Causes in Plato’s Phaedo

As Socrates recounts his search for causes (aitiai) in the Phaedo, he identifies the following as genuine causes: intelligence (nous), seeming best, choice of the best, and the forms. I argue that these causes should be understood as norms prescribing the conditions their effects must meet if those effects are to be produced. Thus, my account both explains what Socrates’ causes are and the way in which they cause what they cause.


INTRODUCTION
In the Phaedo, Socrates relates how his search for the αἴτιαι (causes, explanations) of things-why they come to be, pass away, and are (96a5 ff.)-eventually led him to posit the forms. The sense in which the forms are αἴτιαι, however, is not as obvious to we contemporary readers as it was to Phaedo and Echecrates, who claim that Socrates' account was "wonderfully clear to anyone with even a little intelligence" (102a4-5). 1 Part of the difficulty is that the way Socrates uses the word "αἰτία" and its adjective cognate "αἴτιον" in the Phaedo renders them notoriously difficult to translate. I will translate "αἰτία" and "αἴτιον" indifferently as "cause," "explanation," or "reason why," with the recognition that none of these capture the Greek without considerable ambiguity. Yet, even ignoring the problem of translation, the difficulty of understanding the specific notion of αἰτία or cause Socrates uses remains. In responding to this difficulty, scholars typically adopt one of three basic approaches. One approach is to claim that Socrates' account of causality is, as Ian Crombie put it, "simply a nest of confusions" (Crombie, 1963, 2:169; see also Taylor, 1969;Hackforth, 1955, 131, 161;Burge, 1971, 8;Stough, 1976;Ruben, 2015, 51-52). On this approach, the main philosophical interest of the passage is to determine what made such confused notions of causality seem plausible to Plato. For those who find this unsatisfying, a second approach is to argue that Socrates' account is not fundamentally misguided, but simply lacks helpful distinctions between different kinds of causes that we find in later philosophers, such as Aristotle (e.g. Zeller, 1888, 263, n. 110;Shorey, 1933, 179;Vlastos, 1969;Burge, 1971;Fine, 1987;Byrne, 1989;Bolton, 1998;Dancy, 2004, 291-310;Ruben, 2015, 45-76). According to this approach, the confusion we experience in reading Socrates' account can be cleared up by identifying the sorts of causality with which he is concerned at various stages in his story as formal, final, efficient, logical, teleological, etc. A third approach is to prescind from these sorts of distinctions and instead attempt to uncover a more basic notion of causality that renders what Plato has Socrates claim in the Phaedo both intuitive and plausible (e.g. Eck, 1994;Sedley, 1998;Bailey, 2014). According to this approach, Socrates' account of causality is neither confused nor fails to make helpful distinctions.
This article takes the third approach. I will attempt to identify a single notion of causality that explains Socrates' initial attraction to Anaxagoras, his discussion of the causes of his sitting in prison, and the causality he attributes to the forms. The notion of causality Plato has Socrates employ in the Phaedo is remarkably strict. In order for Socrates to consider C a genuine cause of something's being E, (1) C must be such that it cannot be responsible for anything's being something contrary to E; and (2) anything that is contrary to C cannot be responsible for something's being E (cf. Burge, 1971, 4-5;Cresswell, 1971;Annas, 1982, 316;Matthews and Blackson, 1989, 584;Sedley, 1998, 121;Hankinson, 1998, 89-94;Kelsey, 2004, 23-24;Ebrey, 2014, 251-56). The sort of causal paradigm Socrates seems to have in mind is how the virtue courage, say, causes someone to act courageously. Courage cannot be the cause of someone's acting in a way contrary to acting courageously and anything that is contrary to courage, such as cowardice, cannot be the cause of someone's acting courageously (see 68d2-69a4). David Sedley and others have, I think, convincingly shown how the various sorts of things Socrates identifies as genuine causes in the Phaedo fit Socrates' causal paradigm (e.g. Sedley, 1998;Ebrey, 2014;Bailey, 2014). The question that, to my knowledge, has not been sufficiently addressed in the literature is the manner in which the causes Socrates identifies as genuine produce their effects. Yet until this question is addressed, Socrates' causal paradigm in the Phaedo will seem implausible to many contemporary readers. My goal in this article is to address this question and offer an account of Socrates' genuine causes that explains the way they produce their effects.
One may object that the manner in which causes produce their effects is not addressed in the Phaedo. After all, Socrates explicitly claims that he does not confidently affirm how and in what way (ὅπῃ δὴ καὶ ὅπως) the Beautiful makes things beautiful (100d5-7). Yet although Socrates does not directly address the question of the way his genuine causes produce their effects, as interpreters of the Phaedo trying to determine the plausibility of Socrates' account, we must address this question. Addressing this question, however, does not require that we decide whether it is through its presence (παρουσία), communion (κοινωνία), or whatever else that the Beautiful causes beautiful things to be beautiful (100d5-6). All that is needed is a generic account of the way in which the kind of causes Socrates considers genuine cause what they cause.
I will argue that the causes Socrates identifies as genuine in the Phaedo produce their effects by being norms. By a "norm," I mean a principle that prescribes the conditions things must meet in order to be governed by that principle. There are of course different kinds of norms. Ethical norms, for example, prescribe the conditions that given actions in given contexts must meet in order to be ethically right, that is, in order to be actions governed by ethical norms. Likewise, social norms-such as standards for dress, for what sorts of conversations are appropriate in a given context, and so on-prescribe the conditions that must be met if one's attire, speech, comportment, and so on are to be "socially acceptable," that is, governed by the relevant social norms. Similarly, the words "intelligence" and "reason" in English, like the word "νοῦς" in Ancient Greek, sometimes indicate a norm. For instance, when Ismene says to Antigone, "τὸ γὰρ περισσὰ πράσσειν οὐκ ἔχει νοῦν οὐδένα (to do the excessive is not intelligent)" (S. Ant. 67-68), she is not saying that Antigone does not possess a faculty of thought or even that Antigone lacks the mental quality of "good sense." Rather she is saying that the act of burying their brother in violation of Creon's command is not an "intelligent thing to do," and thus fails to meet the conditions prescribed by the norm that determines which action in a given situation is "the intelligent thing to do." Phrases like "the intelligent thing to do" point to a norm that we could simply call "reason," "intelligence," or "νοῦς." While the nature and metaphysical status of these various kinds of norms are matters of controversy, that they are norms of the sort I have indicated is clear. Each is a principle that prescribes conditions things must meet if those things are to be governed by that principle.
The examples I have given so far are all norms that concern action or behavior. Yet, as I hope to demonstrate, in addition to these sorts of norms, Socrates posits ontological norms in the Phaedo: the forms. I will argue that each form, F, is an ontological norm that prescribes the conditions a thing must meet in order to be an F kind of being. 2 In this way, to be an F kind of being is to be governed by the norm that is form F. The form Smallness, for example, is a norm prescribing the conditions a thing must meet in order to be small. It prescribes, for instance, that whatever is to be small must be exceeded by something else. Only insofar as a thing meets the conditions prescribed by Smallness can that thing be small.
As Socrates recounts his search for causes in Phaedo 96a5-102d4, the only things he identifies as genuine causes are intelligence (νοῦς) (97b8-99c8), seeming best (δόξα τοῦ βελτίστου) (99a2), 3 choice (αἵρεσις) of the best (99b1), and the forms (99d1 ff.). My contention is that each of these, insofar as it is a cause, is a norm. I will argue that Socrates characterizes (1) intelligence as a norm that prescribes the conditions things must meet in order to be arranged in the best way; (2) the seeming best of an action to person P as a norm that prescribes the conditions the potential doer of the action must meet in order to do what seems best to P; (3) a choice of the best as a norm that prescribes the conditions P's actions must meet in order both to be actions that seem best to P and actions that are in fact arranged in the best way; and (4) the forms as norms that prescribe the conditions things must meet if they are to be the kinds of beings that correspond to the forms in which they participate.

CAUSES AS NORMS IN THE "FIRST SAILING"
When recounting his "first sailing" in search of the causes of why things come to be, pass away, and are, Socrates identifies intelligence (νοῦς), seeming best (δόξα τοῦ βελτίστου), and choice (αἵρεσις) of the best as genuine causes, while rejecting the materialist accounts of causation he found in the teachings of those who engaged in what he calls "inquiry into nature" (96a7; περὶ φύσεως ἱστορίαν). 4 Socrates' argument that materialist causal accounts posit things without which genuine causes could not cause, rather than genuine causes themselves, proceeds in three stages. In the first (98b7-d8), Socrates (i) compares Anaxagoras' claim that Intelligence is the cause of all things to the claim that "Socrates does all the things he does because of intelligence" (98c4); and (ii) compares materialistic causal accounts of natural phenomena to an account according to which Socrates' bones, sinews, and other parts of his body are the cause of his doing the actions he does, for example sitting in prison. In the second stage (98e1-99a4), Socrates identifies four true causes of his sitting in prison, all of which are various instances of a seeming or appearance of the best. In the third and final stage of the argument (99a4-b4), Socrates returns to the general claim that intelligence is the cause of all his actions and concludes that Anaxagoras' materialist causal accounts are inadequate.
If intelligence, seeming best, and choice of the best are understood as norms, the following reading of Socrates' argument results. In stage one, Socrates compares Anaxagoras' claim that Intelligence is the cause of all things to the claim that all the actions Socrates does are done because of intelligence. If intelligence is understood as a norm prescribing the conditions things must meet in order to be arranged in the best way (see 97c5-6), then to claim that all the actions Socrates does are done because of intelligence is to claim that all the actions Socrates does meet the conditions prescribed by that norm. Thus, if intelligence is understood as a norm, the claim that all Socrates' actions are done because of intelligence entails that all Socrates' actions are in fact arranged in the best way, or rightly done, 5 just as Anaxagoras' claim that Intelligence is the cause of all things entails that all things are arranged in the best way.
In stage two of the argument, Socrates identifies four true causes of his sitting in prison and also what would have been the cause of his being in Megara or Boeotia, had he decided to escape at Crito's bidding. The following is the relevant text: Since (ἐπειδή) it seemed to the Athenians to be better (Ἀθηναίοις ἔδοξε βέλτιον εἶναι) to vote against me, therefore on account of these things (διὰ ταῦτα δή) it has also, in turn, seemed better to me (καὶ ἐμοὶ βέλτιον αὖ δέδοκται) to sit here, and more just, standing my ground, to undergo the penalty which they ordered. Since (ἐπεί), by the Dog, I suppose long ago these bones and sinews would have been in Megara or Boeotia, carried by a seeming best (ὑπὸ δόξης φερόμενα τοῦ βελτίστου), if I had not believed it to be more just and noble (εἰ μὴ δικαιότερον ᾤμην καὶ κάλλιον εἶναι), before fleeing and escaping, to undergo whatever penalty was ordained by the city. (98e1-99a4) While Socrates names four different causes of his sitting in prison, the causal conjunctions ἐπειδή at 98e1 and ἐπεί at 98e5, taken together with διὰ ταῦτα δή at 98e2-3, indicate that two of the causes stand in an explanatory relationship to the other two. Socrates claims that (1) since (ἐπεί) it seemed to him more just and noble to undergo whatever penalty was ordained by the city (98e5-99a4) and (2) since (ἐπειδή) it seemed better to the Athenians to vote against him (98e1-2), therefore on account of these things (διὰ ταῦτα δή), (3) it seemed to him more just to undergo the penalty the Athenians ordered (98e4-5) and (4) seemed to him better to sit in prison (98e3).
If one were to ask why Socrates is sitting in prison, the immediate answer would be because it seems better to him to do so than to do any of the alternative actions he could be doing (=4). Further, his sitting in prison is part of his act of standing his ground and undergoing the penalty the Athenians have ordered, an act that seems to him more just than any of the available alternatives (=3). If one were to ask why it seems more just to him to undergo the penalty the Athenians ordered, the answer would be because he believes it more just and noble to undergo whatever penalty is ordained by the city (=1) and it seemed better to the Athenians to vote against him (=2). In this way, the seeming more just of undergoing the penalty and the seeming better of sitting are the causes of Socrates' sitting and undergoing, whereas Socrates' belief that it is more just and noble to undergo whatever penalty the city ordains and the seeming better to the Athenians of voting against him are the causes of the seeming more just to him of undergoing and the seeming better of sitting. Accordingly, I will call (3) and (4) the "immediate causes" of Socrates' sitting and undergoing, and (1) and (2) "mediate causes." The immediate causes of Socrates' sitting can be understood as norms in the following way. The seeming more just to Socrates of undergoing the penalty and the seeming better of sitting in prison are norms prescribing the conditions Socrates must meet in order to do what seems better to him. Consider the seeming better of sitting in prison. This seeming better to Socrates prescribes various conditions he must meet if he is to sit in prison. Socrates himself expounds some of these conditions; for example, that his body must be "composed of bones and sinews" (98c6-7), that the bones must be "firm and have joints separate from one another" (98c7-8), that the sinews must be "such as to contract and relax" (98c8-d1), and that "when the bones are hanging in their joints, the relaxation and contraction of the sinews" must make his "limbs able to bend" (98d3-5). Yet these are not the only conditions or even the most noteworthy. The most significant condition prescribed by the seeming better to Socrates of sitting in prison is that Socrates' limbs must bend into a sitting position there in the prison and maintain themselves in that position. This condition is what separates the seeming better of sitting in prison from, say, the seeming better of escaping. Both the seeming better of sitting and the seeming better of escaping require a body composed of bones and sinews such that the limbs are able to bend, but only the seeming better of sitting in prison prescribes that Socrates' limbs bend and maintain themselves in a sitting position in the prison.
A consideration of some ways Socrates' actions could have failed to meet the conditions prescribed by the seeming better of sitting in prison can help further elucidate its normative character. First, imagine a scenario in which Socrates agreed to Crito's proposal, successfully escaped, and ended up in Megara. Imagine, however, that on the day on which he was supposed to drink the poison he regretted his decision to escape. In this scenario, escaping seemed better to Socrates while he was escaping, but then, upon further ref lection, after he is already in Megara, remaining and sitting in prison begins to seem as if it would have been the better course of action. In a case like this, however, the seeming better of sitting in prison on the day he was to drink the poison is not the cause of his sitting there. After all, he is not in prison and so is unable to sit there. One of the conditions prescribed by the seeming better of sitting in prison is being in prison. Consequently, being in prison is a condition without which the seeming better of sitting in prison cannot be a cause. The seeming better of sitting in prison in this scenario is a norm, but Socrates' bones and sinews, since they are in Megara instead of in prison in Athens, cannot conform to that norm. Thus, that norm is not the cause of any act of sitting in prison in this case.
Next, consider a scenario in which it seems better to Socrates to stand in his prison cell, but the jailer ties him down to the bench, forcing him into a sitting position. In this case, Socrates' bones and sinews would be in a sitting position. Thus, Socrates appears to meet the conditions prescribed by the seeming better of sitting, even though in this scenario sitting does not seem better to him. Further consideration reveals, however, that in this situation his sitting would not meet the conditions prescribed by the seeming better of sitting. If the ropes are forcing Socrates into a sitting position as he struggles to break free, then although his bones and sinews may be in a sitting position, the sinews are not meeting the conditions of relaxing and maintaining his limbs in a sitting position. Instead they are straining in resistance and struggling to break free of the ropes. Moreover, he is resisting and struggling precisely because resisting and struggling seems better to him than sitting. Hence, the seeming better of resisting and struggling is the norm to which Socrates' actions conform. If, by contrast, Socrates were to decide not to struggle to break free as he is tied down, but instead to sit as the jailer ties the ropes around him, then we are back to a scenario in which sitting seems better to Socrates.
These scenarios reveal how the seeming better of sitting in prison, understood as a norm to which Socrates conforms when he sits in prison, produces its effect and meets the criteria for genuine causes Socrates identifies. As discussed above, Socrates assumes that if C is a genuine cause of something's being E, then (1) C must be such that it cannot be responsible for anything's being something contrary to E; and (2) anything that is contrary to C cannot be responsible for something's being E. The seeming better to Socrates of sitting in prison, understood as a norm prescribing the conditions Socrates must meet in order to do what seems better to him, cannot be the cause of an action contrary to sitting in prison, since any action contrary to sitting in prison would not meet the conditions prescribed by the seeming better of sitting in prison. Likewise, the act of sitting in prison will not meet the conditions prescribed by any norm that is contrary to or incompatible with the seeming better of sitting in prison. Thus, understanding the seeming better of sitting as a norm allows it to meet Socrates' causal criteria. Furthermore, understanding the seeming better of sitting as a norm reveals how it causes what it causes. The seeming better to Socrates of sitting causes Socrates' sitting by simply being the norm to which Socrates must conform if he is to do what seems better to him.
The ot her immediate cause Socrates identifies is that it seems to him more just to undergo the penalty the Athenians ordered. This cause can be understood as a norm in the same way. The seeming more just of undergoing the penalty is a norm prescribing the conditions Socrates must meet in order to do what seems more just to him. Moreover, given that Socrates thinks it is never good to do injustice (see esp. Cri. 49a4 ff.), any action that seems more just to him also seems better to him. Hence, the seeming more just to Socrates of undergoing the penalty is also a norm prescribing the conditions he must meet in order to do what seems better to him.
Having considered the immediate causes of Socrates sitting in prison and undergoing the penalty, we can now turn to the mediate causes of those actions, namely, (1) that Socrates believes it more just and noble to undergo whatever penalty is imposed by the city and (2) that it seemed better to the Athenians to vote against Socrates. Socrates' belief that it is more just and noble to undergo whatever penalty the city ordains is a norm prescribing conditions Socrates must meet in order to do what seems more just and noble to him. Yet the conditions prescribed by that belief will be indeterminate until what is ordained by the city is specified. The seeming better to the Athenians of voting against Socrates provides this specification. The seeming better to the Athenians of voting against Socrates is a norm prescribing the conditions Socrates must meet in order to do what seems better to the Athenians, which is to say, in order to do what is ordained by the city. Hence, when operating together, mediate causes (1) and (2)-Socrates' belief that it is more just and noble to do whatever is ordained by the city and the seeming better to the Athenians of voting against him-provide the normative force of immediate causes (3) and (4)-the seeming more just of undergoing the penalty commanded by the Athenians and the seeming better of sitting in prison. None of the true causes of Socrates' sitting in prison operate independently. Instead, they operate within a normative causal network in which various beliefs and seemings are norms and causes.
After describing the causes of his sitting in prison, in stage three of the argument Socrates explicitly contrasts genuine causes of actions with things without which the actions caused would be impossible: But if someone said that without having such things-bones, sinews, and whatever else I have-I would not be able to do the things that seem best to me (τὰ δόξαντά μοι), he would be telling the truth. However, saying that it is because of them that I do what I do, and that I do these things because of intelligence (καὶ ταῦτα νῷ πράττων), but not because of a choice of the best (ἀλλ᾽ οὐ τῇ τοῦ βελτίστου αἱρέσει)-that would be a profoundly careless way of speaking. For it is unable to distinguish that what is the real cause is one thing while that without which the cause could never be a cause is another thing. (99a5-b4) In this passage, Socrates differentiates causes from things that enable causes to operate as causes. Moreover, he introduces choice of the best as a cause that would operate along with intelligence if all Socrates' actions were caused by intelligence. A choice of the best should be understood as a norm that mediates between intelligence and seeming best. Actions can seem best to someone without in fact being best. Hence, actions can seem best without meeting the conditions prescribed by intelligence. I take it that, for Socrates, to do an action by choice is nothing other than to do an action because it seems best to one. Hence, when someone does what seems best to her, her choice is the cause of what she does. A choice of the best, however, is a choice that meets the conditions prescribed by intelligence, the norm that prescribes the best way to arrange things. A choice of the best, therefore, is a norm prescribing the conditions one's actions must meet if they are both to seem best to one and to be arranged in the best way.
Understanding intelligence, seeming best, and choice of the best as norms not only makes sense of Socrates' discussion of the causes of his sitting in prison, but also of his account of Anaxagoras' cosmic Intelligence. Just as with the intelligence that is normative for human action, Anaxagoras' cosmic Intelligence should be understood as a norm that prescribes the conditions that must be met by whatever is to be arranged in the best way. The hypothesis that Intelligence is the cause of all things amounts to the hypothesis that everything conforms to the norm that prescribes the conditions that whatever is to be arranged in the best way must meet (97c5-6). Hence, the hypothesis that Intelligence is the cause of all things entails that everything is arranged in the best way and presupposes that there is a best way to arrange everything. From the hypothesis that Intelligence is the cause of all things, therefore, Socrates infers that "if one wished to know the cause of each thing... one had to find what was the best way for it to be" (97c6-d1). Thus, if one, granting the hypothesis that Intelligence is the cause of all things, wanted to show that a claim such as "the earth is in the middle of the cosmos" were true, one would show why it was best for the earth to be in the middle of the cosmos (97e3-98a1). Socrates' descriptions of what he hoped for from Anaxagoras are both apt and clear if Anaxagoras' Intelligence is understood as a norm. Moreover, how cosmic Intelligence would cause all things if it were the cause of all things is also clear. Intelligence would cause all things by being a norm that prescribed the conditions all things would meet so as to be arranged in the best way.
On the reading I have been developing, Socrates' critique of Ana xagoras is that Anaxagoras moves from calling a norm-Intelligence-the cause of all things, to calling things causes that are not norms, but are rather objects in space-"airs, aethers, waters, and many others" (98c1-2). Socrates thinks this is tantamount to a failure to distinguish a cause from a thing without which that cause could not be a cause (99b3-4). This is the same distinction one would fail to make if one were to claim that Socrates does what he does because of intelligence-a norm-and were also to claim that he does what he does because of his bones and sinews-objects in space and time rather than norms. Socrates' critique of Anaxagoras, then, is that Anaxagoras should have identified norms when enumerating the causes that worked together with Intelligence to produce all things, instead of identifying spatio-temporal objects. Socrates was originally excited about Anaxagoras because Socrates initially thought that by identifying Intelligence as the cause of all things, Anaxagoras had, in contrast to others among those engaged in the "inquiry into nature," identified a cause that was normative. As Socrates' discussion of his sitting in prison reveals, the causes Socrates considers genuine are normative. His subsequent disappointment arose because of the materialist account of causality Anaxagoras posited when explaining individual phenomena, an account in which the causes were spatio-temporal objects rather than norms.

CAUSES AS NORMS IN THE "SECOND SAILING"
When introducing his "second sailing," Socrates explains that he was neither able to find for himself nor to learn from someone else the truth concerning "such a cause" (99c7; τῆς τοιαύτης αἰτίας) as Anaxagoras' cosmic Intelligence would have been (99c6-d2). If what I said above holds true, Socrates means by this that he was unable to find one norm that by itself could explain why each and every thing comes to be, passes away, and is. 6 Thus, instead of identifying one cause that ordered all things, Socrates posited many causes: the forms (cf. Ebrey, 2014, 252, n. 19). My proposal is that a form, insofar as it is a cause, is a kind of norm. In this way, forms will be causes in the same sense as the genuine causes in Socrates' "first sailing" (Sharma, 2009, 141, n. 5;Ebrey, 2014, 250;pace Shorey, 1933, 179, 534;Vlastos, 1969, 297n15, 302-4;Burge, 1971, 1-2;. The forms, on my reading, are ontological norms that prescribe the conditions a thing must meet in order to be the kind of being that corresponds to the forms in which it participates. Consider some object, x, that has some characteristic, F. Object x is F. Socrates wants to know the cause of x's being F. So he asks, "Why is x F?" Socrates claims that the "safe answer" to questions of this sort is that x is F because x participates in the F itself-form F. By asking why x is F, Socrates is searching for the norm to which object x must conform in order to be an F object. Object x is F insofar as it conforms to that norm. That norm itself is the form F. The forms Socrates focuses on and uses as examples when recounting his "second sailing" are the Beautiful, Greatness, Smallness, Twoness, and Oneness. My claim is that each of these forms is a unique norm that prescribes the conditions a thing must meet in order to be the sort of being that corresponds to each. The form Beautiful, for example, is a norm prescribing the conditions things must meet if they are to be beautiful things, the form Greatness a norm prescribing the conditions things must meet in order to be great things, and so on. Hence, when Socrates says that "if something is beautiful other than the Beautiful itself, it is beautiful because of nothing other than because it participates in that Beautiful (οὐδὲ δι᾽ ἓν ἄλλο καλὸν εἶναι ἢ διότι μετέχει ἐκείνου τοῦ καλοῦ)" (100c4-6), I take him to mean that anything beautiful other than the norm prescribing the conditions a thing must meet in order to be a beautiful thing is beautiful for no other reason than that it conforms to that norm's prescriptions.
In t he case of for ms l i ke Great ness (μέγεθος) and Smallness (σμικρότης), they should be understood as norms that exact a relational structure in their participants. Greatness is a norm prescribing that whatever is to be something great must exceed something else; while Smallness is a norm prescribing that whatever is to be something small must be exceeded by something else (see . Anything other than the form Greatness that is to be great must meet the conditions prescribed by the norm that is the form Greatness by exceeding something else; whereas anything that is to be small must meet the conditions prescribed by the norm that is the form Smallness by being exceeded by something else. Simmias, for example, instantiates the form Greatness insofar as he is taller than Socrates, that is, insofar as his height exceeds the height of Socrates (see Phd. 100e5-101b2, 102b3-d4).
What about forms like Twoness and Oneness (see 101c4-7)? If the forms are norms, then Twoness is a norm prescribing, in the conceptual schema of ancient Greek mathematics, that things that are to be two must be the smallest even number; and, in the conceptual schema of modern mathematics, must be the natural number between one and three. Similarly, Oneness is a norm prescribing, in Greek mathematics, that a thing that is to be one must be a unit, the element out of which numbers are composed; and, in modern mathematics, that a thing that is to be one must be the smallest natural number. Now it might sound strange to our ears to call one apple, for instance, a unit or two apples the smallest even number, but in Greek mathematics a number (ἀριθμός) is a composition of enumerable units and a unit is that "according to which each being is called one (καθ᾽ ἣν ἕκαστον τῶν ὄντων ἓν λέγεται)" (Euc. Elementa, VII, Def. 1-2). Hence, for the Ancient Greeks, an apple is a unit insofar as it is one, and two apples are the number two and the smallest even number insofar as they are two. Nor is it a problem that norms such as Twoness can be described in various ways, for instance in Greek and modern mathematics. The various descriptions are descriptions of one and the same norm. If the forms are ontological norms, they do not depend on how we describe them or the conceptual schema in which we place them. 7 That forms do not depend on how we describe them is not the only way that understanding the forms as ontological norms makes sense of how they are characterized in the dialogues. Forms are characterized (i) as being causally prior to their participants, (ii) as being ontologically prior to sensible particulars, and (iii) as being a-temporal and a-spatial. 8 Let us consider how each of these characteristics fits with reading the forms as norms.
Something A is causally prior B if and only if A explains why B is the sort of thing B is, but B does not explain why A is the sort of thing A is. 9 Given that forms are norms prescribing the conditions a thing must meet in order to be a certain kind of thing, they are causally prior to their participants. Consider again the form Smallness. The norm that is the form Smallness explains why small things are small. They are small because they conform to the norm prescribing that whatever is to be a small thing must be exceeded by something else. It is not the case, however, that small things explain why the norm that is the form Smallness is what it is. Thus, if forms are norms, they are causally prior to their participants.
Something A is ontologically prior to B if and only if A can be what A is whether or A thing's relation to its ref lection in a mirror is a mundane example of ontological priority. There can be no reflection of my body in a mirror unless my body has the visible characteristics it has. Yet my body has the visible characteristics it has regardless of whether or not it is in proximity to a mirror in which it is reflected. Given that forms are norms that prescribe the conditions sensible particulars must meet, it follows that they are ontologically prior to sensible particulars. Consider, for example, the form Bed Socrates discusses in Book 10 of the Republic. If forms are norms, then the form Bed would be a norm prescribing something like the following: something that is to be a bed must be a piece of furniture designed for human beings to sleep on. That norm, however it is properly described, would be what it is even if there were no sensible particular beds. Yet no sensible particular could be a bed if there were no norm Bed prescribing the conditions a thing must meet in order to be a bed. The same point applies to the sorts of forms Socrates discusses in the Phaedo. The norm that is the form Equal, for example, is what it is even if there are no sensible particulars completely identical to one another in quantity. Likewise, the norm that is the form Beautiful would be what it is regardless whether or not there were any sensible particulars conforming to it. In this way, if forms are norms, they are ontologically prior to any sensible particulars that conform to them.
Given that forms, as norms, are ontologically prior to sensible particulars, their a-temporality and a-spatiality also becomes clear. Since the norm that is form F is what it is, regardless of when any sensible particulars that happen to conform to it come into being or pass away, the norm is a-temporal. Similarly, the norm that is form F is not spatially located. The norm applies everywhere and is not an object that could be located in some region of space. Consider the form Greatness. It is everywhere and at all times true that if object A exceeds object B, object A will be greater than object B. The reason for this is that the norm that is the form Greatness is operative everywhere and always, prescribing that anything that exceeds something else is something great relative to what it exceeds. The forms, as ontological norms, are operative at every place and every time. Yet they are not themselves the sorts of things that could be objects in space or subject to time.
My thesis that forms in the Phaedo are best understood as norms is of course independent of my thesis that intelligence, seeming best, and choice of the best in the "first sailing" should be understood as norms. One could reject my interpretation of causality in the "first sailing" and still grant that the forms are norms and that their causal power is their normativity, just as one could reject my interpretation of causality in the "second sailing" and still grant that intelligence, seeming best, and choice of the best in the "first sailing" are norms. While my readings of the "first" and "second sailing" stand or fall independently of one another, if both are correct we get an additional reason to accept each, namely that if they are both correct, Socrates is not simply recounting various views on causality he has considered during his life but is instead using his intellectual biography to develop a single notion of causality to serve as the basis for his final argument for the immortality of the soul.
Nicholas Denyer and Dominic Bailey have pointed out that Socrates does not use any of his typical causal terminology when describing the things that the "more sophisticated answers" identify: fire, a fever, etc. (Denyer, 2007, 93;Bailey, 2014, 24-26;cf. Bolton, 1998, 111). 10 Socrates never refers to them with the word "αἰτία" or its cognates. Likewise, when discussing them, Socrates does not use causal datives, the "διά" plus accusative construction, "διότι," or "ποιεῖν" and its cognates. All the causal language from before is absent here. This should not come as a surprise, since the "more sophisticated answers" do not answer why-questions, but rather what-questions; for example, "what is such that any body in which it is present will be hot?" (105b8-9; ᾧ ἂν τί ἐν τῷ σώματι ἐγγένηται θερμὸν ἔσται). 11 Part of the reason so many commentators have missed this is that the Greek of 105b5-c10 is difficult to translate in a way that properly captures the sense of the kind of question to which the "more sophisticated answers" are answers. Socrates does not propose a new kind of αἰτία in 105b5-c10. Fire, a fever, a unit, and the soul (at least as Socrates considers them here) are neither norms nor causes. 12 generally left the question of the way such teleological causes produce their effects unaddressed. For example, they don't explain the way in which what seems best to Socrates has the power to set his limbs in motion. 5 Socrates presents this claim hypothetically-"as if someone were saying that it is because of intelligence (νῷ) that Socrates does all the things he does. . ." (98c3-4, cf. 99a5-b2)-in order to avoid claiming that all his actions are in fact arranged in the best way. 6 Socrates' claim here in the Phaedo that he was unable to discover for himself or learn from another the sort of cause that Anaxagoras' cosmic Intelligence would have been is compatible with Socrates' own account of cosmic Intelligence as a cause in the Philebus and with his approval of Timaeus' account of cosmic Intelligence as a cause in the Timaeus. In both, Intelligence is not the cause of all things without qualification, but only of good things or of all things insofar as they have measure and proportion (see esp. Phlb. 28d5-30e3, 64c5-e3; Ti. 47e3-5; cf. R. II.379b15-16). 7 This is where my reading differs most sharply from that of Vlastos (1969, see esp. 305-7). 8 For the claim that forms are a-spatial and atemporal see esp. Sym. 211a1, a8-b1. 9 For this formulation see Wiitala (2018, 182); cf. Sedley (1998);Evans (2012). 10 For a discussion of Socrates' causal terminology, see Sedley (1998, 115). 11 The translation is that of Denyer (2007, 93); see also Bailey (2014, 25