Scio: tu coactus tua voluntate es.
I know it; you are constrained by your inclination.

A complete theory of evolution must acknowledge a balance between ‘external’ forces of environment imposing selection for local adaptation and ‘internal’ forces representing constraints of inheritance and development. Vavilov placed too much emphasis on internal constraints and downgraded the power of selection. But Western Darwinians have erred equally in practically ignoring (while acknowledging in theory) the limits placed on selection by structure and development–what Vavilov and the older biologists would have called ‘laws of form.’

A free soul ought not to pursue any study slavishly; for while bodily labors performed under constraint do not harm the body, nothing that is learned under compulsion stays with the mind.

A social fact is every way of acting, fixed or not, capable of exercising on the individual an external constraint; or again, every way of acting which is general throughout a given society, while at the same time existing in its own right independent of its individual manifestations.

Historically, science has pursued a premise that Nature can be understood fully, its future predicted precisely, and its behavior controlled at will. However, emerging knowledge indicates that the nature of Earth and biological systems transcends the limits of science, questioning the premise of knowing, prediction, and control. This knowledge has led to the recognition that, for civilized human survival, technological society has to adapt to the constraints of these systems.

Iconography becomes even more revealing when processes or concepts, rather than objects, must be depicted–for the constraint of a definite ‘thing’ cedes directly to the imagination. How can we draw ‘evolution’ or ‘social organization,’ not to mention the more mundane ‘digestion’ or ‘self-interest,’ without portraying more of a mental structure than a physical reality? If we wish to trace the history of ideas, iconography becomes a candid camera trained upon the scholar’s mind.

It is tautological to say that an organism is adapted to its environment. It is even tautological to say that an organism is physiologically adapted to its environment. However, just as in the case of many morphological characters, it is unwarranted to conclude that all aspects of the physiology of an organism have evolved in reference to a specific milieu. It is equally gratuitous to assume that an organism will inevitably show physiological specializations in its adaptation to a particular set of conditions. All that can be concluded is that the functional capacities of an organism are sufficient to have allowed persistence within its environment. On one hand, the history of an evolutionary line may place serious constraints upon the types of further physiological changes that are readily feasible. Some changes might require excessive restructuring of the genome or might involve maladaptive changes in related functions. On the other hand, a taxon which is successful in occupying a variety of environments may be less impressive in individual physiological capacities than one with a far more limited distribution.

It is we, we alone, who have dreamed up the causes, the one-thing-after-another, the one-thing-reciprocating-another, the relativity, the constraint, the numbers, the laws, the freedom, the ‘reason why,’ the purpose. ... We are creating myths.

Life is inseparable from water. For all terrestrial animals, including birds, the inescapable need for maintaining an adequate state of hydration in a hostile, desiccating environment is a central persistent constraint which exerts a sustained selective pressure on every aspect of the life cycle. It has been said, with some justification, that the struggle for existence is a struggle for free energy for doing physiological work. It can be said with equal justification for terrestrial organisms that the struggle for existence is a struggle to maintain an aqueous internal environment in which energy transformations for doing work can take place.

Scientists who dislike constraints on research like to remark that a truly great research worker needs only three pieces of equipment: a pencil, a piece of paper and a brain. But they quote this maxim more often at academic banquets than at budget hearings.

We do not inhabit a perfected world where natural selection ruthlessly scrutinizes all organic structures and then molds them for optimal utility. Organisms inherit a body form and a style of embryonic development; these impose constraint s upon future change and adaptation. In many cases, evolutionary pathways reflect inherited patterns more than current environmental demands. These inheritances constrain, but they also provide opportunity. A potentially minor genetic change ... entails a host of complex, nonadaptive consequences ... What ‘play’ would evolution have if each structure were built for a restricted purpose and could be used for nothing else? How could humans learn to write if our brain had not evolved for hunting, social cohesion, or whatever, and could not transcend the adaptive boundaries of its original purpose?

When Bonner writes that ‘natural selection for optimal feeding is then presumed to be the cause of non-motility in all forms,’ I can’t help suspecting that some plants might do even better if they could walk from shade to sun–but the inherited constraints of design never permitted a trial of this intriguing option.

Why do the laws that govern [the universe] seem constant in time? One can imagine a Universe in which laws are not truly law-full. Talk of miracle does just this, invoking God to make things work. Physics aims to find the laws instead, and hopes that they will be uniquely constrained, as when Einstein wondered whether God had any choice when He made the Universe.