An example of metaphor in historical science writing,
"We cannot know anything of nature but by an analysis of it to its true initial causes: and till we know the first springs of natural motions, we are still but ignorants. These are the alphabet of science, and nature cannot be read without them. Now who dares pretend to have seen the prime motive causes, or to have had a view of nature, while she lay in her simple originals? We know nothing but effects, and those but by our senses. Nor can we judge of their causes, but by proportion to palpable causalities, conceiving them like those within the sensible horizon. Now 'tis no doubt with the considerate, but that the rudiments of nature are very unlike the grosser appearances. Thus in things obvious, there's but little resemblance between the mucous sperm, and the completeed animal. The egg is not like the oviparous production: nor the corrupted muck like the creature that creeps from it. There's but little similitude betwixt a terreous humidity, and plantal germinations; nor do vegetable derivations ordinarily resemble their simple seminalities. So then, since there's so much dissimilitude between cause and effect in the more palpable phenomena, we can expect no less between them, and their invisible efficients. Now had our senses never presented us with those obvious seminal principles of apparent generations, we should never have suspected that a plant or animal could have proceeded from such unlikely materials: much less, can we conceive or determine the uncompounded initials of natural productions, in the total silence of our senses."
Joseph Glanvill (1661) Scepsis Scientifica; or, The Vanity of Dogmatizing
Glanvill argues for the investigation of the hidden causes/mechanisms of nature (see also: nature like a watch has hidden workings). Initial causes as 'first springs' is a metaphor that reflects a common mechanical worldview in early science, and Galnvill compares these to an alphabet for reading nature (an extended metaphor).
Nature is personified in the reference to her simple 'originals' (an archaic term for source or cause – Merriam-Webser Dictionary).
Read about personification in science texts
Read examples of personifying nature
Read other examples of personification
Creatures creeping (nice alliteration) from the corrupted muck seems to refer to the longstanding idea that some simple organisms such as worms and flies did not arise from parents of the same kinds but from decaying material, that is, by spontaneous generation.
