After a short digression, in which Cicero discusses the merits (and disadvantages) of philosophy, he turns his attention to a discussion of the discovery of arguments. Cicero maintains (through Antonius) that an essential facet of the orator’s education would include bringing the nascent orator
to that source where no sequestered pool is landlocked, but from it bursts forth a general flood; to that teacher who will point out to him the very homes of all proofs, so to speak, illustrating these briefly and defining them in terms. (2.39.162)
These proofs would include those that are “derived from the essential nature of the case” and those “adopted from without” (2.39.163), a dichotomy that was also emphasized in Inv. Cicero further defines these two ideas:
Intrinsic arguments, when the problem concerns the character of the subject as a whole, or of part of it, or the name it is to bear or anything whatever relating to the subject; extrinsic arguments, on the other hand, when topics are assembled from without and are not inherent in the nature of the case. (2.39.163)
What follows is in a similar format to the materials in Inv.; Cicero lists arguments available for use in various cases, starting first with the intrinsic and finishing with the extrinsic. He then concludes the discussion:
I [Antonius] have sketched these topics as shortly as possible. For if I wished to reveal to somebody gold that was hidden here and there in the earth, it should be enough for me to point out to him some marks and indications of its positions, with which knowledge he could do his own digging, and find what he wanted, with very little trouble and no chance of mistake: so I know these indications of proofs, which reveal to me their whereabouts when I am looking for them; all the rest is dug out by dint of careful consideration . . . with these commonplaces [locis] firmly established in his mind and memory, and roused into activity with every topic proposed for discussion, nothing will be able to elude the orator either in our own contentions at the Bar, or in any department whatever of speaking. (2.91.174–75)
Concerning the evidence found in De or., the concept of locus is described in much the same way as in Inv. Loci are described as sources of arguments which are either inherent in the case being argued or external to the case. The various loci are available to the orator, and must only be applied to the case being argued. Cicero purposely links the concept to Aristotle, but his descriptions of the various loci demonstrate that for Cicero, unlike in Aristotle, the loci constitute the content of the arguments, rather than their form.122
Cicero provides the most detailed explanation of a locus in his work Topica.123 In the beginning of this treatise, Cicero opens a dialog with Trebatius, a jurist who has sometime in the past happened upon Aristotle’s Topica and questioned Cicero concerning Aristotle’s work. Cicero notes, “And when I had made clear to you that these books contained a system developed by Aristotle for inventing arguments so that we might come upon them by a rational system without wandering about, you begged me to teach you the subject” (Top. 1.2). Thus, with this introduction, Cicero sets out to explain his interpretation of Aristotle’s system of topoi.124
Cicero first provides a definition for locus:
A comparison may help: It is easy to find things that are hidden if the hiding place is pointed out and marked; similarly if we wish to track down some argument we ought to know the places or topics: for that is the name given by Aristotle to the “regions,” as it were, from which arguments are drawn. Accordingly, we may define a topic [definire locum] as the region of an argument, and an argument as a course of reasoning which firmly establishes a matter about which there is some doubt. (Top. 2.7–8)
From this definition one notices that Cicero links his concept of locus to that of Aristotle.125 What is also clear is that Cicero considers loci to be sources of arguments; as in De or., the locus itself is the place or region of a particular argument.126
Following this definition, Cicero states that the loci can be divided into two categories: “Of the topics [locis] under which arguments are included, some are inherent in the very nature of the subject which is under discussion, and others are brought in from without” (2.8). Again, as was seen in the previous treatises, Cicero argues that there are internal and external loci. Internal loci are particular to the subject matter which is being argued; external loci must be derived from sources outside of the subject itself. The next section of the treatise (2.9—4.23) provides an elaboration of the internal loci. Among others, these include arguments from genus and species, arguments based on similarity and difference, and arguments from consequences and effects. After all the internal loci have been listed and briefly described,127 Cicero makes only a short statement concerning external loci. He asserts, “Extrinsic arguments depend principally on authority. Therefore, the Greeks call such means of argumentation ἄτεχνοι, that is, not invented by the art of the orator” (4.24). He then provides an example of an extrinsic argument, namely the testimony of one with knowledge of the law.
A final piece of evidence which helps illuminate Cicero’s concept of a locus is found in his treatise Partitiones oratoriae. The treatise is composed as a dialog between Cicero and his son. The younger Cicero asks the elder what the overall purpose of the orator is, to which the elder answers, “To discover how to convince the persons whom he wishes to persuade and how to arouse their emotions” (2.5). In answer to the question concerning through what method one is able to persuade, the elder Cicero states, “Arguments, which are derived from topics [ex locis] that are either contained in the facts of the case itself or are obtained from outside” (2.5). The younger Cicero then asks about topics [Quos vocas locos?], to which the elder answers, “Pigeonholes in which arguments are stored” (2.5). Later, one reads that the elder Cicero maintains the same differentiation between “internal” and “external” arguments, which are described as arguments inherent to the case itself (internal) and testimony (external).
After describing the evidence of witnesses and testimony, a topic to which we will return, the elder Cicero then lists several loci from which internal arguments can be drawn, a list that is similar to the loci described in detail in Top. [Part. or. 2.7; cf. Top. 2.8—4.23; 5.26—18.71]. The younger Cicero then asks if all the loci are to be used when arguing a case. The answer he receives is that the orator should
examine them and seek for arguments from them all; but we shall use our judgment always to reject those of little value and also sometimes to pass over those that are of general application and not intimately related to our case. (Part. or. 3.8)
Here one notes that the loci are not only sources of arguments for Cicero; they also provide a methodology for evaluating the appropriateness of a particular set of arguments.
In summarizing Cicero’s concept of locus as found in his rhetorical treatises, Cicero considers the loci to be the sources of arguments for an orator arguing a case. In particular, Cicero is focused on what was indeed the emphasis in his own career, namely arguing mostly forensic cases in service to the State. The loci can be subdivided into internal and external arguments, internal arguments being those that are connected to the facts of the case being argued; external arguments are those from outside the case and are mostly concerned with witnesses and testimony. These various loci are concerned with the contents of the arguments themselves, and are to be scrutinized by the orator in order to assist in the process of crafting the most persuasive speech possible.128 Thus, there is an emphasis in Cicero on the practicality and utility of the loci, rather than the theory of argumentation as was seen in Aristotle.129
While this is certainly the primary sense