[1] Since we have undertaken this inquiry in criticism of the Dogmatists, ¹ let us review briefly and in outline the several divisions of so-called philosophy, when we have first made reply to those who keep constantly repeating that the Sceptic is incapable of either investigating or in any way cognizing the objects about which they dogmatize.

[2] For they ² maintain that the Sceptic either apprehends or does not apprehend the statements made by the Dogmatists; if, then, he apprehends, how can he be perplexed about things which he has, as he says, apprehended? Whereas if he apprehends not, then neither does he know how to discuss matters which he has not apprehended.

[3] For just as he who is ignorant, for instance, of the arguments known as ‟How far reduced” ³ or ‟By two hypotheses,” ⁴ is unable also to say anything about them, so the man who does not know each of the statements made by the Dogmatists is unable to criticize them concerning matters of which he has no knowledge. Thus the Sceptic is wholly incapable of investigating the statements made by the Dogmatists.

[4] Now let those who speak thus make answer and tell us in what sense they are now using the term ‟apprehend,” whether simply of mental conception without the further affirmation of the reality of the objects under discussion, or with the further assumption of the reality of the objects discussed. For if they say that ‟to apprehend” means, in their argument, to assent to an ‟apprehensive impression,” ⁵ the apprehensive impression being derived from a real object and being an imprint or stamp upon the mind corresponding to the actual object, such as would not result from what is unreal, then probably not even they themselves will wish to allow their inability to investigate things which, in this sense, they have not apprehended.

[5] Thus, for example, when the Stoic criticizes the statement of the Epicurean that ‟Being is divided,” ⁶ or that ‟God does not foreknow events in the Universe,” or that ‟Pleasure is the Good,” has he apprehended or has he not apprehended? If he has apprehended these dogmas, by asserting their real truth he entirely overthrows the Porch; while if he has not apprehended them, he is unable to say anything against them.

[6] And we must use a like argument against those who issue from any of the other Sects, whenever they desire to make any critical investigation of the tenets of those who differ from them in doctrine. consequently they are debarred from indulging in any criticism of one another. Or rather—to avoid talking nonsense—practically the whole of Dogmatism will be confounded and the Sceptic philosophy will be firmly established once it is granted that it is impossible to inquire regarding an object which is not, in this sense, apprehended.

[7] For he who makes a dogmatic statement about a non-evident object will declare that he is making it either after having apprehended or after having not apprehended it. But if he has not apprehended it he will not gain credence; while if he has apprehended it, he will say that he has apprehended the object directly and through itself and owing to the clear impression it has made on him, or else by means of some kind of search and inquiry. ⁷

[8] But if he shall say that the non-evident object has impressed him and has been apprehended through itself, immediately and clearly, in this case the object would not be non-evident but apparent to all men equally, an acknowledged and uncontroverted fact. But about every single object that is non-evident there exists amongst them endless controversy; so that the Dogmatist who makes positive assertions about the reality of a non-evident object cannot have apprehended it because of its having made on him a direct and clear impression.

[9] If, on the other hand, his apprehension is a result of search, how was he in a position to make inquiry before he had accurately apprehended the object, without violating our present assumption? For since the inquiry necessitates as a preliminary the existence of an accurate apprehension of that which is to be the subject of inquiry, while the apprehension of the subject of inquiry demands, in its turn, the previous existence of a complete inquiry into that subject, owing to this circular process of reasoning ⁸ it becomes impossible for them either to inquire concerning things non-evident or to dogmatize; for if some of them wish to make apprehension their starting- point we force them to grant that the object must be investigated before it is apprehended, while if they start from inquiry we make them admit that before inquiring they must apprehend the object of the inquiry, so that for these reasons they can neither apprehend any non-evident object nor make positive statements about them. From this there will follow automatically, as I think, the demolition of the Dogmatic sophistry ⁹ and the establishment of the Suspensive philosophy.

[10] If, however, they say that it is not this kind of apprehension that ought, in their view, to precede inquiry, but simply mental conception, then it is no longer impossible for those who suspend judgement to inquire about the reality of things non-evident. For the Sceptic is not, I suppose, prohibited from mental conception which arises through the reason itself as a result of passive impressions and clear appearances and does not at all involve the reality of the objects conceived; for we conceive, as they say, not only of real things but also of unreal. Hence both while inquiring and while conceiving the Suspensive person continues in the Sceptical state of mind. For, as has been shown, he assents to what he experiences by way of subjective impression, according as that impression appears to him.

[11] But consider whether, even in this case, the Dogmatists are not precluded from inquiry. For to continue the investigation of problems is not inconsistent in those who confess their ignorance of their real nature, but only in those who believe they have an exact knowledge of them; since for the latter the inquiry has already, as they suppose, reached its goal, whereas for the former the ground on which all inquiry is based—namely, the belief that they have not found the truth—still subsists.

[12] Thus we have to inquire briefly, on the present occasion, concerning each several division of philosophy so called. And since there exists much dispute amongst the Dogmatists regarding the divisions of philosophy ¹⁰ —some saying there is one division, some two, some three—and it would not now be convenient to discuss the question at length, we will explain fairly and impartially the view of those who seem to have treated it most fully, and take their view as the subject of our discourse.