon that the mechanism produces (on recharacterizing the phenomenon as
research on the mechanism proceeds, see Bechtel and Richardson 2010 ). Presum-
ably, the characterization of the effect is similarly important in constraining ade-
quate claims about its cause.
One of the aims in finding causes is to enable humans to exert control. As is
sometimes said, a cause is a handle that can be turned to do something. What we
wish to control is E, the outcome. The goal of control of the outcome is especially