Biology Reference
In-Depth Information
danger invariably arises from the ruthless application, on a vast scale, of partial
knowledge' (Schumacher, 1973), should we not be asking ourselves seriously
whether we can we really explain life? How successfully can we at present
answer the questions 'why
Escherichia coli
?', 'why
Homo sapiens
?', 'why any
organism?
Organisms as we know them are material systems, and according to Aristotle
(1998, 350 B.C.E) there are four different ways of answering 'why'-questions
about material objects, questions that he placed at the heart of science. Put
differently, there are four fundamentally different explanatory factors that
together explain any object fully.
4
These four
aitia
, as he called them, are now
commonly described as material, efficient, formal and final causes. However,
to avoid confounding Aristotelian explanations with 'causation' in the sense of
Hume, Cohen's suggestion
5
to replace the noun 'cause' with the verb 'make' is
useful:
(1) What is an organism made out of? (its material cause)
(2) What makes (in the sense of '
what is it to be
') an organism? (its formal
cause)
(3) What makes (in the sense of '
what produces
') an organism? (its efficient
cause)
(4) What is an organism made for? What is its purpose or function? (its final
cause)
Biochemistry, molecular biology and molecular genetics have been spectacularly
successful in providing us with answers to the first two questions: (i) a century's
worth of research tells what organisms are composed of and what the structure
of their molecular constituents are, and (ii) after Watson and Crick biologists
generally ascribe, rightly or wrongly, the essence of an organism to its DNA.
These two answers explain life statically in terms of matter and form, and seem,
for many, to suffice.
However, Aristotle insisted that all four explanations are needed for full
understanding. The other two questions are questions of process and transfor-
mation; they explain why change occurs and lead to dynamic explanations.
Currently, biology's answer to the third question of what produces an organism
is essentially: 'its parent(s)'. Rudolf Virchow famously summed up this view as
cellula e cellula
(every cell from a pre-existing cell), a phrase actually coined by
4
In contrast with Humean doctrine in which effects and their causes are
events
, Aristotle typically considered
the causes of
substances
or
objects
; this approach is particularly applicable to artifacts, whether artificial or
natural. Living organisms are the ultimate natural artifacts (Barbieri, 2005).
5
Lecture on the four causes (http://faculty.washington.edu/smcohen/320/4causes.htm). To quote Cohen: 'Aris-
totle's point may be put this way: if we ask 'what makes something so-and-so?' we can give four very different
sorts of answer - each appropriate to a different sense of 'makes' '.
