Our Gemara on Amud Beis draws a distinction between doubts that affect kashrus versus doubts that affect danger to health. When it comes to kashrus, we follow various legal formulae such as majority, chazakah and other principles. However, if we are unsure of an item’s toxicity, such as water left exposed which may have snake venom in it, we cannot rely on legalistic principles to ensure that it isn’t poisonous.

However, is it really that simple? If a person treats his religious principles and fear of God with due reverence, why would he be less concerned about something being unkosher than about being poisonous? If anything, the opposite is true because if one ingests poison, they die a single death, but if they commit a spiritual transgression, they are dying in the afterlife. In the words of Rabbi Yochanan Ben Zakkai on his deathbed (Berachos 28a):

“I cry in fear of heavenly judgment, as the judgment of the heavenly court is unlike the judgment of man. If they were leading me before a flesh and blood king whose life is temporal, who is here today and dead in the grave tomorrow; if he is angry with me, his anger is not eternal and, consequently, his punishment is not eternal; if he incarcerates me, his incarceration is not an eternal incarceration, as I might maintain my hope that I would ultimately be freed. If he kills me, his killing is not for eternity, as there is life after any death that he might decree. Moreover, I am able to appease him with words and even bribe him with money, and even so I would cry when standing before royal judgment. Now that they are leading me before the supreme King of Kings, the Holy One, Blessed be He, Who lives and endures forever and all time; if He is angry with me, His anger is eternal; if He incarcerates me, His incarceration is an eternal incarceration; and if He kills me, His killing is for eternity. I am unable to appease Him with words and bribe him with money.”

The Chasam Sofer explains that the key difference is what the Torah allows and forbids. Since the Torah itself permits substances that may be unkosher if they are nullified or subject to certain assumptions, in effect they become kosher. The same law that prohibits can also say it’s permitted. However, poison is poison and will not change due to legalisms.

On the surface, this makes sense. Halacha is part of a legal process but snake venom is part of the physical world. Yet this too is not so simple. The very same Chasam Sofer famously rules that the physical world is subject to Halacha. In a responsa (Shu”t Chasam Sofer, O.C. 14) he cites numerous examples of how a rabbinic halachic decision of declaring the new month, seasons and leap years can even retroactively change physical characteristics such as physical maturity of humans and ripening of fruit. He also famously rules that medical matters for Jewish people cannot be determined by the anatomical and statistical studies of how gentiles are affected (Shu”t YD 175.) He considered Jewish people to be anatomically distinct due to the impact of eating only kosher versus non-kosher foods. To the Chasam Sofer, it seems that the Halacha dictates the reality, not the other way around.

Returning to his original comment on our Gemara, I think we can understand the Chasam Sofer with more nuance. He was not saying that reality is one thing and Halacha is just legalisms. Rather, Halacha is the reality for all things. It just so happens that the Halacha decrees the reality of kashrus on assumptions, and once the assumption states it is permitted then its reality changes and it becomes permitted. However, the Halacha does not make assumptions about health matters and therefore assumptions do not offer absolute protection from the venom that might be in the water, even if it is a 1/1000 chance.

This still begs the question of why. In other words, we can accept that for whatever reason it is the will of God to say that one can rely on legalisms to permit a piece of meat, and even if technically that piece of meat was not kosher it now is kosher because the law permits it. But why did God not make a world where you can use the same assumptions to protect us from physical dangers? Why does God allow more laxity when it comes to observance of His commands than when it comes to safety?

I think the answer is about obedience versus technical considerations of safety, and the appropriate state of mind for each. The main function of a commandment is to establish a connection between man and God by following the covenant. One does not keep Kosher for its own sake or because it is healthy, but rather because God commanded it. Therefore the emphasis is on obedience to the laws and rules, and so those same laws that forbid can also permit. (True, there is a concept that non-kosher foods engender an intrinsic spiritual clogging of the heart, see Shach YD 81:26; the overall idea is about faithfulness to God’s commandments and the legal aspect is stressed.)

However, when it comes to physical and personal safety, autonomy, judgment and self care are paramount. Therefore here the focus is on self protection and health maintenance which comes from agency and purpose. This should not be trusted via legalisms or assumptions but rather via personal investment to safeguard the soul and body granted to us by God, which is tasked to live in the physical world and subject to its rules.