If the misery of our poor be caused not by the laws of nature, but by our institutions, great is our sin. - Stephen Jay Gould

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.”

When scientists need to explain difficult points of theory, illustration by hypothetical example - rather than by total abstraction - works well (perhaps indispensably) as a rhetorical device. Such cases do not function as speculations in the pejorative sense - as silly stories that provide insight into complex mechanisms - but rather as idealized illustrations to exemplify a difficult point of theory. (Other fields, like philosophy and the law, use such conjectural cases as a standard device.)

Christopher Wren, the leading architect of London's reconstruction after the great fire of 1666, lies buried beneath the floor of his most famous building, St. Paul's cathedral. No elaborate sarcophagus adorns the site. Instead, we find only the famous epitaph written by his son and now inscribed into the floor: “si monumentum requiris, circumspice”—if you are searching for his monument, look around. A tad grandiose, perhaps, but I have never read a finer testimony to the central importance—one might even say sacredness — of actual places, rather than replicas, symbols, or other forms of vicarious resemblance.