Monthly Archives: December 2015

Aristotle: Is “Non-feathered” a Genus of Animals?

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In the last post I primarily addressed Aristotle’s objection to dichotomous division, a taxonomic method that Platonists used to determine the kinds of animals there are and where any particular animal kind fits, an enterprise roughly equivalent to the animal-classification that for contemporary biology results in the designation of genus and species.  In particular, amongst Aristotle’s objections to dichotomous division, he says that grouping birds into, say, feathered and non-feathered, results in the absurdity that the latter does not exist

And yet it is necessary to divide by privation, and the dichotomists do divide [in this way].  But there is no difference of a privation qua privation.  For it is impossible for there to be species of what is not, for example of “non-footed” or of “non-winged” just as there are species of “footed” and “winged.”  Furthermore it is necessary that species belong to a generic difference.  For if they do not, why would they belong to a generic difference and not a specific difference? (Aristotle, Parts of Animals, 642b21-26).(1)

The objection substantively amounts to this: because a privation does not exist, e.g. “non-winged,” there cannot be any species subsequently derived from it.  And, as the concluding question makes clear, if in fact no pair of species can be divided from it, then this means that, e.g. “non-winged,” is a species.  This is evidently false, however, because “non-winged” is as indeterminate a species for ancient taxonomy as it would be for modern biology.

However, what if Platonists appealed to Aristotelian privation in making a case for dividing privation?   In his Physics Aristotle says this:

But white comes to be from the non-white, and not from everything [that happens to be non-white] but from black or from something between black and white, and an educated man comes to be from something that is not educated, but not just from anything that is not educated, but rather from an uneducated man, unless this happens incidentally.  Again the white turns into the non-white, and not into the chance non-white but into the black or an intermediate (Physics 188a36-188b6). (2)

Now Aristotle is clearly, in context, discussing how things come to be, and more particularly how this generation comes about from opposites.  A black beard, for example, comes to be white, where this whiteness is explicable by saying it comes to be from “non-white,” yet not just any non-white (as say, the number 1 is non-white), but from the opposite of white, black, or an intermediate, gray.

Nevertheless it seems plausible that this concept of privation, although employed to a very different purpose in the Physics than in our taxonomic concerns, establishes that we can use privation as a faithful ontological characterization of things.  If that is the case, there is no reason we cannot use “non-feathered” as a genus from which we can further dilineate more species.

Would Aristotle accept this understanding of privation from Physics for his work on animal classification?

More broadly, does this eliminate Aristotle’s original objection to privation as a method of division?

(1)
Translation mine:
Ἔτι στερήσει μὲν ἀναγκαῖον διαιρεῖν, καὶ διαιροῦσιν οἱ
διχοτομοῦντες. Οὐκ ἔστι δὲ διαφορὰ στερήσεως ᾗ στέρησις·
ἀδύνατον γὰρ εἴδη εἶναι τοῦ μὴ ὄντος, οἷον τῆς ἀποδίας ἢ τοῦ
ἀπτέρου ὥσπερ πτερώσεως καὶ ποδῶν. Δεῖ δὲ τῆς καθόλου δια-
φορᾶς εἴδη εἶναι· εἰ γὰρ μὴ ἔσται, διὰ τί ἂν εἴη τῶν καθόλου
καὶ οὐ τῶν καθ’ ἕκαστον;

(2)
Translation mine:
ἀλλὰ λευκὸν μὲν γίγνεται ἐξ οὐ λευκοῦ, καὶ τούτου οὐκ ἐκ παντὸς
ἀλλ’ ἐκ μέλανος ἢ τῶν μεταξύ, καὶ μουσικὸν οὐκ ἐκ μου-
σικοῦ, πλὴν οὐκ ἐκ παντὸς ἀλλ’ ἐξ ἀμούσου ἢ εἴ τι αὐτῶν
ἐστι μεταξύ. οὐδὲ δὴ φθείρεται εἰς τὸ τυχὸν πρῶτον, οἷον
τὸ λευκὸν οὐκ εἰς τὸ μουσικόν, πλὴν εἰ μή ποτε κατὰ συμ-
βεβηκός, ἀλλ’ εἰς τὸ μὴ λευκόν, καὶ οὐκ εἰς τὸ τυχὸν ἀλλ’
εἰς τὸ μέλαν ἢ τὸ μεταξύ·

Aristotelian Objections to Platonic Animal Classification

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Deep into his criticism of the dichotomist method of division, Aristotle and his opponents are deciding what genera and species of animals truly exist.  To discover these natural kinds of animals, the appropriate method of division, that is, a way of separating animals from each other into categories precisely representative of species, is under contentious dispute.

And yet it is necessary to divide by privation, and the dichotomists do divide [in this way].  But there is no difference of a privation qua privation.  For it is impossible for there to be species of what is not, for example of “non-footed” or of “non-winged” just as there are species of “footed” and “winged.”  Furthermore it is necessary that species belong to a generic difference.  For if they do not, why would they belong to a generic difference and not a specific difference? (Aristotle, Parts of Animals, 642b21-26).(1)

Some say that species should be divided into two with each of the two branches always branching off into two more, until the point where a termination results in an actual species.  For example, if we begin by dividing animals into footed and non-footed, and then the footed into bi-pedal and poly-pedal, we can then divide bi-pedal into split-toed and web-toed, etc.  Advocates of this process of dichotomy are called dichotomists.

Aristotle, on the other hand, advocates opening more than one line of division, not limiting himself to the dichotomist method which follows only one of two branches at every step.  In this section of the text, Aristotle, believing that dichotomists commit themselves to “privation” as well, argues that privation is incompatible with dichotomy.  By privation Aristotle simply means a negation of some difference, such as in the example above, “non-footed” as contrasted with “footed.”  The privation objection demonstrates Aristotle’s characteristic subtlety and insight as he, perhaps ironically, forces his opponents into a logical dichotomy: Either the privation is an actual species of animal or it is not, and further division must continue.

Now if we continue with the first option, that there is an actual species of privative animal, say, non-footed, then this seems precluded for the following reasons.  Most obviously, something which is not cannot be said to be.(2) It is also the case that being non-footed would not pick out a species, as it could generically apply to a worm, a whale and a snake, not to mention the variations of each animal.  And yet, even if it were that case that “non-footed” faithfully picked out only a single animal (pretend that earthworms are the only non-footed animals), it is unclear how non-footed is an essential property of earthworms.  After all, earthworms are also furless, wingless, knuckle-less, eyelash-less, and money-less, to name just a few things.

On the other hand, if the privation is not a species, but must be further divided, then Aristotle clearly precludes this possibility in the above text.  Why this is so is unclear, but I will have a preliminary answer in the next post, as well as offer up a Platonic solution which could perhaps stand up under Aristotle’s scrutiny.

 

REFERENCES:

 

(1)
Translation mine:
Ἔτι στερήσει μὲν ἀναγκαῖον διαιρεῖν, καὶ διαιροῦσιν οἱ
διχοτομοῦντες. Οὐκ ἔστι δὲ διαφορὰ στερήσεως ᾗ στέρησις·
ἀδύνατον γὰρ εἴδη εἶναι τοῦ μὴ ὄντος, οἷον τῆς ἀποδίας ἢ τοῦ
ἀπτέρου ὥσπερ πτερώσεως καὶ ποδῶν. Δεῖ δὲ τῆς καθόλου δια-
φορᾶς εἴδη εἶναι· εἰ γὰρ μὴ ἔσται, διὰ τί ἂν εἴη τῶν καθόλου
καὶ οὐ τῶν καθ’ ἕκαστον;

(2)
I assume A. would approve this, for he says something logically analogous in the case where we suppose that privations are divided into further species.

Against Empiricism: Galen’s Arguments

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Galen’s Rationalism, properly understood and practiced, involves an appropriation of experience, in that by taking hold of and building upon phenomena the doctor-philosopher achieves a superior type of knowledge, an art of medicine.  Insofar as this is the case then, Rationalism is inarguably a more robust theory of knowledge compared to Empiricism, which in fact is subsumed into this Galenic Rationalism.  On the other hand, however, if Empirical phenomena are not incorporated into the superior methods of Rationalist understanding, then to this same degree they are deficient and wanting.  This naked kind of Empiricism is exactly the target of Galen’s criticism, of which I present two arguments below.

The first of these criticisms can be subtle on a first reading, and deals with argument itself.  Galen says,

For it is not their view [the Empiricists] that one can judge the truth of the matters in question in these accounts, since they believe that evident perception and memory suffice for the constitution of all arts.  But, to judge such matters it is necessary to suppose that there is some power in us which is able to consider and to judge what is incompatible and what follows.  If, then, there is no such power in us, we should not endeavor either to produce arguments ourselves or to refute those arguments which have been argued badly (Outline of Empiricism 44 trans. Walzer, Frede).(1)

Galen is not here saying that Empiricists recuse themselves from the dispute about the role of reason in medicine; rather he is forcing the point that the Empiricists have no standing when it comes to arbitrating any dispute because they have nothing to arbitrate by, except inert experience.  In order to appeal to the superiority of Empiricism over Rationalism, one has to make use of reason itself, but this would appeal to something beyond experience and memory, a resource which Empiricism does not have.  In fact, Galen implies that Empiricists are unable to be consistent in their adherence to Empiricism, since even it requires “some power in us which is able to consider and to judge what is incompatible and what follows.”  Thus, even on a strictly Empiricist program, there must be judgments about what is similar or dissimilar, compatible or incompatible, consistent or inconsistent concerning the phenomena under investigation, if one is expected to categorize or understand the information.  In summary, to argue at all is to enter into the Rationalist camp.(2)

There is an equally clever, perhaps sophistic, argument against Empiricism which was mentioned earlier in the treatise as well, but gets it full narrative force in On Medical Experience.  Galen is attempting to use a traditional sorites-type argument and apply it to medical practice.  The puzzle is summarized as follows: if it is agreed that the art of medicine is constituted only by a number of experiences, at precisely what number of experiences do we say that a doctor has acquired the art of medicine?  He pesters the Empiricist to respond as to why a certain number of experiences is not sufficient to guarantee this art: is it 12, 40, 100 times?  No matter the number, though, says Galen, it will be a finite number.  He can then ask why it is that one less than this critical number is not sufficient to constitute the art.  More importantly though, he has shown a point of inconsistency in the Empiricist’s method which cannot be solved by experience.  The inconsistency is that the Empiricist’s initial position was that one experience was insufficient for the acquisition of the art.  But now when say the critical number is 50, in the process of passing from 49 to 50 experiences, that is, the addition of one experience, then the Empiricist claims that this single experience makes all the difference.  I take it this sorites argument appeals to Galen’s earlier contention that Empiricism, in its very nature, is not equipped to deal with arguments, since these lay outside the realm of phenomena.  Yet it also seems that Galen is pointing out something about the very nature of experience.  Experience, as the Empiricist wishes to have it in the medical art, is deeply limited in Galen’s view, because, were it not for the addition of something else at a given point during the procedure of induction, induction would blithely continue on ad infinitum with, quite literally, no reason for it to pause in its course.  The impetus for experiences to coalesce into an art cannot come from experiences themselves, no matter how numerous, but from some guiding rational principle that orders and arranges the information into a comprehensible whole.  This rational principle, of course, if it is discerned by a faculty specially designated to identify this rationality, need only be exposed to the faculty a single time for it to be properly identified.  This efficacy, a singular identification from a single exposure, is Galen’s point, and he is here forcing the Empiricist to concede it, whether it be Galen’s explanation of a Rationalist faculty or under the conditions of Empiricist induction, as this sorites argument would have it.

 

Footnotes:

(1) This text is extant only in a Latin translation by Nicolaus of Reggio in 1341.  I unfortunately do not have access to this text.

(2) There is not only an appeal to rational argument, but further, to a faculty, perhaps analogous to that between experience and the senses.  Thus there is both reason and the faculty of reason, neither of which the Empiricist can appeal to.  This argument plays right into Galen’s second objection as well, as I show.

References:

Galen. “An Outline of Empiricism.” Three Treatises on the Nature of Science. Trans. Richard Walzer and Michael Frede. Indianapolis, IN: Hackett Pub., 1985.

Galen. “On Medical Experience.” Three Treatises on the Nature of Science. Trans. Richard Walzer and Michael Frede. Indianapolis, IN: Hackett Pub., 1985.