Hylomorphic Elements and the Cell Theory: A Basis for Biological Law?

I am the vine, you are the branches. Whoever remains in me and I in him will bear much fruit.

(John 15:5)

THE CELL THEORY, also known as the cell doctrine, expresses the major biological insight that emerged in the wake of the invention of the microscope and the discovery of the structure of living organisms. The three tenets of the theory, formulated over a course of two decades in the mid-nineteenth century, are commonly articulated as follows:

1. 1. All living organisms are composed of one or more cells.

2. 2. The cell is the basic unit of life.

3. 3. Cells come from pre-existing cells.

The first two tenets of the theory were proposed by Theodor Schwann (1810–82) and Matthias Jakob Schleiden (1804–81), who initially thought that cells come to be by a process of crystallization of inorganic elements. That idea was later rejected by Robert Remak (1815–65) and Rudolf Virchow (1821–1902), who proposed the third tenet of the theory, establishing cellular generation as proceeding exclusively from pre-existing cells, a principle later translated as “Omnis cellula e cellula.”¹

To this day, biological observations remain in keeping with the tenets of the cell doctrine as enunciated a century and a half ago. However, ever since its first articulation, the doctrine has confronted scientists with nagging philosophical questions. For example, the cell theory has provoked disputes about the nature of the relationship between the cellular parts and the whole organism; it has prompted a search—so far fruitless—for more fundamental, subcellular loci of vital activity; and, to the frustration of biologists and philosophers wedded to a reductionist understanding of nature, it has suggested a realm of natural action among living species distinct from that of the inorganic elements.²

To my knowledge, the cell theory has not received an explicit treatment within a hylomorphic framework, that is, within the framework of natural philosophy established by Aristotle and further clarified by St. Thomas Aquinas. In this article, I will show that the cell theory points to a parallel between the properties of elements as explained by Aristotle and Aquinas, and the properties of cells revealed by modern biology. Such a parallel might prove helpful in firming up our philosophical understanding of biology and might guide further hylomorphic interpretation of modern empirical findings.

I. Hylomorphic Elemental Theory

An element is “the primary component immanent in a thing, and indivisible in kind into other kinds.”³ The hylomorphic account of nature establishes that the material world is made up of a noninfinite plurality of elements.⁴ Elements may exist as simple bodies, composites of prime matter and of an elemental substantial form,⁵ or be part of mixed bodies, which are composed of more than one element.

As simple bodies, elements have extension and may be divisible according to quantity: a body of water, for example, can be divided into parts by an efficient cause (say, a bucket) and each part of water is water. An element may corrupt, and corruption of an element leads to the generation of another element of a different kind.⁶

In a mixed body, the elemental substantial forms of the constituent elements cease to be in act, but the elemental powers are retained—albeit in an attenuated way.⁷ Accordingly, a body made up, for example, of a certain proportion of fire and water will manifest a certain heat and a certain moisture in proportion to the constituent elements, and this degree of heat and moisture will be the proper disposition for the substantial form of the mixed body.⁸ The phenomenon by which, in a mixed body, elemental substantial forms are not in act while elemental powers are retained is commonly referred to as the “virtual presence” or the “presence by power” of the element in the mixed body.⁹ It is because the elemental forms are not in act that contrary elements can coexist in the mixture, since otherwise it is impossible for contrary things (e.g., fire and water) to be in...