Oh boy, it's super complicated. Be ready for a long read.
So, the first question is, how do I know that I am supposed to eat? God provided me with hunger. God provided me with relief after I eat. God provided me with gratitude for recieving food. All of those thing justify consumption. God provided hunger.
Next step is to figure out what God provided for me to eat. I'm going to be looking for things which are, for lack of better words, "low hanging fruit". This is easy to imagine in terms of plants. An apple hanging from a low branch among many apples, so many that if I take one no one will miss it, and the tree is actively blooming. God certainly has provided this for food. In Judaism all plants are perfectly kosher ( proper ) for food. ( assuming it wasn't a branch that was grafted, which would be violating God's will / assuming that the plant was not cross-bred which violates God's will )
But, if I imagine myself as a primitve human, sooner or later, I'm going to see another animal ( similar to myself, maybe ) eating another animal. From this, I might consider, "Did God provide animals for me to eat as well?" The same mental question-answer will occur with insects too. "Did God provide those for me?"
So, if I were looking for signs of whether or not these moving things ( like me ) are provided, intended for me, I might consider.. first of all, is it a dangerous for me? Does it have sharp teeth and claws? Is it a natural predator. ( Those are prohibited ). Does it burrow into the ground? Maybe that means God is hiding it from me ( rabbit is prohibited, moles, etc.. ). The same logic is applied to all insects, worms, etc... those things burrow and hide themself from me. The same logic is applied to shellfish. God put them under the sea, made them look like rocks, and I have to work my little kosher rear end to get the good stuff out from it? Nope, those are out too.
So that leaves herding animals. Blunt teeth, hooves. Eats grass. Non-predators, not dangerous. They like to live where I might like to live. Near water sources in open spaces, etc... but this still doesn't tell me that they are provided for me to eat. But ... there's signs that they are being provided for some purpose other than just, I don't know, being there.
If I go back to the "low hanging fruit" idea and apply it to herding animals, something is going on there. The animals are kind of like low hanging fruit. The key aspect is the number, and that they are reproducing actively and have developed into a herd kind of like a bunch of grapes. This tells me that God is providing them for some purpose that maybe isn't being actualized, for lack of a better word. So I wonder what that purpose is.
If we start to analyze the signs that are described in the Torah for a kosher animal, there's something unique about them which seperates them from the others. But on first glance, these differences serve no real purpose for their surviving or thriving. ( Perhaps they do/did have a purpose, but as a primitive person, I wouldn't know that, I don't know anything about evolution or science ). These seemingly uneeded differences are confirming in my mind that these animals have a unique but hidden purpose for which they have been provided by God.
Something to consider.
In the story, in the beginning, only plants were granted as food, but all of humanity was instructed to, sheppard, for lack of a better word, the natural world. And, in th story of Cain and Abel, Abel brought the best of the flock. But they were not permitted to eat the animals yet. And God accepted Abel's offering, but declined Cains. According to the story, somehow, Abel figured out that animals could be offered and God accepted it, but didn't receive any... carnal reward for it.
So, I'm a primitive person, and I notice, that certain types of animals, respect me, and permit me to approach them, and are gentle, and might even follow me around if I carry a big sheppard's stick. And some animals, like horses for example, defintely don't do those things. Something about that lamb is telling me, "I want to do what you command". And when I care for them, and sheppard them they produce many offspring. Maybe those ofspring, the perfect ones, have a higher purpose. ( Kosher animals are selcted based on these criteria )
And it's feet are split, telling me it wants to be lifted up. And it chews its cud, it has multiple divided stomach cavities, telling me it refines the world, and it divides, and seperates which is reflecting a primitve version of consecration, selecting something for a higher purpose. I'm starting to feel confident that this little beast was provided, brought down, for the specific purpose of being lifted back up.
So, I build an altar and I discover that there is a painless way to slaughter it. Perhaps with obsidian (arguably the keenest edge, even by today's standards, just scattered all over the place if a peson knows where to look ) or some other thing which again I discover has been provided by God for this purpose. Now I'm feeling like all sources are pointing towards, it's OK to kill this little beast. I have been provided the tools, the knowledge, the animal seems to have been designed for this specific purpose, it's like low hanging fruit. So I kill it offer it and I eat it and see what happens.
The same sort of logic is applied to derive which parts of the animal belong on the fire, it's rather "magical" what happens when fat is placed on a fire, when I kill it, the blood does not seem to be provided for me. But this beast has long powerful legs, but it never seems to run away. Maybe that part is for me? So now I've decided which parts of the animal have been provided by God for me. And the aroma. Oh my goodness. That's magical. The smoke!!!! Wow! I notice dead things and rotten things don't smell right. But this is glorious, for lack of a better word. I'm feeling really really good that God has set the table, so to speak, for all this to occur.
Meat in the primitve diet maybe helped brain development? I'm not sure, I think diversity of food sources helped brain development at the least. Meat can be preserved using primitive technology. Killing animals helps sustain me through the winter when plants are not blooming. If my brain is developing, and I am develping more abstract thoughts, and this is correlating to a deeper appreciation of the natural world, and simultaneously, I'm starting to make abstract realizations about an underying truth and cooperative realtionship that exists among all things. And this is leading to a god-concept, which is telling me, **all of this has been provided for me. All of it has been provided to approach God, to understand God, to have a relationship with something far bigger than anything I can ever know.**
But part of that includes ID'ing certain animals are being provided for a specific hidden purpose. Relaizing that the obsidian wasn't just randomly provided in seemingly unlimited quantity. Have you ever seen an obsidian flow? It's like another planet. And there is so much razor sharp obsidian, it's other-worldly. All of those primitve knives, were delivered by God, provided for a purpose. If not, there wouldn't be massive piles and piles and piles of them, like the apples that fall from a tree if they are not eaten.
So, that's basically it. There's signs that indicate an animal is OK to eat, IF its the correct animal and IF its the right parts only, and IF it is slaughtered in a specific way, and IF the parts that belong to God are returnd to God, and the parts that have been provided to the earth go directly to the earth. And if all of those things happen in the right time and right place, a person can consume part of the animal and recieve a blessing from God confirming that all of that primitive logic produced a working model for how to live and operate in the crazy material world in harmony with God's will.
