8-27-90 One of the more interesting letters I found while perusing Thomas Jefferson’s writings in the UTA library the other day concerns classification in natural history. In a letter to Dr John Manners dated 22 February 1814, Jefferson writes:
Nature has, in truth, produced units only through all her works. Classes, orders, genera, species, are not of her work. Her creation is of individuals. No two animals are exactly alike; no two plants, nor even two leaves or blades of grass; no two crystallizations. * * * This infinitude of units or individuals being far beyond the capacity of our memory, we are obliged, in aid of that, to distribute them into masses, throwing into each of these all the individuals which have a certain degree of resemblance; to subdivide these again into smaller groups, according to certain points of dissimilitude observable in them, and so on until we have formed what we call a system of classes, orders, genera and species. In doing this, we fix arbitrarily on such characteristic resemblances and differences as seem to us most prominent and invariable in the several subjects, and most likely to take a strong hold in our memories.
I agree with Jefferson that there are no classification schemes in nature. Nature is a mass of individuals. Schemes are imposed on nature by rational beings for various purposes, some practical and some not so practical. My only disagreement with Jefferson concerns the basis of the classification. Jefferson seems to think that any such classification scheme is arbitrary—that the only basis for preferring one scheme to another is that it is easier to remember. Actually, ease of memory isn’t the only desideratum. As Irving Copi [1917-2002] points out in Informal Logic, one scheme can be more fruitful than another in suggesting explanatory hypotheses. But this is a quibble. Jefferson anticipated by at least 174 years the work of Nelson Goodman, whose book Ways of Worldmaking [Indianapolis: Hackett Publishing Company, 1978] suggests that worlds are created rather than discovered.
Keith Burgess-Jackson, J.D., Ph.D. 