[180] Just as we teach the traditional Modes leading to suspense of judgement, so likewise some Sceptics propound Modes by which we express doubt about the particular ‟aetiologies,” or theories of causation, and thus pull up the Dogmatists because of the special pride they take in these theories. Thus Aenesidemus furnishes us with Eight Modes by which, as he thinks, he tests and exposes the unsoundness of every dogmatic theory of causation.

[181] Of these the First, he says, is that which shows that, since aetiology as a whole deals with the non-apparent, it is unconfirmed by any agreed evidence derived from appearances. The Second Mode shows how often, when there is ample scope for ascribing the object of investigation to a variety of causes, some of them account for it in one way only.

[182] The Third shows how to orderly events they assign causes which exhibit no order. The Fourth shows how, when they have grasped the way in which appearances occur, they assume that they have also apprehended how non-apparent things occur, whereas, though the non-apparent may possibly be realized in a similar way to the appearances, possibly they may not be realized in a similar way but in a peculiar way of their own.

[183] In the Fifth Mode it is shown how practically all these theorists assign causes according to their own particular hypotheses about the elements, and not according to any commonly agreed methods. In the Sixth it is shown how they frequently admit only such facts as can be explained by their own theories, and dismiss facts which conflict therewith though possessing equal probability.

[184] The Seventh shows how they often assign causes which conflict not only with appearances but also with their own hypotheses. The Eighth shows that often, when there is equal doubt about things seemingly apparent and things under investigation, they base their doctrine about things equally doubtful upon things equally doubtful.

[185] Nor is it impossible, he adds, that the overthrow of some of their theories of causation should be referred to certain mixed Modes which are dependent on the foregoing.

Possibly, too, the Five Modes of suspension ¹ may suffice as against the aetiologies. For if a person propounds a cause, it will either be or not be in accord with all the philosophical systems and with Scepticism and with appearances. Probably, however, it is impracticable to propound a cause in accord with all these, since all things, whether apparent or non- evident, are matters of controversy.

[186] But if, on the other hand, the cause propounded be not in accord therewith, the theorist will be asked in turn for the cause of this cause, and if he assumes an apparent cause for an apparent, or a non-evident for a non- evident, he will be involved in the regress ad infinitum, or reduced to arguing in a circle if he grounds each cause in turn on another. And if at any point he makes a stand, either he will state that the cause is well-grounded so far as relates to the previous admissions, thus introducing relativity and destroying its claim to absolute reality, or he will make some assumption ex hypothesi and will be stopped by us. So by these Modes also it is, no doubt, possible to expose the rashness of the Dogmatists in their aetiologies.