The Peripatetic theory of spontaneous generation is one of the foremost theories of the natural philosophy of classical antiquity. Having been accepted for two millennia, and only refuted as recently as the nineteenth century, it has proven to be a great legacy of Greek thought and its manifest reasoning. Its preeminence on the scientific stage has come to be as equally significant in the philosophical one, being embraced by materialist and idealist thinkers alike, as well as those on both sides of the theological-Darwinist divide. This paper seeks to examine how Theophrastus’ rehearsal of the theory of spontaneous generation illustrates the activities and philosophical orientation of the Peripetatic school. The paper first examines the historical context of the theory, before unpacking its theoretical and methodological background. The analysis concludes with an investigation of Theophrastus’ espousal of inductive reasoning.
The first thing to say about the theory of spontaneous generation is that it did not spontaneously generate from Theophrastus’ intellectual or for that matter, physical, wanderings. Rather, it emerged from a fertile context of Aristotelian thought. Indeed, Theophrastus did not have to wait until Plato’s death to furnish himself a disciple of Aristotle, for the latter’s riveting metaphysical and biological investigations had piqued the young philosopher’s mind. For thirty-five years thereafter, Theophrastus, following in his teacher’s steps, ruled the Peripetatic school, taking thinkers as varied as Eudemus of Rhodes, Aritoxenus of Tarentum, Strato of Lampsacus, Demetrius of Phalerus, Alexander of Aphrodisiae, Aristocles of Messene, Philoponus, Simpliclus, and Galen, not to mention the 2,000 others, under his wing. Theophrastus, one could say, was to Aristotle what Paul of Tarsus was to Christ. These successors of Aristotle, however, had left much to be desired. As Cicero liked to say, they were ‘so inferior to their forebears that you would have thought they had given birth to themselves’. Fortunately, however, because it was Theophrastus who enumerated the theory and not his successors, we do not have to worry about the coherence and philosophical integrity of the theory, as we would have otherwise, given Cicero’s unease.
As far as theoretical underpinnings are concerned, the Aristotelian theory of hylomorphism is most germane to the assessment at hand. The idea is that all livings things derive from form (given by the father) and matter (given by the mother), a rejection of the prevailing Hippocratic view which held at the time that the father and mother contribute to the embryo in similar fashion. For Aristotle, the father’s role is necessary, while the mother’s is sufficient. That is to say, the father’s role is a necessary condition for life, while the mother’s is a sufficient one. Of course, today it is widely acknowledged that the reality approximates the Hippocratic view, as male testes and female ovaries play mutually necessary roles. However, the hylomorphic theory is of particular interest with regards to those instances where such offspring emerge from non-living entities, and most specifically, where these entities are plants as opposed to animals. We should not be quick to draw a parity here, however. ‘Plants,’ as Aristotle noted, ‘must be investigated separately’. Nevertheless, this is the problem which Theophrastus, and by extension we, are concerned with.
Having laid the context out of which Theophrastus’ concerns emerged, we might like to now examine the Peripatetic activities and philosophical orientations his passage betrays. The preoccupation with natural philosophy is the most obvious place to begin. The Peripatos, following Aristotle, viewing philosophy as first and foremost a science, were privately contemptuous of other areas like ethics, aesthetics, and social-political philosophy. That is not to say they did not study such subjects. On the contrary, great works were written about them by the Peripatos, but not in their own right or on their own terms. Moral subjects, for instance, were considered rational beings, a precursor perhaps to the models of economic agents we see today (see Sharples (2010, p. 111-133)). In any case this scientific, laser-like disposition makes itself clear in phrases where Theophrastus draws corollaries of necessity, as when it is stated that: ‘it is a necessary consequence that x if they are not y’; implicates relations of logic and induction when he states ‘perhaps it is not true that x, the truth being that we fail to observe y’; and forthrightly upholds the skeptical mindset of a scientist: ‘but this kind of generation is somehow beyond the ken of our senses’. Such a methodological liking to science is not just established here, but forms part of a broader agenda of inquiry common to all of Theophrastus’ writings, and those of the Peripatos more generally.
As has been discussed, the thoroughgoing style and inquisitive nature of Theophrastus and his Peripatetic school is clearly attributable in the Enquiry Into Plants (or Historia Plantarum). This is attested to by the painstaking study that we readers do not see. Theophrastus’ careful investigations of over 550 species of plants went into the production of this work, as well as the measurements and evaluations of associated variables, as complex as the climate, the types of wood involved, the evolution of the plants through time, and the diversity of their species around the world. This approach to research is also telling for another reason: it highlights the school’s commitment to induction. Whereas the Platonists would privilege their deductive faculties—reasoning from the general (e.g. the Forms) to the specific (e.g. individuals)—the Peripatetics, and to a lesser extent Aristotle, extrapolated from the specific to the general. Here this approach appears in a subtler guise, as when Theophrastus infers from the history of the Willow and the elm that it may be the case all larger plants grow from seed save our failure in observing it; or when he extrapolates from the set of plants he has examined the act of spontaneous generation to the class of the fruitless trees.
Under Theophrastus, the Peripatetics developed a keen empiricist grounding, and this skepticism of Aristotle’s teleological approach to nature is unequivocal when one reads his passage on spontaneous generation. As we have seen there exists a great historical as well as conceptual background that underpins the evolution of the theory of spontaneous generation. But this was something that was always going to compromise its standing to 21st century responders, given its contingency on the findings of the time which, as wide-ranging and universal as they had hoped for them to be, were never really sufficient to safeguard the theory from the scorn of future generations. Yet it was just this philosophical vulnerability that secured them the final embedment, as their unparalleled diligence, and polymathic vigor, saw the theory rule for some two millennia.
Sharples, R.W. 2012. Peripetatic Philosophy, 200BC to AD200: An Introduction and Collection of Sources in Translation, Cambridge: Cambridge University Press.