That only Man hath an Erect figure, and for to behold and look up toward heaven, according to that of the Poet,
Pronaque cum spectant animalia cætera terram,
Os homini sublime dedit, cælumque tueri
Jussit, et erectos ad sydera tollere vultus,
is a double assertion, whose first part may be true, if we take Erectness strictly, and so as Galen hath defined it; for they only, saith he, have an Erect figure, whose spine and thigh-bone are carried in right lines; and so indeed of any we yet know, Man only is Erect. For the thighs of other animals do stand at Angles with their spine, and have rectangular positions in Birds, and perfect Quadrupeds. Nor doth the Frog, though stretched out, or swimming, attain the rectitude of Man, or carry its thigh without all angularity. What seiante or sitting. And thus is it also true, that Man only sitteth, if we define sitting to be a firmation of the body upon the Ischias: wherein if the position be just and natural, the Thigh-bone lieth at right angles to the Spine, and the Leg-bone or Tibia to the Thigh. For others when they seem to sit, as Dogs, Cats, or Lions, do make unto their Spine acute angles with their Thigh, and acute to the Thigh with their Shank. Thus is it likewise true, what Aristotle alledgeth in that Problem; why Man alone suffereth pollutions in the Night, ἐξονειρωκτικός. because Man only lyeth upon his Back; if we define not the same by every supine position, but when the Spine is in rectitude with the Thigh, and both with the arms lie parallel to the Horizon: so that a line through their Navel will pass through the Zenith and Centre of the Earth. And so cannot other Animals lie upon their Backs: for though the Spine lie parallel with the Horizon, yet will their Legs incline, and lie at angles unto it. And upon these three divers positions in Man, wherein the Spine can only be at right lines with the Thigh, arise those remarkable postures, prone, supine and erect; which are but differenced in situation, or in angular postures upon the Back, the Belly and the Feet.
But if Erectness be popularly taken, and as it is largely opposed unto proneness, or the posture of animals looking downwards, carrying their venters or opposite part to the Spine, directly towards the Earth, it may admit of question. For though in Serpents and Lizards we may truly allow a proneness, yet Galen acknowledgeth that perfect Quadrupeds, as Horses, Oxen and Camels, are but partly prone, and have some part of Erectness. And Birds or flying Animals, are so far from this kind of proneness, that they are almost Erect; advancing the Head and Breast in their progression, and only prone in the Act of volitation or flying. And if that be true which is delivered of the Pengin or Anser Magellanicus, often described in Maps about those Straits, that they go Erect like Men, and with their Breast and Belly do make one line perpendicular unto the axis of the Earth; it will almost make up the exact Erectness of Man. Observe also the Vrias Bellanii and Mergus major. Nor will that Insect come very short which we have often beheld, that is, one kind of Locust which stands not prone, or a little inclining upward, but in a large Erectness, elevating alwaies the two fore Legs, and sustaining it self in the middle of the other four: by Zoographers Describers of animals. called Mantis, and by the common people of Provence, Prega, Dio, the Prophet and praying Locust; as being generally found in the posture of supplication, or such as resembleth ours, when we lift up our hands to Heaven.
As for the end of this Erection; to look up toward Heaven; though confirmed by several testimonies, and the Greek Etymology of Man, it is not so readily to be admitted; and as a popular and vain conceit was Anciently rejected by Galen; who in his third, De usu partium, determines, that Man is Erect, because he was made with hands, and was therewith to exercise all Arts, which in any other figure he could not have performed; as he excellently declareth in that place, where he also proves that Man could have been made neither Quadruped nor Centaur.
And for the accomplishment of this intention, that is, to look up and behold the Heavens, Man hath a notable disadvantage in the Eye lid; whereof the upper is far greater than the lower, which abridgeth the sight upwards; contrary to those of Birds, who herein have the advantage of Man: Insomuch that the Learned PlempiusPlemp. Ophthalmographia. is bold to affirm, that if he had had the formation of the Eye-lids, he would have contrived them quite otherwise.
The ground and occasion of this conceit was a literal apprehension of a figurative expression in Plato, as Galen thus delivers; To opinion that Man is Erect to look up and behold the Heavens, is a conceit only fit for those that never saw the Fish Uranoscopus, that is, the Beholder of Heaven; which hath its Eyes so placed, that it looks up directly to Heaven; which Man doth not, except he recline, or bend his head backward: and thus to look up to Heaven, agreeth not only unto Men, but Asses; to omit Birds with long necks, which look not only upwards, but round about at pleasure. And therefore Men of this opinion understood not Plato when he said that Man doth Sursum aspicere; for thereby was not meant to gape, or look upward with the Eye, but to have his thoughts sublime; and not only to behold, but speculate their Nature, with the Eye of the understanding.
Now although Galen in this place makes instance but in one, yet are the other fishes, whose Eyes regard the Heavens, as Plane, and Cartilagineous Fishes; as Pectinals, or such as have their bones made laterally like a Comb; for when they apply themselves to sleep or rest upon the white side, their Eyes on the other side look upward toward Heaven. For Birds, they generally carry their heads Erectly like Man, and have advantage in their upper Eye-lid; and many that have long necks, and bear their heads somewhat backward, behold far more of the Heavens, and seem to look above the æquinoxial Circle. And so also in many Quadrupeds, although their progression be partly prone, yet is the sight of their Eye direct, not respecting the Earth but Heaven; and make an higher Arch of altitude then our own. The position of a Frog with his head above water exceedeth these; for therein he seems to behold a large part of the Heavens, and the acies of his Eye to ascend as high as the Tropick; but he that hath beheld the posture of a Bittor, will not deny that it beholds almost the very Zenith. Point of heaven over our heads.