in the _womb_, why should not simultaneousness of birth allow of any two individuals having different fortunes in the _world_? and thus would all the fictions of this art, or rather delusion, be swept away. What strange circumstance is this, that two children conceived at the same time, nay, at the same moment, under the same position of the stars, have different fates which bring them to different hours of birth, whilst two children, born of two different mothers, at the same moment of time, under one and the same position of the stars, cannot have different fates which shall conduct them by necessity to diverse manners of life and of death? Are they at conception as yet without destinies, because they can only have them if they be born? What, therefore, do they mean when they say that, if the hour of the conception be found, many things can be predicted by these astrologers? from which also arose that story which is reiterated by some, that a certain sage chose an hour in which to lie with his wife, in order to secure his begetting an illustrious son. From this opinion also came that answer of Posidonius, the great astrologer and also philosopher, concerning those twins who were attacked with sickness at the same time, namely, "That this had happened to them because they were conceived at the same time, and born at the same time." For certainly he added "conception," lest it should be said to him that they could not both be _born_ at the same time, knowing that at any rate they must both have been conceived at the same time; wishing thus to show that he did not attribute the fact of their being similarly and simultaneously affected with sickness to the similarity of their bodily constitutions as its proximate cause, but that he held that even in respect of the similarity of their health, they were bound together by a sidereal connection. If, therefore, the time of conception has so much to do with the similarity of destinies, these same destinies ought not to be changed by the circumstances of birth; or, if the destinies of twins be said to be changed because they are born at different times, why should we not rather understand that they had been already changed in order that they might be born at different times? Does not, then, the will of men living in the world change the destinies of birth, when the order of birth can change the destinies they had at conception? 6. _Concerning twins of different sexes._