fallacies, then, that depend on accident occur whenever any attribute is claimed to belong in like manner to a thing and to its accident. for since the same thing has many accidents there is no necessity that all the same attributes should belong to all of a thing’s predicates and to their subject as well. thus (e.g.), ‘if coriscus be different from “man”, he is different from himself: for he is a man’: or ‘if he be different from socrates, and socrates be a man, then’, they say, ‘he has admitted that coriscus is different from a man, because it so happens (accidit) that the person from whom he said that he (coriscus) is different is a man’.

those that depend on whether an expression is used absolutely or in a certain respect and not strictly, occur whenever an expression used in a particular sense is taken as though it were used absolutely, e.g. in the argument ‘if what is not is the object of an opinion, then what is not is’: for it is not the same thing ‘to be x’ and ‘to be’ absolutely. or again, ‘what is, is not, if it is not a particular kind of being, e.g. if it is not a man.’ for it is not the same thing ‘not to be x’ and ‘not to be’ at all: it looks as if it were, because of the closeness of the expression, i.e. because ‘to be x’ is but little different from ‘to be’, and ‘not to be x’ from ‘not to be’. likewise also with any argument that turns upon the point whether an expression is used in a certain respect or used absolutely. thus e.g. ‘suppose an indian to be black all over, but white in respect of his teeth; then he is both white and not white.’ or if both characters belong in a particular respect, then, they say, ‘contrary attributes belong at the same time’. this kind of thing is in some cases easily seen by any one, e.g. suppose a man were to secure the statement that the ethiopian is black, and were then to ask whether he is white in respect of his teeth; and then, if he be white in that respect, were to suppose at the conclusion of his questions that therefore he had proved dialectically that he was both white and not white. but in some cases it often passes undetected, viz. in all cases where, whenever a statement is made of something in a certain respect, it would be generally thought that the absolute statement follows as well; and also in all cases where it is not easy to see which of the attributes ought to be rendered strictly. a situation of this kind arises, where both the opposite attributes belong alike: for then there is general support for the view that one must agree absolutely to the assertion of both, or of neither: e.g. if a thing is half white and half black, is it white or black?

other fallacies occur because the terms ‘proof’ or ‘refutation’ have not been defined, and because something is left out in their definition. for to refute is to contradict one and the same attribute-not merely the name, but the reality-and a name that is not merely synonymous but the same name-and to confute it from the propositions granted, necessarily, without including in the reckoning the original point to be proved, in the same respect and relation and manner and time in which it was asserted. a ‘false assertion’ about anything has to be defined in the same way. some people, however, omit some one of the said conditions and give a merely apparent refutation, showing (e.g.) that the same thing is both double and not double: for two is double of one, but not double of three. or, it may be, they show that it is both double and not double of the same thing, but not that it is so in the same respect: for it is double in length but not double in breadth. or, it may be, they show it to be both double and not double of the same thing and in the same respect and manner, but not that it is so at the same time: and therefore their refutation is merely apparent. one might, with some violence, bring this fallacy into the group of fallacies dependent on language as well.

those that depend on the assumption of the original point to be proved, occur in the same way, and in as many ways, as it is possible to beg the original point; they appear to refute because men lack the power to keep their eyes at once upon what is the same and what is different.

the refutation which depends upon the consequent arises because people suppose that the relation of consequence is convertible. for whenever, suppose a is, b necessarily is, they then suppose also that if b is, a necessarily is. this is also the source of the deceptions that attend opinions based on sense-perception. for people often suppose bile to be honey because honey is attended by a yellow colour: also, since after rain the ground is wet in consequence, we suppose that if the ground is wet, it has been raining; whereas that does not necessarily follow. in rhetoric proofs from signs are based on consequences. for when rhetoricians wish to show that a man is an adulterer, they take hold of some consequence of an adulterous life, viz. that the man is smartly dressed, or that he is observed to wander about at night. there are, however, many people of whom these things are true, while the charge in question is untrue. it happens like this also in real reasoning; e.g. melissus’ argument, that the universe is eternal, assumes that the universe has not come to be (for from what is not nothing could possibly come to be) and that what has come to be has done so from a first beginning. if, therefore, the universe has not come to be, it has no first beginning, and is therefore eternal. but this does not necessarily follow: for even if what has come to be always has a first beginning, it does not also follow that what has a first beginning has come to be; any more than it follows that if a man in a fever be hot, a man who is hot must be in a fever.

the refutation which depends upon treating as cause what is not a cause, occurs whenever what is not a cause is inserted in the argument, as though the refutation depended upon it. this kind of thing happens in arguments that reason ad impossible: for in these we are bound to demolish one of the premisses. if, then, the false cause be reckoned in among the questions that are necessary to establish the resulting impossibility, it will often be thought that the refutation depends upon it, e.g. in the proof that the ‘soul’ and ‘life’ are not the same: for if coming-to-be be contrary to perishing, then a particular form of perishing will have a particular form of coming-to-be as its contrary: now death is a particular form of perishing and is contrary to life: life, therefore, is a coming to-be, and to live is to come-to-be. but this is impossible: accordingly, the ‘soul’ and ‘life’ are not the same. now this is not proved: for the impossibility results all the same, even if one does not say that life is the same as the soul, but merely says that life is contrary to death, which is a form of perishing, and that perishing has ‘coming-to-be’ as its contrary. arguments of that kind, then, though not inconclusive absolutely, are inconclusive in relation to the proposed conclusion. also even the questioners themselves often fail quite as much to see a point of that kind.

such, then, are the arguments that depend upon the consequent and upon false cause. those that depend upon the making of two questions into one occur whenever the plurality is undetected and a single answer is returned as if to a single question. now, in some cases, it is easy to see that there is more than one, and that an answer is not to be given, e.g. ‘does the earth consist of sea, or the sky?’ but in some cases it is less easy, and then people treat the question as one, and either confess their defeat by failing to answer the question, or are exposed to an apparent refutation. thus ‘is a and is b a man?’ ‘yes.’ ‘then if any one hits a and b, he will strike a man’ (singular),’not men’ (plural). or again, where part is good and part bad, ‘is the whole good or bad?’ for whichever he says, it is possible that he might be thought to expose himself to an apparent refutation or to make an apparently false statement: for to say that something is good which is not good, or not good which is good, is to make a false statement. sometimes, however, additional premisses may actually give rise to a genuine refutation; e.g. suppose a man were to grant that the descriptions ‘white’ and ‘naked’ and ‘blind’ apply to one thing and to a number of things in a like sense. for if ‘blind’ describes a thing that cannot see though nature designed it to see, it will also describe things that cannot see though nature designed them to do so. whenever, then, one thing can see while another cannot, they will either both be able to see or else both be blind; which is impossible.