Guest post by Benny Goldberg from the Department for History and Philosophy of Science, Pittsburgh
Both Aristotle and Galen emphasize that, in order to achieve knowledge, one must make sure one is working with right sort of premises. And, for both, experience is the source of these premises. Anatomy, then, is the way in which one makes sure that the concepts in your premises are adequate to the phenomena: it is a process of definition, remembering that definitions for Galen and for Aristotle are accounts of the essences of those things (and, further, for both these authors and for Harvey, these essences are ultimately teleological, that is, they reveal what the thing being defined does). Here I will discuss the Galenic side of things, and in the next post I will discuss Harvey’s Aristotelian heritage.
Key, I think, to understanding the Galenic notion of experience are what he calls the ‘natural criteria’—these are the criteria by which we judge the similarity and differences in things such that we can define and understand them, or, to put it another way, to make sure our concepts are adequate to the natures of their subjects. We will return to the natural criteria in a moment, but let us first locate the origin of this idea in a particular text of Galen’s, namely his De placitis hippocratis et platonis, a work which I believe exerted a powerful influence over Harvey’s conception of experience and anatomy (here in the 1549 edition of the Opera Omnia) The De placitis was newly available to Western physicians in Humanist translations around the start of the sixteenth century, and was of fundamental importance in the renewal of anatomical practices by Vesalius and others, and was a key methodological text for physicians in training. This text places fundamental importance on anatomy as the prime method for investigating the soul of animals. Galen was a serious student of Aristotle’s works, and, as Teun Tieleman has argued, part of Galen’s criticism of the Peripatetics was just that some of their views on the soul (their cardiocentrism) were refuted by means of their own doctrines and methodologies! (Teun Tieleman 1996, Galen and Chrysippus on the Soul, 5. See Galen, De placitis, Lib.I, Cap.8) We should note that, though we have very little evidence regarding them and their doctrines, Galen was highly influenced by contemporary schools of Peripatetics, even and especially on his methodological doctrines.)As Galen writes,
…when Aristotle and Praxagoras affirm, contrary to anatomical observation, that the heart is the source of the nerves, they deserve to be censured. One can learn from the treatises they left that they observed with precision many other anatomical matters; but when they wrote about the source of the nerves, either they were completely blind themselves or they were addressing a blind audience. (Galen, De placitis, Lib.I, Cap.6)
So, to Galen at least, what he proposed methodologically was in agreement with Aristotle, even though the in terms of specific doctrines, Galen disagrees with the Philosopher. For Galen, experience provides the source of the premises used in demonstrations. In De placitis Lib.II, Galen argues that the problem with many demonstrations (those of Chrysippus especially) is that they use the wrong kind of premises. As Galen argues, the premises that are needed in this case are scientific premises, that is, those premises that pertain to the subject under investigation itself, as a substance. In other words, what are needed are premises that pertain to the essence of the subject under investigation. Above we saw that this, indeed, was what anatomy revealed for Harvey: the uses and actions which we understood as giving the essence of the parts of the body under investigation. So, for both Galen and Harvey, experience is the source of these premises. Galen in Lib.II goes over 4 sorts of experience, which are the following
What is evident to the mind
As Tielman has noted, Galen argues that to understand the parts of animals, simple sense perception and everyday experience are of quite limited use, and what is evident to the mind cannot resolve the issue (Tielman’s discussion of these notions is really wonderful, and I recommend anyone who is interested in Galen to read his work.) What is needed is technical experience, that is, experience gained through the art (techne) of anatomy.
Let us now return to the natural criteria. Galen describes the natural criteria in the following way:
Eyes in their natural state seeing what is visible; ears in their natural state hearing what is audible; the tongue sensing savors, the nostrils odors, the whole skin objects of touch; and besides, thought or mind or whatever you wish to call it, by which we distinguish entailment and incompatibility and other things that pertain to them, such as division and collection, similarity and dissimilarity…. (Galen, De placitis Lib.IX, Cap. 1 )
In De methodis medendi, Galen notes that the Ancients recognized two classes of evident things: those evident to the senses, hot, cold, pale, dark, etc, and those evident to the intellect, equality, similarity, causes, etc. But what is key to note here is that the senses and the mind are not strictly separated here in Galen, and thus experience and reason go hand in hand: in order to, as Galen notes, ‘distinguish entailment and incompatibility’ one must use the mind, reason. Sensation and intellection are the very criteria by which we can achieve scientific knowledge. One without the other can result only in Sophistry.
In just the same way, Harvey seems to endorse a picture of anatomy that unifies reason and experience as part of one and the same process. The art of anatomy is one of hand and mind, and, further, one that takes a lot of training and experiencing in order to perfect: it is a facultas a skilled ability to cut and see and understand the parts of animals. (Anyone who has performed a dissection can tell you that the insides of people look nothing like the neatly labeled diagrams in anatomy textbooks!)
I want to end this post by connecting up this last point, about experience, reason and similarities and differences to something that might otherwise be mysterious in Harvey: his regula Socratis, his invocation to use the ‘rule of Socrates.’ This is a phrase that, so far as I can tell, does not appear in any other work by Harvey or anyone else. Harvey only uses the phrase twice in his Prelectiones, but, despite this, the rule of Socrates is central to his methodology over the course of his whole career.
The phrase occurs in Harvey’s ‘Canones anatomae generalis,’ which are a set of suggestions and heuristics for the proper performance of an anatomy. In his fifth canon anatomae generalis, Harvey exhorts students:
To review one’s own and another’s observations to confirm your own opinion, or in the strictest form, deal with other animals according to the rule of Socrates: where it is farer written. Whence exotic observations:
about the causes of disease: chiefly useful to the physician
about the variety of Nature: [chiefly useful] to the philosopher
for the purpose of refuting errors and solving problems
for the purpose of discovering uses and actions, excellences, and thus also on account of these, their classifications
The end of an anatomy is knowledge of a part, its purpose, its necessity and use. Its [anatomy’s] chief purpose for Philosophers is to learn which [parts] are required for each action insofar as it is excellent. Likewise [its chief purpose] for Physicians is [to learn] the natural constitution [of the parts], [that is] the standard by which they must classify those who are sick, and then what they must do in diseases.
“Observationes proprias et alienas recensere ad confirmandam propriam opinionem vel obsignatis tabulis in aliis animalibus agere secundum Socratis regulam: where it is farer written. Unde observationes exoticas:
ob causas morborum: medicis praecipue utilis
ob varietatem Naturae, philosophicis
ad refutandos errores et problemata solvenda
ob usus et actiones inveniendas dignitates et propter inde colectanea
Anatomae enim finis partis cognitio, propter quod, necessitas et usus. Philosophicis praecipue qui inde sciant ad umamquanque actionem quae requiruntur quod praestat. Medicis item qui inde constiutionem naturalem, regulam, quo diducendum aegrotantes, et inde quid agendum morbis.” ( Harvey 1616 Prelectiones anatomie universalis, f.4.)
So, the Rule of Socrates is Harvey’s way of talking about his use of comparative anatomy, and he thinks it necessary in order to understand the purpose and essence of the parts. This is perhaps the most innovative aspect of Harvey’s method, and it is one that, though we find it in other authors including Aristotle, is stressed more by Harvey than by almost anyone else—indeed, it is one of the primary ways Harvey takes other anatomists to task in his De motu cordis, claiming that their looking only at humans (and dead ones at that) is what led them astray in their understanding of the heart and the blood.
If we look at the other occurrence of the regula Socratis, we can connect this method of Harvey’s to Galen’s conception of the natural critieria and the importance of distinguishing similarity and difference:
[Called ‘caecum’] since its office is obscure. The size of a worm. In man, it is [counted] among the great [guts] for the sake of classification, as with the nipples. Conversely [in] hoggs, hare[s], oxen, ratt[s], etc., it is almost like another belly [in size]. In man it is sometimes large, as in the foetus WH, [as] Salomon Albertus [says], it is sometimes entirely absent. Thus the rule of Socrates through similarity in a great print.
Quia caecum officio. Magnitudo vermis. Homine inter magna tamen notae gratia ut paipillae. Contra hoggs, hare, oxen, ratt, etc., tanquam alter ventriculus. Homini aliquando magnum, ut foetu WH, Sal. Albert, aliquando non omnino. Hinc Socratis regula per similitudinem in a great print (Harvey 1616-1627 f.20.)
What the rule of Socrates allows is to be able to compare across animals and to discover the purposes of things which would otherwise be obscure. The reference to ‘similarity in a great print’ is a reference to Plato’s Republic, where he argues we can look at the city to understand the soul, as it’s easier to observe and understand. In the same way, Harvey, following Galen, thinks that by looking across animals, by obeying the rule of Socrates, we can compare and contrast and thus distinguish the similarities and differences in things which would otherwise be obscure in the case of a single specific animal. We can often see things more easily in comparative perspective, because the same organ might be larger, or easier to dissect, that is, it might be set up ‘in a great print’ and hence it will be easier to read off the uses and actions and determine the essence of this thing
Why is this called the rule of Socrates? The answer, I think, lies in a passage from Aristotle. If we think about Socrates’ method, we realize that it involves interrogating others so as to be able to find the truth of available opinions. This is what Harvey suggests: It is a method of interrogating one’s own opinions about the parts by, not only as Socrates does, by investigating other people’s opinions, but also by looking directly at the parts of different animals. And, as Aristotle wrote in the Metaphysics:
δύο γάρ ἐστιν ἅ τις ἂν ἀποδοίη Σωκράτει δικαίως, τούς τ᾽ ἐπακτικοὺς λόγους καὶ τὸ ὁρίζεσθαι καθόλου: ταῦτα γάρ ἐστιν ἄμφω περὶ ἀρχὴν ἐπιστήμης ( via Perseus )
Definition and induction are just those things we have been discussing: using many experiences (induction) to determine the essences of the parts (definition).