from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The act of shaping or forming in advance; prior formation.
  • noun A theory popular in the 1700s that all parts of an organism exist completely formed in the germ cell and develop only by increasing in size.

from The Century Dictionary.

  • noun Antecedent formation; shaping in advance.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Biol.) An old theory of the preëxistence of germs. Cf. emboîtement.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun Prior formation.
  • noun biology, historical The theory that organisms are fully developed in the form of an egg or seed, and just increase in size (as opposed to epigenesis.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a theory (popular in the 18th century and now discredited) that an individual develops by simple enlargement of a tiny fully formed organism (a homunculus) that exists in the germ cell


from Wiktionary, Creative Commons Attribution/Share-Alike License

From pre- +‎ formation.


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  • Wolff had risen up as an opponent of the so-called preformation theory, still widespread at that time, according to which the entire plant with all its different parts is already present in embryonic physical form in the seed, and simply grows out into space through physical enlargement.

    Man or Matter

  • I think that it is interesting that Behe has toyed with the idea of a kind of preformation of the DNA, with the genes for such-and-such being designed into the genome at the beginning and remaining hidden over the generations until they were expressed. nickmatzke

    The true origin of "intelligent design" - The Panda's Thumb

  • Specification of the primordial germ cells (PGCs) takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ( 'preformation') or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ( 'epigenesis').

    BioMed Central - Latest articles

  • Generation and growth were on his view, mechanical processes, for, according to the doctrine of preformation, which he shared with Malebranche, generation is just growth.

    Kant and Leibniz

  • The argument appears in an early form as an argument against embryonic development, and in favor of preformation.

    The true origin of "intelligent design" - The Panda's Thumb

  • Similarly, there is a “disposition, an aptitude, a preformation, which determines our soul and brings it about that [necessary truths] are derivable from it.”

    Gottfried Wilhelm Leibniz

  • Epigenesis and preformation offer two competing interpretations of what is involved, with a range of alternatives in between.

    Epigenesis and Preformationism

  • Thus, discussions of epigenesis and preformation often bring in other ancillary questions and are difficult to separate from their contexts.

    Epigenesis and Preformationism

  • Whitman felt that what biology needed was a clear statement of the alternative views, and then movement to a new standpoint examining how much depends on the organism's developmental response to external conditions drawing on preformation, rather than on programmed internal unfolding alone.

    Epigenesis and Preformationism

  • Yet typically discussions of epigenesis and preformation have focused on individual organisms and their development rather than on species.

    Epigenesis and Preformationism


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