Theory of Generation

Answers

• Q09LIFE

  Can the development of an organism from an egg be explained as the operation of a machine?

  No. development needs a formative force. Argues against preformation that the embryo forms by epigenesis from unorganized matter, and attributes the forming to an essential force (vis essentialis) rather than to a pre-built mechanism.

  Experimenta scilicet huius auctoris omnia eo concurrunt, ut confirment generalissimam Aristotelis veritatem: datur in rerum natura vis productrix; praeterea vero nihil determinant. Harveius in solo eo ab Excell. Ludwig et reliquorum recepta sententia differt, ut principium, unde generatum generanti simile efficitur, id est, rationem sufficientem compositionis corporis organici, in aliquam impressionem idealem, utero a semine masculino factam, ponat, analogam illi, quae, in cerebrum facta, artifex opera producit, illis obiectis, impressionem ipsi excitantibus, similia (vid. Exercit. de gen. animal. sect. de Conceptione); cum reliqui in mechanismum potius corporis organici generantis illud principium determinans posuerint. §. 233. Primum igitur generationis principium, et quo agente omnia efficiuntur, est illa vis motrix, quam essentialem denominavi, plantis et animalibus vivis necessaria, a pluribus, licet non tamquam principium generationis, dudum iam cognita.

  The experiments of this author [Needham] all tend to confirm Aristotle's most general truth: there is a productive force in nature; beyond that they determine nothing. Harvey differs from the opinion received by the excellent Ludwig and the rest only in placing the principle by which the offspring is made like the parent, that is, the sufficient reason for the composition of the organic body, in an ideal impression made on the womb by the male seed, analogous to the one by which, made on the brain, a craftsman produces works like the objects that excite the impression; whereas the rest placed that determining principle rather in the mechanism of the generating organic body. The first principle of generation, then, by whose action everything is brought about, is that moving force which I have named essential, necessary to living plants and animals, and long known to many, though not as the principle of generation.

  OCR correctedmachine translation

  Halle dissertation 1759; vis essentialis confirmed in Wikipedia and ASU Embryo Project; Internet Archive copies listed in search results.