 An example for the vera causa ideal at work can be found in the history of genetics. In the 19th Century, there was much speculation about hereditary particles. For example, Darwin’s “provisional hypothesis of pangenesis” postulated freely circulating particles or “gemmules” that represented the parts and organs of an organism and transmitted this information to subsequent generations. While Darwin was himself an advocate of the vera causa ideal, which he meticulously applied to his theory of natural selection, he held this “provisional hypothesis” to less exacting standards (Stanford 2006). However, of course others criticized the pangenesis theory for its failure to meet the vera causa standard, because the gemmules were only inferred on the grounds that they could explain certain hereditary phenomena.