Biology Reference
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or macromolecular behavior. We are, instead, elaborating on the structure and
dynamics of the system. Thus,
(3) We have to find the set of processes and parts to be referred to in the
mechanistic explanation and to move toward the corresponding grade of
resolution to redescribe the cellular behavior.
Of course, with a reduced tolerance, we may not be able to produce any expla-
nation without proceeding to a greater degree of resolution. The tolerance is a
matter of the empirical flexibility allowed in describing a behavior for a system.
The resolution is a matter of the descriptive flexibility in describing the mecha-
nisms. As we increase the resolution, we may predict the behavior more exactly,
but that also means we lose generality. As we decrease the resolution, we may
predict the behavior less exactly but increase generality. The scope or generality
is what is captured in the idea of tolerance.
(4) We articulate the mechanism corresponding to the behavior.
In Fig. 2, the behavior of cells is represented as being redescribed as behavior
of molecular systems, whereby we use a higher grade of resolution, say G
3.
This is not a shift in the level of organization or explanation. We are still dealing
with cells, not with isolated pathways or isolated enzymes. We just describe the
cells in greater detail, i.e., with a higher degree of resolution.
For example, for its maintenance
E. coli
needs a source of energy - sugars are
good carbon sources; to explain how it uses sugars we need to see what happens
−
Grades of resolution
G-3
G+1
G G-1
Example:
cellular behavior to be mechanically explained
Level of single cells
Behavior of cells as behavior of molecular systems
L+1
L
L-1
L-3
Behavior to be explained is at L
Grade of Resolution is at G-3
Figure 2
Changing grades of resolution, within a level of organization.
We may focus on some characteristic behavior of cells, describing cells as functional units; or we
may think of cells as molecular systems. Other grades of resolution are possible.
