Aristotle on substance
In the Physics, Aristotle famously distinguishes between natural and artificial objects. Some examples of natural objects would be stones, copper, trees, and dogs. Some examples of artificial objects would be tables, paintings, automobiles, and computers. Or to take an example I like to use, a liana vine (the kind Tarzan swings around the jungle on) would be a natural object, and a hammock Tarzan makes out of living liana vines so as to nap in the afternoon would be an artifact.
There are different ways to explain the distinction. Aristotle characterizes natural objects as those whose principle of change and stability is internal to them, whereas artificial objects have their principle of change or stability imposed from outside. For instance, a liana vine’s tendencies to sink roots into the ground, draw water in through them, and grow upward toward the forest canopy all arise from within it. But the hammock made from living liana vines will maintain the proper shape, remain tied together, etc. only if Tarzan continuously maintains it by retying vines that have come apart, pruning them, and so on.
Another way to make the distinction is to note that natural objects have substantial forms, whereas artifacts have merely accidental forms. The mark of a thing’s having a substantial form is the presence of properties and causal powers that are irreducible to the sum of the properties and powers of its parts. Something having a merely accidental form, by contrast, has properties and causal powers that are reducible. For example, the distinctive properties and powers of a liana vine cannot be analyzed as merely a sum of the properties and powers of its parts (such as the cells, molecules, or atoms of which it is composed). But the properties and powers of a hammock can be reduced to the properties and powers of the vines it is made out of, together with Tarzan’s intention of using the vines to function as a hammock.
A third way to make the distinction is to note that natural objects have intrinsic or built-in teleology, whereas artifacts have merely extrinsic or externally imposed teleology. The tendencies of liana vines to sink roots into the ground and to grow upward toward the forest canopy are intrinsic to them, whereas their tendency to function as a hammock is externally imposed by Tarzan.
These three ways of making the distinction are closely related. A natural object’s intrinsic teleological features follow from its substantial form, and are manifested in the operation of its distinctive causal powers. For instance, the substantial form distinctive of a liana vine manifests itself in the vine’s being directed or aimed toward the ends of sinking roots into the ground, growing upward toward the forest canopy, etc. And the change and stability distinctive of such a vine is manifest in the operation of the causal powers by which the vine realizes these ends.
Similarly, the externally imposed end of functioning as a hammock determines which accidental forms Tarzan has to put into the vines (tying them this way rather than that, pruning them of these bits but not those) so that it will exhibit causal powers facilitating that end (e.g. the power to support the weight of an adult human being).
A true physical substance, for the Aristotelian, is an object that has a substantial rather than merely accidental form; which, accordingly, exhibits certain intrinsic rather than merely externally imposed teleological features; and which thereby manifests certain inherent patterns of change and stability. Artifacts are not true substances, precisely because they have merely accidental forms, externally imposed teleology, and patterns of change and stability that are not entirely inherent to them. Hence a liana vine is a true substance and a hammock is not. (I say more about the distinction between the natural and the artificial in my recent essay “Natural and Supernatural,” in the Simpson , Koons, and Orr volume Neo-Aristotelian Metaphysics and the Theology of Nature.)
Being an artifact is not the only way to fail to be a true substance, though. This is where aggregates come in. Suppose Tarzan ties a hammock between two trees, but later abandons and forgets about it. Imagine the vines that make it up die, and the whole thing comes loose and drops to the ground, forming a pile beneath the trees. Imagine that the vines come completely untied, dry out and fade, and take on the appearance of an amorphous mass or random tangle. Since the vines are dead and no longer exhibit the distinctive properties and powers of liana vines, they are on the Aristotelian view not strictly liana vines any longer at all. They are substances of some other kind instead – bits of fiber, say. And since the pile no longer has the distinctive features of a hammock (and Tarzan no longer even intends to use it as such) it is no longer a hammock either.
What is it? It is an aggregate of these new fibrous substances – a collection whose powers and properties are reducible to the sum of the parts of the collection. It is like an artifact, except that an artifact has a teleology imposed from outside by some mind, whereas an aggregate does not. This is so even if it behaves as if it did. For example, imagine that the pile of dead vines prevents water from flowing between the trees the hammock had fallen from. It functions as if it were a dam, but it is not strictly a dam since it was not built for that purpose (either by human beings or beavers, say).
Searle on intentionality
Let’s turn now to Searle’s distinction. Intentionality is a technical term for the directedness or “aboutness” characteristic of mental states and of linguistic and other sorts of representations. For example, your thought that the Eiffel Tower is in Paris is about or directed towards a certain object – the Eiffel Tower. The English sentence “The Eiffel Tower is in Paris” is also about or directed toward the Eiffel Tower, as is a painting of the Eiffel Tower. By contrast, a random string of letters like “gjaargrvma,” or the splotches on the ground that form when you accidentally spill some ink, have no intentionality. They are not about anything, but are mere meaningless marks.
Now, as Searle points out in several places (such as his book The Rediscovery of the Mind), these examples illustrate two different kinds of intentionality. The string of letters that make up the sentence “The Eiffel Tower is in Paris” has intentionality, whereas the random string “gjaargrvma” does not. But notice that the intentionality of the first string is not inherent to it. Intrinsically or all on their own, the first set of letters is as meaningless as the second. It’s just that, given the conventions of English usage, the first conveys a sentence and the second does not. Absent those conventions, the first would be as devoid of intentionality as the second or as an accidental splotch of ink.
Sentences thus have what Searle calls derived intentionality. So too does a drawing of the Eiffel Tower, and representations of other kinds such as symbols (for example, the symbols making up a “No smoking” sign). Now, the source of this derived intentionality is the human mind. The sentence “The Eiffel Tower is in Paris” has the meaning it does because it is used to express the thought that the Eiffel Tower is in Paris. Thoughts, however, do not in turn derive their meaning from anything else. We use sentences to convey the contents of thoughts, but nobody uses thoughts to convey the contents of thoughts or of anything else. Thoughts just are their contents, as it were. They have their meaning in a built-in way. They have intrinsic (or original) rather than derived intentionality.
(The way Scholastic writers like John Poinsot put this is to say that sentences are instrumental signs whereas thoughts are formal signs. An instrumental sign is a sign that is also something else – a set of ink marks, a noise, an image, or what have you. Its content is something additional to or distinct from these other features, and that is why for such features to have any content at all requires that the content be derived. A formal sign is a sign that is nothing more than a sign, and in particular nothing more than its content. It just is its content, which is why its content is intrinsic rather than derived.)
Searle also notes that there are phenomena that do not have intentionality of an intrinsic or even a derived kind, but which it is nevertheless useful to describe as if they had it. For example, when seeing dark clouds we might say “Those clouds mean that it will rain.” Naturally, the clouds don’t have such a meaning in the way that the thought that it will rain has meaning. For the clouds aren’t thinking. But neither do the clouds have meaning in the way that the sentence “It will rain” does or in the way that a drawing of rain does. A cloud is not a sentence, or a picture, or a symbol, or a representation of any other kind. Rather, what is going on is that, since we know there is a causal correlation between dark clouds and rain, we infer from the presence of the clouds that there will be rain. The meaning (in the sense of the conceptual or semantic content) is in us, not in the clouds. But describing the clouds as if they had semantic content is a useful shorthand. Searle calls this as-if intentionality, but emphasizes that precisely because it is only as if the phenomenon had intentionality, it is not strictly a kind of intentionality but a convenient fiction. Another example would be when we say that the water wants to get to the bottom of the hill (as if water really wanted anything).
Naturally, intrinsic intentionality is the most basic of the three. Derived intentionality exists only because there is intrinsic intentionality to derive it from. And as-if intentionality is a matter of speaking of a thing as if it had the intrinsic intentionality that thoughts have or the derived intentionality that words and the like get from the intrinsic intentionality of thoughts.
Now, there is a parallel between natural substances, artifacts, and aggregates on the one hand and intrinsic intentionality, derived intentionality, and as-if intentionality on the other. Consider first that natural substances are more fundamental than artifacts and aggregates, because the latter presuppose the former. In particular, an artifact is essentially a natural substance or collection of natural substances that have been arranged by someone to realize some end of his (such as Tarzan’s hammock). And an aggregate is a collection of natural substances that might superficially appear as if it were a natural substance or an artifact but is not, since it lacks the purposes of either (as in the case of the pile of dead vines).
Analogously, intrinsic intentionality is more fundamental than either derived or as-if intentionality. Like an artifact, something with derived intentionality (such as words, images, or symbols) reflects the purposes of some agent. Like an aggregate, something with as-if intentionality can seem like it reflects such purposes but does not.
The reason for the parallel has primarily to do with the different kinds of teleological features exhibited by the different kinds of physical objects. Teleology essentially involves directedness toward an end or goal. But intentionality also involves a kind of directedness, namely directedness toward an object of representation (whether representation in thought, in words, or whatever). The key difference is that intentionality involves directedness of a mental kind, whereas teleology need not (though it can). For example, the directedness of a liana vine to the ends of sinking roots into the ground, growing toward the forest canopy, and so on is in no way conscious or otherwise mental. For a liana vine has no mental properties of any kind.
If we think of directedness as the generic feature that both physical objects and intentionality can possess in different ways, then what the members of the two sets of distinctions have in common is this: natural substances and intrinsic intentionality both involve an inherent or built-in directedness; artifacts and derived intentionality both involve a borrowed or derivative directedness; and aggregates and as-if intentionality both involve no genuine directedness at all, but at most only the appearance of it.
These parallels also manifest themselves in the way Aristotelians and Searle would object to the notion that the human mind is literally a kind of computer. The Aristotelian would say that rational animals are substances of a kind, whereas computers are a kind of artifact. The former have substantial forms, intrinsic teleology, and irreducible causal powers; whereas the latter have merely accidental forms, derivative teleology, and reducible causal powers. So, it is just a category mistake to think of the mind as a kind of computer. Similarly, Searle has argued that minds have intrinsic intentionality, whereas computers have only a kind of derived intentionality. (Actually, the relationship between Aristotelianism and Searle vis-à-vis computers is somewhat more complicated than this. I have discussed it in detail in my Nova et Vetera article “From Aristotle to John Searle and Back Again: Formal Causes, Teleology, and Computation in Nature.”)
An awareness of the parallel I’m calling attention to is at least implicit in some comments Daniel Dennett makes in his essay “Evolution, Error, and Intentionality” (from his collection The Intentional Stance). Following W. V. Quine and others, Dennett holds that the meaning or semantic content of thoughts and utterances is indeterminate from the physical facts about human beings and their larger environment. That is to say, if the physical facts are all the facts there are, then there simply is no objective fact of the matter about what any of our utterances mean or about the content of any of our thoughts. (Recall Quine’s famous “gavagai” example.) Since these thinkers hold that the physical facts are indeed all the facts there are, they conclude that there is indeed no fact of the matter about what we mean when we say or think something.
Now, I have argued (in my American Catholic Philosophical Quarterly article “Kripke, Ross, and the Immaterial Aspects of Thought” and elsewhere) that while the premise about the semantic indeterminacy of the physical is true, the conclusion Quine, Dennett, and others draw from it is false, and indeed incoherent. The right conclusion to draw, I submit, is that thought is not physical. But for present purposes we can put that aside. What I want to call attention to here is that Dennett notes (at p. 321 of his essay) that (given his naturalistic assumptions) there can be no objective fact of the matter about natural functions any more than there can be about the meaning or semantic content of thought. That is to say, the same considerations that entail the indeterminacy of semantic content also entail indeterminacy about the teleological properties of natural objects. Just as, for Quine, there is no objective fact of the matter about whether “gavagai” means “rabbit” or “undetached rabbit part,” so too there is no fact of the matter about whether the function of the heart is to pump blood.
Now this position too, as I argue in chapter 6 of Aristotle’s Revenge, is ultimately incoherent. Teleological notions simply cannot be eliminated from biology, and if that result is incompatible with naturalism, then that is just another reason to reject naturalism. But even if you disagree with me about that, the point for present purposes is that Dennett’s position reinforces the idea that there is a parallel between the Aristotelian’s teleological notion of a natural substance and Searle’s notion of intrinsic intentionality. For it is precisely because of this parallel that Dennett (who is no fan of either Aristotelianism or Searle) wants to reject both of them together.