Philosopher and chemist Michael Polanyi had an interest in what he called the "tacit" or "personal" knowledge that experienced scientists have of their subject. He was interested in intuition and moments of scientific discovery, such as the moment when Semmelweis realized that decomposing flesh contaminating the bloodstream of a healthy person must be the cause of childbed fever. Polanyi argued that when scientists lose control of their own research, when someone else restricts it to certain goals, science suffers and the outcomes are poor.
Polanyi also had a great interest in what he called "life's irreducible structure," arguing that life can't be reduced to basic physics. He first considered a machine, something made by humans to serve a purpose. The materials used to make a machine and the forces that drive it are derived from physical laws. It's not the physical laws that determine the function of a machine, but the way they are harnessed. There are two levels of control - the laws of nature and the higher level of the machine's design. This higher level of control, the boundary conditions, forms the constraints within which the laws of nature can act. One kind of boundary situation he called "test tube," where the focus is on the contents of the tube and not the tube itself. Polanyi called his second sort of boundary "machine-type," where the boundary rather than its contents are the focus. A diesel-powered machine can be fashioned to perform many different tasks. In art, the interest is not the medium, the paint or the musical notes, but the final form generated. The structure of an organism forms the boundary conditions within which the laws of nature work, but the boundaries can't be defined in terms of the laws they harness. The form transcends the laws it harnesses. Form doesn't follow function - green leaves come in many forms, but they all have the same function. Unlike a machine, an organism is self-generating. DNA forms the boundary conditions that harness the laws of information rather than energy.
To Polanyi, history replaces boundary conditions in processes such as geology, leaving natural laws as the single control. What happens today is constrained by what happened yesterday. But Jack pointed out that ontogeny and phylogeny are also strongly constrained by history. Perhaps evolution generates living structures through a combination of laws and organismal boundary conditions that include history. Organisms have functions, and those functions allow survival, but this is not sufficient to cause evolution. For living organisms, functional competence is a boundary condition. Phylogeny occurs in geologic or inferred time, while development takes place in real time, but both are evolutionary phenomena.
Boundary conditions are not the same as emergence, where the whole is greater than the sum of the parts, said Polanyi. Emergence is common in non-living as well as living systems. At some point life emerged from non-life and he believed this to be through the formation of boundary conditions. These were weak at first, but when bounded systems were able to persist beyond some threshold, they became able to capture energy and at some point replicate themselves. Hierarchies are common in nature and can be thought of as nested sets of boundary conditions where a higher level of the hierarchy relies on the principles established at lower levels, but the higher level can't be reduced to the lower. Language again - sound is shaped into words, words into sentences by grammar, sentences into paragraphs of a certain style. These levels can't be collapsed and they create multiple sources of control. There are new constraints at each level, limiting the scope of expression at the level beneath it. The highest level has the greatest control, like an organism controlling its parts. Leaves are made up of cells and tissues, but these don't dictate the form of the leaf As developmental time moves forward, potential forms an organism can take become more restricted. What happens in evolution limits, but does not determine, the form of a new species.
With evolution there is increasing complexity, in terms of more intricate life forms as well as new sorts of simple forms, such as bacteria. With increasing complexity, there are more boundary conditions, more restrictions, but this also leads to more potential novelty. Ecological hierarchies also exist. Since we first started classifying organisms, biologists have recognized the hierarchical organization of nature. Populations are best seen in the context of an ecological hierarchy (rather than an evolutionary one) where the interest is in the flow of matter and energy through a collection of co-existing life forms.
Ludwig von Bertalanffy began developing his General Systems Theory in the 1930s, setting out principles of hierarchical organization. His interest was in systems that are open to the flow of energy, such as organisms, but he was pointing out a set of shared uniformities instead of offering an explanation. Chaos and catastrophe theory, fractals and dynamical systems - these identify regularities in nature, but they lack a full theoretical basis.
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