We will first show that it is not _perception_. Now perception is held to be of two kinds, external and internal [_i.e._, as produced by the external senses, or by the inner sense, mind]. The former is not the required means; for although it is possible that the actual contact of the senses and the object will produce the knowledge of the particular object thus brought in contact, yet as there can never be such contact in the case of the past or the future, the universal proposition[15] which was to embrace the invariable connection of the middle and major terms in every case becomes impossible to be known. Nor may you maintain that this knowledge of the universal proposition has the general class as its object, because if so, there might arise a doubt as to the existence of the invariable connection in this particular case[16] [as, for instance, in this particular smoke as implying fire]. Nor is internal perception the means, since you cannot establish that the mind has any power to act independently towards an external object, since all allow that it is dependent on the external senses, as has been said by one of the logicians, "The eye, &c., have their objects as described; but mind externally is dependent on the others." Nor can _inference_ be the means of the knowledge of the universal proposition, since in the case of this inference we should also require another inference to establish it, and so on, and hence would arise the fallacy of an _ad infinitum_ retrogression. Nor can _testimony_ be the means thereof, since we may either allege in reply, in accordance with the Vaiśeshika doctrine of Kaṇáda, that this is included in the topic of inference; or else we may hold that this fresh proof of testimony is unable to leap over the old barrier that stopped the progress of inference, since it depends itself on the recognition of a _sign_ in the form of the language used in the child's presence by the old man;[17] and, moreover, there is no more reason for our believing on another's word that smoke and fire are invariably connected, than for our receiving the _ipse dixit_ of Manu, &c. [which, of course, we Chárvákas reject]. And again, if testimony were to be accepted as the only means of the knowledge of the universal proposition, then in the case of a man to whom the fact of the invariable connection between the middle and major terms had not been pointed out by another person, there could be no inference of one thing [as fire] on seeing another thing [as smoke]; hence, on your own showing, the whole topic of inference for oneself[18] would have to end in mere idle words.