Spontaneous generation of frogs and lice

Summary: Ibn Caspi, a Rishon, explains the workings of two of the plagues based on the scientific workings of spontaneous generation. This should be taken as additional evidence that Rishonim can be wrong in matters of science.

Post: I wish to preface this with an explanation of why I should care to establish that Rishonim can and do err in matters of science. It is not that I want to undermine the Rishonim and that I consider them morons, chas veShalom. Just the opposite. I consider them to be extremely smart and insightful people, who were well-versed in the science of their day, and who applied that mada knowledge towards understanding Torah. That as a result, they drew false conclusions is beside the point.

No. Chas veshalom. I don't consider the Rishonim to have been morons. The morons are the modern day individuals who, because of frumkeit, insist against all evidence that a Rishon could not be wrong; that if it seems the Rishon was wrong, the Rishon was really saying something deep and mystical; and that you, who think a Rishon can be wrong, are a kofer. The last part is most galling. It is this sort of moronic and ignorant "frum" attitude that I try to counter, and so repeated demonstrations of Rishonim, or Chazal, relying on contemporary science should be viewed only as an argument against present day ignorant folk.

Another reason for detailing instances in which Rishonim relied on contemporary science is to bolster the true idea that a great way to understand what a source (be it a Rishon, an Amora, or a Tanna) means is to see what sort of inputs he had, be it Aristotelean science of Sassanian law. This leads, IMHO, to more correct interpretations of sources -- and understanding Chazal (or a Rishon) correctly is more important, and grants Chazal more respect, than making Chazal (or a Rishon) correct by reinterpreting their words in a way they never intended.

This idea is independent of any one piece of evidence. But here is the one in play, from Ibn Caspi, assuming I understand him correctly. Roughly, in Vaera, as a result of makkat dam, the river became disgusting:

יח  וְהַדָּגָה אֲשֶׁר-בַּיְאֹר תָּמוּת, וּבָאַשׁ הַיְאֹר; וְנִלְאוּ מִצְרַיִם, לִשְׁתּוֹת מַיִם מִן-הַיְאֹר.  {ס}

18 And the fish that are in the river shall die, and the river shall become foul; and the Egyptians shall loathe to drink water from the river.' {S}

This immediately preceded tzefardea; and this works well, because the rotten river became material for the frogs. And when they piled up the frogs, the land became foul:

י  וַיִּצְבְּרוּ אֹתָם, חֳמָרִם חֳמָרִם; וַתִּבְאַשׁ, הָאָרֶץ.

10 And they gathered them together in heaps; and the land stank.

And this was as material for the spontaneous generation of the kinnim, for as is known {in Ibn Caspi's contemporary science}, kinnim are born from moisture plus the addition of heat. {Indeed, hot and moist conditions might be conducive to various species multiplying; though this would not be the chomer for its coming into being via spontaneous generation. From his comments on parshat Bo, he says as follows: