Over the last little bit, conversation has been flying fast and furious between Rav Natan Slifkin, Rav Yosef Gavriel Bechhofer, and Thanbo's blog on the definition of death and the science Chazal used to make that determination. A lot of space has been used to discuss whether or not Chazal understood science as we do today and if their presumptions about how the human body works are still relevant in light of the development of anatomical and physiological knowledge in the last couple of centuries along with the development of cardiopulmonary resuscitation.
With all that's been said, and begging the forgiveness of these folks for my presumptious sticking of my nose into their discussion, I think an important point has been missed that must be mentioned.
The root gemara for discussing the definition of life is found in Yoma. As Rav Slifkin notes in his post (linked above), the case involved a person inside a building which then collapses on him. Even if it's on Shabbos we are obliged to go to his aid and begin removing the rubble to save his life. Should we find his head and discover that he is not breathing, we are to cease all rescue efforts immediately. He's dead and the permission we had to push aside Shabbos restrictions now ceases since there's no longer a life to be saved. Chazal's conclusion is that spontaneous respiration is the litmus test of life.
The problem with using this Gemara in a carte blanche fashion to prove either that Chazal did not know about modern science or that they might have changed their mind had they known about CPR is that it looks at the scenario much too superficially. It assumes, amongst other things, that respiratory failure is a monolithic condition that always occurs the same way and with the same consequences.
However, this is patently false and to understand the Gemara does not require one to pass judgement on the state of Chazal's medical and scientific knowledge. In fact, I'm surprised that people approach this gemara from such a position in the first place. Given that almost every rule Chazal bring comes with caveats and explanations, how can one think that this definition of respiratory cessation as death applies in all cases?
Let me start by giving some examples.
- A 15 year old healthy male drowns in a very cold river or lake. He is rescued almost immediately after going down and when pulled to shore is found not to be breathing.
- A 46 year old obese male with a history of high blood pressure and diabetes is walking down the street when he suddenly clutches his heart and drops to the ground unresponsive and not breath
- A 73 year old female with terminal cancer and six prior heart attacks suddenly flatlines after spending the last three hours in slowly worsening heart failure.
- A 52 year old driving a car is struck head-on by a Mac truck and is crushed to death.
In all four cases, the victim will have stopped breathing. However, the first patient will, with prompt assisted breathing and CPR along with rewarming, make a good recovery. The second patient will only have a shot at life if someone begins chest compressions and gets a defibrillator to him within a couple of minutes. The third is going to die no matter what is done because her body is worn out and wouldn't respond to resuscitation. The final case doesn't require any explanation.
In other words, cessation of respiration is usually attached to imminent death but not always. The context of the respiratory failure is paramount.
(By the way, Rav Slifkin makes a mistake in his assessment of CPR that is common amongst non-medical folk:
Now, for a while it has been known that even if respiration has ceased, it is often possible to restart it via cardiopulmonary resuscitation - CPR. It is therefore commonly stated that the Gemara was not referring to a person whose breathing has merely stopped, but rather to a person whose breathing has irreversibly stopped. Of course, Chazal did not know about CPR, but, it is claimed, their words did not rule it out.
This is wrong. CPR is not about restarting respiration. It's not even about restarting the heart. CPR is about transferring potential energy to the cardiac muscle so that when electricity is applied with the defibrillator there will be enough to provide kinetic energy to get the heart pumping again. That's all that CPR does. Therefore Chazal not knowing about CPR is irrelevant to the scenario in Yoma.)
Now let's look once more at the gemara's case. Imagine the time line - a person is in a building which then collapses. The rescuers must be assembled, they must begin to dig and they must make enough progress to find the guy under all the rubble. One thing I don't hear anyone commenting about is the time line. This is not something that takes a few seconds. How many minutes pass before the person's head is found - fifteen? Thirty? An hour?
We often think that the ancients didn't know about science but we are wrong to an extent. While they did not know about mechanisms such as the germ theory of disease or the role of the heart and brainstem in maintaining life they were able to observe phenomena in a very meticulous fashion, just as accurately as us. Their conclusions might have been different but if we concentrate on their observations we would soon see that they were sometimes quite right even if they didn't explain their findings the way modern scientists might.
Our case in Yoma is just such an instance. This is cleearly a case of death by trauma and I believe Chazal chose it to make a specific point. They could just have easily said "A person falls to the ground and stops responding" and used that as their case. Sudden cardiac arrest is as old as the race, after all, but they didn't. They chose death by trauma to tell us that when one finds a person buried in rubble for a while and he's not breathing, he's dead. Period. And in this case they were pretty much right. Death by trauma is generally instantaneous (unless it's due to a slow bleed or something like that) and Chazal knew it. Therefore they were confident in saying that if you find such a person not breathing they're dead and all you have to do is check their nose to confirm it. This makes perfect sense even in modern times given that the brain stem is the source of independent respiration and with its dissolution so goes everything else.
As a result, one cannot simply say "Chazal said that if a person stops breathing he's dead and if they'd known about modern science they'd have said differently". Chazal said, in this gemara, that if a building falls on your head and kills you, you're dead and we can't desecrate Shabbos to excavate you. What would they have said about sudden cardiac arrest? We don't know but surely given what we do know about those principles they would have encouraged us to use all available resources to determine if it is possible to save the person.
Therefore Chazal were not wrong in their description of death in Yoma but only through an understanding of the complexity of respiratory failure and the specific context of the case can we see that.