1st article that shaped my career: “The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme” – Gould & Lewontin, 1979

Euclydes Santos used this article during his course ‘Physiological adaptations to estuarine environment’, in graduate school. I seriously doubt that, even with all the interest that I have for everything that is Gould’s or Lewontin’s, I would bump into it if it wasn’t for him. So, thank you (again) Euclydes

(The) adaptationist program (…) is based on faith in the power of natural selection as an optimizing agent. It proceeds by breaking an organism into unitary’ traits’ and proposing an adaptive story for each considered separately. Trade-offs among competing selective demands exert the only brake upon perfection; non-optimality is thereby rendered as a result of adaptation as well. We criticize this Approach

Gould & Lewontin, 1979

During undergrad, I learned that evolution is a tautology: if it is around, then it has been selected. However, you can never see evolution or natural selection in action. That means we cannot ‘experiment’ with natural selection and we can only ‘observe’ the effects of evolution, without ever testing it (well, we can actually do that with some microorganisms. But it is not quite the same think with complex organisms like fish and mammals). Thus, evolutionists were doomed to only observe evolution after the fact. And since one can always deduce a reasonable explanation to a past event, we could explain evolution anyway we wanted. Even with completely competing explanations. Even with crazy ideas. As long as they made sense, they all could be true. Right? More or less, said Gould e Lewontin.

“organisms must be analysed as integrated wholes, with blueprint so constrained by phyletic heritage, pathways of development and general architecture that the constraints themselves become more interesting and more important in delimiting pathways of change than the selective force that may mediate change when it occurs.”

Gould & Lewontin, 1979

This beautiful idea that organisms are limited by their past commitments with the environment was first introduced to me by this article. It is true it took me many years to really incorporate the idea. I had to go through a little of philosophy (deduction and induction logics) and doing so I had the pleasant surprise of learning about parsimony’s principle and ‘Occam’s razor’ a logical tool to decide among competing theories.

At the time, I already new that ‘natural selection’ was not all mighty, but this article was so interesting that I went back to learn more about genetic drift and neutral selection. This article made me want to learn more! Isn’t it great?! Isn’t the kind of article that you want to write?!

Another great feature of this article is the metaphor they use to example how twisted is the idea of explaining something based only on its use.

(At) the great central dome of St Mark’s Cathedral in Venice (…) each spandrel contains a design admirably fitted into its tapering space. An evangelist sits in the upper part flanked by the heavenly cities. Below, a man representing one of the four Biblical rivers pours water from a pitcher into the narrowing space below his feet. The design is so elaborate, harmonious and purposeful that we are tempted to view it as the starting point of any analysis, as the cause in some sense of the surrounding architecture. But this would invert the proper path of analysis. The system begins with an architectural constraint: the necessary four spandrels and their tapering triangular form. They provide a space in which the mosaicists worked. (…) Such architectural constraints abound and we find them easy to understand because we do not impose our biological biases upon them.

Gould & Lewontin, 1979

Needless saying how this paragraph impacted my first visit to St Mark’s Cathedral in Venice

According to the authors, the followers of the adaptationist program uses the following logics to explain any trait observation:

“If one adaptive argument fails, try another; If one adaptive argument fails, assume that another must exist (a weaker version of the first argument); In the absence of a good adaptive argument in the first place, attribute failure to imperfect understanding of where an organism lives and what it does; Emphasize immediate utility and exclude other attributes of form.”

Gould & Lewontin, 1979

And the authors found a ironic, although clear and intelligent way of expressing their strong disagreement and the risk of damage to their beloved field of study by comparing this arguments to those of the ridicule Dr. Pangloss, in Voltaire’s ‘Candide’, to whom even the worst of the events, helped for a good reason:

“Things cannot be other than they are … Everything is made for the best purpose. Our noses were made to carry spectacles, so we have spectacles. Legs were clearly intended for breeches, and we wear them.” Yet evolutionary biologists, in their tendency to focus exclusively on immediate adaptation to local conditions, do tend to ignore architectural constraints and perform just such an inversion of explanation.

Gould & Lewontin, 1979

Needless saying that because of this article I read Voltaire.

It is very, very important to establish your hypothesis in advance, before you start your experiments.

The article goes on and proposes evolutionists to have a new look over evolution:

1. No adaptation and no selection at all.
2. No adaptation and no selection on the part at issue; form of the part is a correlated consequence of selection directed elsewhere.
3. The decoupling of selection and adaptation. Selection without adaptation and Adaptation without selection.
4. Adaptation and selection but no selective basis for differences among adaptations.
5. Adaptation and selection, but the adaptation is a secondary utilization of parts present for reasons of architecture, development or history.

To finish, another important lesson I learned from it was that about the proper meaning of adaptation. Adaptation is genetic and there is no ‘physiological’ adaptation:

The good fit of organisms to their environment can occur at three hierarchical levels with different causes. It is unfortunate that our language has focused on the common result and called all three phenomena ‘adaptation’. (…) what physiologists call ‘adaptation’ (is) the phenotypic plasticity that permits organisms to mold their form to prevailing circumstances during ontogeny. Human ‘adaptations’ to high altitude fall into this category (…). ‘Physiological’ adaptations are not heritable, though the capacity to develop them presumably is.

Gould & Lewontin, 1979

Thus, they are not adaptations. They are acclimations.

I ask myself how have I ever decided the endpoint of an experiment without having clear what adaptation was (and thus, what could be an endpoint for a physiological stress response).

It may seem very ‘biology’, but the rational applies to science in general and that is why I urge you to read this article.