[7] Diog. III. 86.
[8] Pappenheim _Gr. Pyrr. Grundzuge_, p. 50.
[9] _Hyp._ I. 163.
[10] Diog. IX. 11, 83.
Following the exposition of the ten Tropes of the older Sceptics, s.e.xtus gives the five Tropes which he attributes to the "later Sceptics."[1] s.e.xtus nowhere mentions the author of these Tropes. Diogenes, however, attributes them to Agrippa, a man of whom we know nothing except his mention of him. He was evidently one of the followers of Aenesidemus, and a scholar of influence in the Sceptical School, who must have himself had disciples, as Diogenes says, [Greek: hoi peri Agrippan][2] add to these tropes other five tropes, using the plural verb.
Another Sceptic, also mentioned by Diogenes, and a man unknown from other sources, named some of his books after Agrippa.[3]
Agrippa is not given by Diogenes in the list of the leaders of the Sceptical School, but[4] his influence in the development of the thought of the School must have been great, as the transition from the ten Tropes of the "older Sceptics" to the five attributed to Agrippa is a marked one, and shows the entrance into the school of a logical power before unknown in it. The latter are not a reduction of the Tropes of Aenesidemus, but are written from an entirely different standpoint. The ten Tropes are empirical, and aim to furnish objective proofs of the foundation theories of Pyrrhonism, while the five are rather rules of thought leading to logical proof, and are dialectic in their character. We find this distinction ill.u.s.trated by the different way in which the Trope of relativity is treated in the two groups. In the first it points to an objective relativity, but with Agrippa to a general subjective logical principle. The originality of the Tropes of Agrippa does not lie in their substance matter, but in their formulation and use in the Sceptical School. These methods of proof were, of course, not new, but were well known to Aristotle, and were used by the Sceptical Academy, and probably also by Timon,[5] while the [Greek: pros ti] goes back at least to Protagoras. The five Tropes are as follows.
(i) The one based upon discord.
(ii) The _regressus in infinitum_.
(iii) Relation.
(iv) The hypothetical.
(v) The _circulus in probando_.
Two of these are taken from the old list, the first and the third, and s.e.xtus says that the five Tropes are intended to supplement the ten Tropes, and to show the audacity of the Dogmatics in a variety of ways.[6] The order of these Tropes is the same with Diogenes as with s.e.xtus, but the definitions of them differ sufficiently to show that the two authors took their material from different sources. According to the first one everything in question is either sensible or intellectual, and in attempting to judge it either in life, practically, or "among philosophers," a position is developed from which it is impossible to reach a conclusion.[7] According to the second, every proof requires another proof, and so on to infinity, and there is no standpoint from which to begin the reasoning.[8]
According to the third, all perceptions are relative, as the object is colored by the condition of the judge, and the influence of other things around it.[9] According to the fourth, it is impossible to escape from the _regressus in infinitum_ by making a hypothesis the starting point, as the Dogmatics attempt to do.[10] And the fifth, or the _circulus in probando_, arises when that which should be the proof needs to be sustained by the thing to be proved.
[1] _Hyp._ I. 164.
[2] Diog. IX. 11, 88.
[3] Diog. IX. 11, 106.
[4] Diog. IX. 12, 115-116.
[5] Compare Natorp. _Op. cit._ p. 302.
[6] _Hyp._ I. 177.
[7] _Hyp._ I. 165.
[8] _Hyp._ I. 166.
[9] _Hyp._ I. 167.
[10] _Hyp._ I. 168.
s.e.xtus claims that all things can be included in these Tropes, whether sensible or intellectual.[1] For whether, as some say, only the things of sense are true, or as others claim, only those of the understanding, or as still others contend, some things both of sense and understanding are true, a discord must arise that is impossible to be judged, for it cannot be judged by the sensible, nor by the intellectual, for the things of the intellect themselves require a proof; accordingly, the result of all reasoning must be either hypothetical, or fall into the _regressus in infinitum_ or the _circulus in probando_.[2] The reference above to some who say that only the things of sense are true, is to Epicurus and Protagoras; to some that only the things of thought are true, to Democritus and Plato; and to those that claimed some of both to be true, to the Stoics and the Peripatetics.[3] The three new Tropes added by Agrippa have nothing to do with sense-perception, but bear entirely upon the possibility of reasoning, as demanded by the science of logic, in contrast to the earlier ones which related almost entirely, with the exception of the tenth, to material objects. s.e.xtus claims that these five Tropes also lead to the suspension of judgment,[4] but their logical result is rather the dogmatic denial of all possibility of knowledge, showing as Hirzel has well demonstrated, far more the influence of the New Academy than the spirit of the Sceptical School.[5] It was the standpoint of the older Sceptics, that although the search for the truth had not yet succeeded, yet they were still seekers, and s.e.xtus claims to be faithful to this old aim of the Pyrrhonists. He calls himself a seeker,[6] and in reproaching the New Academy for affirming that knowledge is impossible, s.e.xtus says, "Moreover, we say that our ideas are equal as regards trustworthiness and untrustworthiness."[7] The ten Tropes claim to establish doubt only in regard to a knowledge of the truth, but the five Tropes of Agrippa aim to logically prove the impossibility of knowledge. It is very strange that s.e.xtus does not see this decided contrast in the att.i.tude of the two sets of Tropes, and expresses his approval of those of Agrippa, and makes more frequent use of the fifth of these, [Greek: ho diallelos], in his subsequent reasoning than of any other argument.[8]
[1] _Hyp._ I. 169.
[2] _Hyp._ I. 170-171.
[3] _Adv. Math._ VIII. 185-186; VIII. 56; VII. 369.
[4] _Hyp._ I. 177.
[5] Hirzel _Op. cit._ p. 131.
[6] _Hyp._ I. 3, 7.
[7] _Hyp._ I. 227.
[8] See Index of Bekker"s edition of s.e.xtus" works.
We find here in the Sceptical School, shortly after the time of Aenesidemus, the same tendency to dogmatic teaching that--so far as the dim and shadowy history of the last years of the New Academy can be unravelled, and the separation of Pyrrhonism can be understood, at the time that the Academy pa.s.sed over into eclecticism--was one of the causes of that separation.
It is true that the Tropes of Agrippa show great progress in the development of thought. They furnish an organisation of the School far superior to what went before, placing the reasoning on the firm basis of the laws of logic, and simplifying the amount of material to be used. In a certain sense Saisset is correct in saying that Agrippa contributed more than any other in completing the organisation of Scepticism,[1] but it is not correct when we consider the true spirit of Scepticism with which the Tropes of Agrippa were not in harmony. It was through the very progress shown in the production of these Tropes that the school finally lost the strength of its position.
Not content with having reduced the number of the Tropes from ten to five, others tried to limit the number still further to two.[2] s.e.xtus gives us no hint of the authorship of the two Tropes. Ritter attributes them to Menodotus and his followers, and Zeller agrees with that opinion,[3] while Saisset thinks that Agrippa was also the author of these,[4] which is a strange theory to propound, as some of the material of the five is repeated in the two, and the same man could certainly not appear as an advocate of five, and at the same time of two Tropes.
[1] Saisset _Op. cit._ p. 237.
[2] _Hyp._ I. 178.
[3] Zeller III. 38; Ritter IV. 277.
[4] Saisset _Op. cit._ p. 231.
The two Tropes are founded on the principle that anything must be known through itself or through something else. It cannot be known through itself, because of the discord existing between all things of the senses and intellect, nor can it be known through something else, as then either the _regressus in infinitum_ or the _circulus in probando_ follow.[1] Diogenes Laertius does not refer to these two Tropes.
In regard to all these Tropes of the suspension of judgment, s.e.xtus has well remarked in his introduction to them, that they are included in the eighth, or that of relation.[2]
[1] _Hyp._ I. 178-179.
[2] _Hyp._ I. 39.
_The Tropes of Aetiology_. The eight Tropes against causality belong chronologically before the five Tropes of Agrippa, in the history of the development of sceptical thought. They have a much closer connection with the spirit of Scepticism than the Tropes of Agrippa, including, as they do, the fundamental thought of Pyrrhonism, _i.e._, that the phenomena do not reveal the unknown.
The Sceptics did not deny the phenomena, but they denied that the phenomena are signs capable of being interpreted, or of revealing the reality of causes. It is impossible by a research of the signs to find out the unknown, or the explanation of things, as the Stoics and Epicureans claim. The theory of Aenesidemus which lies at the foundation of his eight Tropes against aetiology, is given to us by Photius as follows:[1]
"There are no visible signs of the unknown, and those who believe in its existence are the victims of a vain illusion."
This statement of Aenesidemus is confirmed by a fuller explanation of it given later on by s.e.xtus.[2] If phenomena are not signs of the unknown there is no causality, and a refutation of causality is a proof of the impossibility of science, as all science is the science of causes, the power of studying causes from effects, or as s.e.xtus calls them, phenomena.
It is very noticeable to any one who reads the refutation of causality by Aenesidemus, as given by s.e.xtus,[3] that there is no reference to the strongest argument of modern Scepticism, since the time of Hume, against causality, namely that the origin of the idea of causality cannot be so accounted for as to justify our relying upon it as a form of cognition.[4]
[1] _Myriob._ 170 B. 12.
[2] _Adv. Math._ VIII. 207.
[3] _Hyp._ I. 180-186.
[4] Ueberweg _Op. cit._ p. 217.
The eight Tropes are directed against the possibility of knowledge of nature, which Aenesidemus contested against in all his Tropes, the ten as well as the eight.[1] They are written from a materialistic standpoint. These Tropes are given with ill.u.s.trations by Fabricius as follows: