Lev. 11:20-3 All fowls that creep, going upon all four, shall be an abomination unto you. Yet these may ye eat of every flying creeping thing that goeth upon all four, which have legs above their feet, to leap withal upon the earth; even these of them ye may eat; the locust after his kind, and the bald locust after his kind, and the beetle after his kind, and the grasshopper after his kind. But all other flying creeping things, which have four feet, shall be an abomination unto you.
Is this an error -- since insects have six feet, not four, and since "fowl" have two feet, not four?
The reference to "fowl" is thought by some Skeptics to refer to birds, but the word used here is 'owph, which merely means a creature with wings -- it is the same word used in verse 21 (flying). The reference in both cases is to insects.
Now we might call this a poetic phrase (i.e., "crawling around on all fours"), and this is partially right. But there is an even better - and more correct - answer.
Quite simply, the big back legs on the locust, etc. were not counted as "legs" in the same sense as the other legs. Let's use an illustration from George Orwell's Animal Farm.
In this story, Snowball the pig invented the slogan, "Four legs good, two legs bad" so as to exclude humans from Animal Farm society. The geese and other fowl objected, because they had only two legs. Snowball explained (more clearly in the book than in the movie) that in animal terms, the birds' wings counted as legs because they were limbs of propulsion, not manipulation, as a human's arms and hands were.
Now note the differentiation in Leviticus above -- referring to "legs above the feet" for leaping. The "feet" are being differentiated from the "legs above the feet" because of their difference in function. They are legs, but in a different sense than the "four" legs which are just called "feet." We are being told of two types of legs: The "on all four" legs (which are nowhere called legs; they are only called "feet" [v. 23]), and the "leaping legs."
It is clear that the Hebrews regarded the two large, hopping hindlimbs of the locust and the other insects of the same type, which are the only types of insects mentioned here (we now translate "beetle" as "cricket"), as something different than the other four limbs - perhaps because they were used primarily for vertical propulsion, whereas the other limbs were for scurrying around.
Shifts of terminology like this happen even today; there have been propsoals to redefine "planet" and there has been a similar issue with the "legs" of the octopus.
Unacceptable? The alternative is to say that the Hebrews - who ate these things raw - didn't see that these bugs had six legs.
Objection: Such insects are sometimes hard to find, and some cannot be found for up to decades at a time. So it's possible they did make such a mistake.
Not all such insects disappeared entirely for any length of time, and the author of Leviticus, by virtue of his literacy, clearly within the context of the ancient world had to be someone with a few years under his belt. There is no way it can be claimed that he happened to live in a timeframe when there were never and insects of this type around, or no one who knew better.
I did a little private survey and found out that a few people, even intelligent ones, did not know that insects had six legs.
All this really shows is that people aren't getting a decent science education...not that this is relevant anyway, since it is doubtful that any of them ate insects as part of their regular diet and had them constantly in their face as the Hebrews did.
What other "winged insects with four feet" (11:23) could there be?
The last pair of legs of many winged insects are specially designed for jumping or "lifting off" and therefore serve a differing function than the other four legs. With millions of species of insects in the world it seems rather presumptuous to try to select just a few and claim that these make a hash of Lev. 11:23. But let's just take one as an example.
Check the anatomy of the honeybee. Any picture shows clearly enough that the rear legs present an entirely different orientation than the other four. More technically, they serve a different function and have a different structure, as a source (now offline) said:
[T]he hind legs differ from the other legs in their larger size and broad flattened form. These legs differ in size in the queen, worker & drone. It is only the worker that collects pollen and places it in the pollen baskets on these hind legs. The legs have long curved hairs. The space enclosed by these hairs is called the pollen basket. The worker bees carry pollen to the hive storing in these conclave shaped hind legs. The pollen is collected from the body by the front and middle legs and deposited on the large flat brushes on the inner surfaces of the hind legs. Each of which is covered by 10 transverse rows of stiff spines projecting backwards.
Although these legs are used to walk (even as the grasshopper's can be and are), in function and appearance they are clearly, vastly different. The Hebrews were just as able (and by extension of the same scheme used with grasshoppers, katydids, etc) to regard the back legs of other types of flying insects as being of a different order, of being something different, so that only the first four were called plain old "feet" as only the first four on the hoppers, etc. were called feet, while the others were given a differing name such as "legs above their feet".