Meeting 1.7 – Cause, Effect, and Intent in Biology


Mayr, Ernst. “Cause and Effect in Biology.” Science 134, no. 3489 (November 10, 1961): 1501–1506.


Summary:  Lucas Mix presented a summary of Mayr’s arguments.

Can life be causally explained by physics and chemistry? Descartes over-mechanized life, to which there was an over-reaction in vitalism. ‘1870 Helmholtz postulated “that the behavior of living cells should be accountable in terms of motions of molecules acting under certain fixed force laws.”’

Three elements of causality:

explanation (past), prediction (future), teleology (“goal-directed” behavior).

Two branches of biology:

Functional Biology: Structural questions, experimental methods, using isolation, asking “How?” [In what manner?] Biochemistry [Molecular and Cellular Biology, Physiology]

Evolutionary Biology: Historical and dynamic questions related to change, asking “How come?” but not “What for?” [For what reason? Not To what End?], [Organismic and Evolutionary Biology, Ecology]

Four causes in biology:

Ecological cause: based on environmental constraints [Reaching for history, contra #3, Universal?]

Genetic cause: based on inherited, coded information

Intrinsic and Extrinsic Physiological causes: based on immediate stimuli [The difference is unclear.]

The first two are ultimate causes, the last two proximate causes.

Individuals can be goal-directed because historical processes have made them so, but historical processes cannot be goal-directed.  It is “a purely mechanistic purposiveness” responding to inputs. [Can you call response purpose?]

Pittendrigh introduced teleonomic as a descriptive term for all end-directed systems ‘”not committed to Aristotelian teleology.”’ This is confusing.  Mayr proposes apparent purposefulness of “programmed” individuals. [Is the difference in intent?]

Prediction in Biology is problematic.  Mayr differentiates between issues of predicting observations and predicting outcomes.  The latter is highly statistical and indeterminate due to randomness, uniqueness, complexity, and [weak] emergence.

“The harmony of the living universe, so far as it exists, is an a posteriori product of natural selection.” Apparent order comes from evolution.



Discussion largely centered on questions of intent and purpose.

1) Does purpose require intent?

We talked about Mayr’s use of the “goal-directed” along with Aristotle’s “entelechy”, Aquinas’ “final cause”, and Monod’s “projective.”  Some aspect of future states causing present events seems out of bounds for science, as does some aspect of intentionality arising within natural forces.

Mayr seems to be suggesting that what we call “intent” in individuals exists, but results as the product of non-intentional forces.

As a group we were divided on whether there was some other meaning to intent other than the naturalized intent of Mayr.

2) What constitutes intent?

Roger White suggested that humans have intent in a way that yeast do not.

Lucas Mix and Riccardo Manzotti were unclear on exactly what that could mean other than more complex mechanisms for converting external stimuli to behavioral responses.

The question was raised as to whether intent should require some idea of internal representation or internal causation.  (See Lucas’ essay on “Intent and Biology” for some possibilities.)

Both questions 1 and 2 relate to an overall theme of the semester about aligning biological knowledge with knowledge in general.  How do biological concepts of intent align with common sense ideas of intent?  Does biological naturalism entail a constriction of “intent” and is that constriction acceptable?


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