Porphyry and the Ontology of Genus and Species

Written by on August 27th, 2013. Subject: Philosophy. Filed in Logic, about Predicables Porphyry Aristotle

|||Porphyry, and Paul Vincent Spade. Five Texts on the Mediaeval Problem of Universals: Porphyry, Boethius, Abelard, Duns Scotus, Ockham. Indianapolis: Hackett Publishing, 1994.|||

Porphyry and Averroes They differ in that the genus contains the species, while the species are contained by and do not contain the genera. For the genus covers more than the species does. Again, genera must be posited in advance and, when informed by specific differences, complete the species. Hence genera are prior by nature. Also, they destroy the species along with themselves, but are not destroyed along with the species. If there is a species there is certainly the genus, but if there is a genus it by no means follows that there is the species. p 13.

|||Aristotle, and J. L. Ackrill. Aristotle’s Categories and De Interpretatione. New York: Oxford University Press, 2002.|||

Categories and On Interpretation Of the Substances the species is more a substance than the genus, since it is nearer to the primary substance. For if one is to say of a primary substance what it is, it will be more informative and apt to give the species than the genus. For example, it would be more informative to say of the individual man that he is a man than that he is an animal (since the one is more distinctive of the individual man while the other is more general); and more informative to say of the individual tree that it is a tree than that it is a plant. Further, it is because the primary substances are subjects for all the other things, so the species stands to the genus: the species is a subject for the genus (for the genera are predicated of the species but the species are not predicated reciprocally of the genera). Hence for this reason too the species is more a substance than the genus. p. 7.

In these two quotes we find two different approaches to the relationship between genus and species. In the Isagoge, Porphyry is considering the priority of intelligibility among the different predicables (genus, species, difference, property, and accident). Aristotle explicitly states that the individual is ontologically prior to the species. Porphyry is not explicit in the Isagoge, and in fact says that he wants to leave the question as to the reality of genus and species open.1 Can we construct an answer anyway without corrupting the text? Let us examine each of the statements about the priority of one predicable over another in an attempt to see if Porphyry would say whether the individual or the genus is prior to the species ontologically.

Now we need to examine the five different priorities that Porphyry outlines in an attempt to determine what type of priority he is talking about. We begin with the one quoted originally, the fact that genus is prior to species. Because a genus contains more than one species, the former would not be destroyed if the latter were destroyed. If the species man were destroyed, the genus animal would still exist. This works as we move up the tree to the ten categories, which are the ultimate genera2. In like manner, Porphyry outlines the other priorities between the different predicables (and for continuity we will again include genus versus species):

  1. genus is prior to difference3
  2. genus is prior to species (above)
  3. difference is prior to species4
  4. species is prior to property5
  5. species is prior to accident6

The arguments for 1-3 follow the same pattern: that which is prior is not destroyed by that which follows. The arguments for species being prior to both property and accident, however, sound like ontological ones. Porphyry has changed his approach when dealing with the relationships among these three predicables. It remains to be seen whether priorities 1-3 deal only with intelligibility (logical priority) or if they are also ontological. To solve this problem, we must first see why his approach has changed for 4 and 5.

If Porphyry were to use the same pattern in 4 and 5 as he did in 1-3, then he would be in trouble. Argument 4 would run thus, “Since species is not destroyed when the property is destroyed, species is prior to property.” Property in the strict sense, however, is defined as, “that in which belonging (i) to only one species, (ii) to all of it, and (iii) always, all go together, as risibility does to man.”7 Whereas the predicables in 1-3 have different levels of extension (the prior having more), a species and property have exactly the same extension. A property applies to every member of (and only to) that species. It does not help, then, to try to determine the priority in the same manner as in 1-3.

One side note is required. When Porphyry says that a property only applies to one species, he uses the connection between risibility and man. In this example, man is a species only, a most specific species (infima species), and cannot be a genus. Must we take his assertion about a property only being predicated of a species to mean that a property can only be predicated of an infima species? The broad definition says, “Species is what is arranged under the genus and is what the genus is predicated of with respect to what the thing is.”8 Species can be considered a unified concept under a genus anywhere in the middle of the tree. For example, animal can be considered a species of the genus “body.” As a species, “animal” denotes those things which have animate, sensate bodies and distinguishes them from the other species under “body.” Considered as a species, “animal” is a unified whole. As we have seen, “animal” can also be considered from the perspective of a genus. “Animal” can be divided by various differences to make species under it. The perspective from which one looks at the concept “animal” will determine whether it is being considered as a genus or species. Let us return to the definition of property as only being predicated of a species. Is it possible to take the use of “species” in the more flexible sense and not just as the infima species? If “animal” is considered as a species, is it possible to denote properties that are limited to it that do not apply to any other species under “living body”? It seems that there would be certain properties of animals that would not be directly part of the form “animal” but would nonetheless be predicated of animals alone (as species under the genus “living body”). It seems, then, that we can take “species” in the broader sense.

When Porphyry says, “Accident is predicated of species and of individuals,”9 species can be taken in the broad sense here as well. Unlike a property, however, accidents can be predicated of many species, no matter where you are in the tree. This makes it difficult to compare the extension of an accident and a species. Again, if we followed the pattern of 1-3, accident would seem to be prior to species because the former would still exist even if a particular species were destroyed. However, an accident must exist in a substrate.10 The ontological priority of the substrate is just as important in 5 as it is in 4. It is also important to recognize that while genus, species, difference, and property are closely united with what the thing is, accidents are not. In this way, accident is a unique predicable among the five listed.

After Porphyry defines the five predicables, he says that they are all predicated of several things and gives examples of the use of each.11 We only find the Aristotelian language (“primarily of the individuals”) when he lists separable accidents (i.e. being moved). We saw earlier that the species is prior to the accident. We see now that in this case the individual is prior to the accident. It has not been shown, thought, that species is prior to the individual or vice versa.

We find that in the Isagoge Porphyry refers mostly to species as the subject of a predication and sometimes uses both species and the individual as the interchangeable subjects of the other predicables. We need to look more closely at the move from individual to species in order to discover his intentions for 1-3. Is species prior to the individual both logically and ontologically? If both, then the genus is also prior in both respects. If it is only logically prior, then the individual will be ontologically prior (and thus would agree with the quote from Aristotle).

Recall that Porphyry does not want to say whether or not the genera and species are real things or not. With that in mind, let us return to the sequence of the predicables. Genus is prior to all the others, since it is prior to both difference and species, the latter of which is also prior to properties or accidents. We have seen that 4 and 5 have ontological considerations, but we have yet to see whether 1-3 do as well. It is important to note that the move from a genus to a species occurs in a manner other than the move from a species to an individual.12 To put it another way, to move from animal to man we add some intelligibility, the difference rational. When we move from man to Plato, or man to Socrates, no intelligibility is added.13 A species is the most specific set of intelligible principles of a substance. On the other hand, substance is more inclusive than animal. Using what we have discussed so far, let us examine what Porphyry says about the relationship between a species and the individual, “The most specific species also has one relation only, (a) the one to things prior to itself, of which it is a species. But it does not have the other relation, (b) to things after it, even though it is called a species of individuals. Rather it is called a species of individuals because it includes them, and again it is called a species of what are prior to it because it is included by them.”14 The species man has a relation to the genera above it (i.e. animal, body, substance), which are prior, but not to the individuals. There is a disjunction between the species, which includes the individuals, and the individuals. There is a relation, however, to the immediate genus, the genus of that genus, etc. The connection between genus and species is different than the one between the species and the individual.

We have discussed two possibilities for the priority of one term over another, that which was used for 1-3 and that which was used for 4 and 5. Is the move from species to individual more similar to the move from genus to species or from species to property or accident? The latter required an ontological argument, whereas the former seemed to involve a weaker, non-ontological one. Since Porphyry follows Aristotle when he states that being is not a genus, 1-3 must be a logical distinction. In that case, genus is logically prior to species. In that case, species is logically prior to the individual. That is to say, in the realm of intelligibility, the species remains even if no individual from that species still exists. However, the individual must exist before the species in the order of being. In the same way, species is closer to that which exists than the genus is. I believe if directly asked, Porphyry would agree with Aristotle that the individual is prior ontologically to the species.

About Brandon Bridger

Brandon Bridger graduated from the College of St. Thomas More. He is currently doing graduate course work in philosophy at the Catholic University of America.

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  1. “I shall abstain from deeper enquiries and aim, as appropriate, at the simpler ones. For example, I shall beg off saying anything about whether genera and species are real or are situated in bare thoughts alone.” Ibid., p. 1 

  2. “For being, as Aristotle says, [Metaphysics III. 3, 998b22], is not one common genus of all things; neither are all things ‘homogeneous’ in accordance with one highest genus. Instead let us posit the ten first genera as ten first principles, as in the Categories.” Isagoge p. 5 

  3. “Genera are prior to the differences under them, because the former destroy the latter along with themselves, but are not destroyed along with the latter. For if animal is destroyed, rational and irrational are destroyed along with it. But differences never destroy the genus along with themselves. For even if all its differences were destroyed, animate sensate substance is still conceived, and that was the genus.” Ibid., p 12 

  4. “Again, difference is prior to the species made in accordance with it. For when rational is destroyed it destroys man along with it. But when man is destroyed it does not destroy rational, since there is still god.” Ibid., p. 16 

  5. “Species has its reality prior to property, while property follows after species. For man must exist in order to be risible.” Ibid., p. 17 

  6. “Species are conceived before accidents are, even if they are inseparable ones. (For the substrate has to exist in order for anything to be accidental to it.) But accidents naturally arise later and have an adventitious nature. 

  7. Ibid., p. 10 

  8. Ibid., p. 4 

  9. Ibid., p. 11 

  10. “Accident is what comes and goes without the destruction of the substrate.” Ibid. 

  11. “For animal is predicated of horses and oxen, which are species, and of this horse and this ox, which are individuals. Irrational is predicated of horses and oxen, and of particulars. A species, such as man, is predicated of particulars only. A property, such as risibility, is predicated both of man and of particular men. Black, which is an inseparable accident, is predicated of the species of crows and of the particulars, whereas being moved, which is a separable accident, is predicated of man and of horse - primarily of the individuals, and in a secondary sense of the species that include the individuals.” Ibid., p. 11 

  12. “The individual then is included under the species and the species under the genus. For the genus is a kind of whole and the individual a part, while the species is both a whole and a part, although a part of one thing and the whole not of another thing but rather in other things. For the whole is in the parts.” Ibid., p. 7 

  13. “Therefore, the most general genera are ten. The most specific species are of a certain number too, surely not infinite. That is why Plato exhorts us [Philebus, 16c-18d, Politicus, 262a-c] to stop after going down from the most general to the most specific, to go down through the intermediary levels and to divide by differences. He tells us to leave the infinite [individuals] alone. For there is no knowledge of them.” Ibid., p. 5-6 (The next time someone says, “I know you,” reply, “No you don’t. Plato says so.”) 

  14. Ibid., p. 5