Morris Ayin is dead, and kashrut will never be the same.

Morris, you see, was a big influence on me when I was a young boy. He often determined what was proper and what was not. When I was 5, for example, my father refused to allow us to put pareve margarine on the table during a meat meal “because of Morris Ayin.” I did not know Morris myself, but I was impressed that he commanded such authority.

Near the end of fourth grade, during a warp speed exploration of the Babylonian Talmud tractate Bava Metzia (fourth-graders do not often go in for the kind of hot and heavy debating that slows progress of Talmud study to a delightful crawl), I discovered the truth about Morris. He was not a person, at all, but a principle of Jewish law, “moris ayin” (marit ayin, in today’s modern pronunciation, or marit ha-ayin), which loosely means “for the sake of appearances,” or more pointedly “the appearance of transgression.”

The issue in that case was one that normally would cause a fourth-grader’s eyes to glaze over. A person had prematurely designated certain grains as a Temple offering, and then set a cow to the task of husking the grain by trampling all over it. The problem is Deuteronomy 25:4, which says: “You shall not muzzle the ox when it treads out the grain.” That would be fine if the grain belonged to the person whose cow was doing the trampling, but once the grain was designated for the Temple, it belonged to the Temple, so the man could not let his cow eat any of it. Muzzling the cow would seem to be the only solution, but that violates Torah law. (For how this problem was resolved, see BT Bava Metzia 89b-90a.)

What lit up my eyes was not the image of a cow stomping on grain. That image was way beyond the capacity of a fourth-grader on the Lower East Side, who never saw a cow or unhusked grain up close and personal. My eyes lit up because I finally understood why we could not put pareve margarine on a meat table: We did not want to give anyone walking by our fifth-floor window the wrong idea — that we were mixing meat with “milk.”

Considering that anyone walking by our window was more likely to give us the wrong idea, I asked my father about this seeming perplexity. He gave me the definitive answer for everything that did not make sense: “Azoy shteyt ess geshriben” (“that is the way it is written”).

I learned several years later that in this instance at least, it was the correct response. In BT Shabbat 64b and several other places in the Talmud we read: “Rav Yehudah said in Rav’s name: In every instance in which the Sages prohibited [something] for marit ha’ayin, [the thing] is forbidden even in the inner rooms,” meaning it was prohibited even if no outsider was likely to see it.

(To be sure, not everyone agreed with this ruling. See the debate between the schools of Shammai and Hillel in BT Beitzah 9a-b, where the issues involved drying wet clothes in the sun and moving a ladder between one bird shelter and another on a festival.)

Perhaps the most relevant examples of the Marit Ayin principle are to be found in BT Avodah Zarah 12a. Three cases are presented, all involving situations in which someone would have to bend down in front of an idol. In the first case, the person suddenly got a splinter in his foot and had to remove it. In the second, the person dropped some loose change. In the third case, a man desperately in need of some water finds a spring of fresh water immediately in front of the idol. In all three cases, bending down was prohibited because of marit ayin — someone observing from afar could conclude erroneously that the man was bowing down to the idol.

If a person dying of thirst may not bend down before an idol to drink from a pool of refreshingly fresh water because doing so might give others the wrong impression, how much more so should it be impermissible to have a beef taco smothered in “cheddar cheese,” or a helping of beef stroganoff, made with faux sour cream and served over “buttered” noodles. Why is macaroni and cheese an acceptable dish on Pesach, if the macaroni in question only looks and acts like the chametz variety?

An increasing number of faux chametz products hit the market every year at Pesach, products that would have sent old Morris Ayin into a tailspin. In this age of gluten-free, it even is possible to bake or buy “sandwich bread” and “pizza dough” and “blueberry muffins.”

All year-round, meanwhile, there are all kinds of faux cheese and dairy products for sale, all of them much improved over earlier attempts. In many cases, it may be difficult to tell the difference.

This is kashrut? In the case of the festival only three weeks away, this is Pesach?

Pesach is unique; the food restrictions and other distinctive features that accompany it are designed to emphasize that uniqueness. We wipe out that uniqueness when the only difference between yesterday and today is that the bagel is not as chewy and the Cheerios taste a bit funny. There is a growing library of wonderful Pesach cookbooks offering great recipes and meal ideas. There is no reason to resort to the output of the faux food factories. Is it asking too much to go without “pizza” or “bagel and a shmear” for eight days in order to observe one of the most momentous events in Jewish history?

As for lacing our meat dishes during the rest of the year with faux dairy products, we lose much there, too. There is a moral lesson behind “do not cook a baby goat in its mother’s milk,” and every time we keep meat and milk separate, we (in theory) are supposed to recall that lesson.

Milk, according to the Oxford Dictionary, is “an opaque white fluid…secreted by female mammals for the nourishment of their young.”

Milk represents life for newborn infants, animal or human.

Meat is the flesh of a dead animal. When the Torah says not to boil a young goat in its mother’s milk, what it means is, “Can we be so cruel as to kill an infant and then cook it in the very liquid meant to give it life?”

Is that a lesson to be lost? The Sages of Blessed Memory did not think so. When it became virtually impossible for the milk being used to cook baby goat’s meat to have come from its mother, they expanded the Torah’s rule to include all meat and milk rather than see the lesson disappear.

If only Morris Ayin still lived.