Biology in the popular mind remains tied to the doctrines of the struggle forsurvival and the survival of the fittest. Physics is linked to the heat deathof the universe – the inexorable march towards greater disorder,increasing entropy. Our field, on the other hand, focuses on orderedstructures, molecules and crystals, and their aggregates, and what holdsthem together. The philosophy of chemistry is centered on affinity,cohesion, the architecture of the very small, attraction, harmony, and, ifyou permit, beauty. Our discipline is the voice (...) of the twenty-first century,a message, a clarion call of life, of hope. This paper addresses failures ofreductionist and deterministic claims in the face of the cussedness ofchemical facts. It will examine uncertainty principles, Edmund Whitaker'spostulates of impotence, Gerald Holton's themata, Isaiah Berlin's warning –and the wisdom of the Chinese. We can teach the world the need for humilityin the face of the wonder and mystery of our world. (shrink)

Because of its elegant simplicity, the Arabidopsis root has become a model for studying plant organogenesis. In this review we focus on recent results indicating the importance of signaling in root development. A role for positional information in root cell specification has been demonstrated by ablation analyses. Through mutational analysis, genes have been identified that play a role in radial pattern formation. The embryonic phenotypes of these mutants raised the possibility that division patterns in post‐embryonic roots are dependent on signaling (...) that originates during embryonic development. Analysis of expression of the SCARECROW gene indicates that it may play a role in this ‘top‐down’ signaling process. Characterization of root epidermis development has led to the identification of negative regulators of root‐hair formation. These appear to set up a prepattern which is reinforced by signaling by plant hormones. (shrink)