Is Science Morally Neutral? The Curious Case of Fritz Haber

Is Science Morally Neutral? The Curious Case of Fritz Haber

Did you realize that one-third of the nitrogen atoms in your body did not come from nature? That the food that we eat contains amino acids, that nitrogen originally came from fertilizer, and most of that fertilizer, almost all, came from chemical factories? They, in turn, extract that nitrogen from the atmosphere using a process called the Haber Process – so the fact that we and billions of other people are not starving to death is a direct result of the invention of the Haber Process.

So who was Fritz Haber? Fritz Haber was a German chemist. He was born in the kingdom of Prussia before Prussia became part of Germany. He was born to a prominent Jewish family, but attended schools that were of mixed religious backgrounds, both Jews and Catholics and Protestants. He was conscripted and served in the military – as was traditional, he served his year of military service. 

In 1894, he converted to Lutheranism, and whether he did that out of personal convictions or to advance his career is not clear. But throughout his life, he identified himself as more German than Jewish. So he identified very much with Germany. And in 1909, he completed work which began with studies of the physical chemistry of gases, with the discovery of the Haber process, which I will talk about. He also developed the Born-Haber reaction cycle, which is used for understanding a variety of theoretical and practical and chemical knowledge, which led him to become, probably, the premier chemist in Germany from about 1910 to about 1930, and his laboratory, the Kaiser Wilheim Institute for Physical Chemistry, to be the greatest physical chemistry laboratory in the world.

He was instrumental in helping lure Albert Einstein to take an academic position in Germany. And he received the Nobel Prize in Chemistry in 1918 for his development of the Haber Process.

So why is nitrogen so important? Well, there’s a problem with nitrogen. 70% of the air is nitrogen. And nitrogen is essential for what? Amino acids that make up protein. That’s part of us. So the graphic I have on the right shows the natural processes for the atmosphere for the nitrogen fixing bacteria that exists in the rhizomes of some plants that take the nitrogen and turn it into compounds of nitrates and nitrates and ammonia.

But to do that is a very difficult process. It requires a lot of energy to break the double bond of nitrogens. So microbiota have to work very, very slowly. And if you want the fertilized crops, you have to have nitrogen to grow. You need to add fertilizer. And until early 1900’s, really the only source of fertilizer was nitrate oxide, essentially fossilized bird poop. And so that was the agricultural view [before Haber].

So along came Fritz Haber. Haber used the principles of entropy and energy that were first established by Chatelier in 1884 to determine that there should be a way to take hydrogen and nitrogen, and get them to combine to form ammonium, as the base process for filling fertilizer. He studied for several years and eventually discovered that the rare metal osmium should have been a good catalyst, and was able to catalyze the reaction. And in his tabletop laboratory, he was able to, drop by drop, turn air into ammonia, about 125 grams a day. That process was then taken over by Carl Bosch at the BASF, and they scaled it up enormously, so that instead of just sitting there and drip by drip, they’re able to make tons of it. And those tons were able to be turned into useful chemicals for the world and that process, the Haber process, the Haber-Bosch process, remains fundamental to the chemical world today. 

In 2018, 230 million tons, metric tons, of ammonia were produced that year. That’s a lot of fertilizer. The production of fertilizer consumes about 3-5% of the world’s total natural gas output, because natural gas is used as the feedstock for the nitrogen, and to produce the heat needed for the process. This is how the world avoids starving – is from the Haber process. And there’s a picture on the right of that chemical plant in Oppau, which was the first large scale producer.

Nitrates and nitrogen are for more than just fertilizer. All the explosives that we know we use today, all the common ones at least, also use nitrogen, mostly in the form of nitrates. And the German chemists, by the time that Haber’s process had been industrialized, had methods for taking the ammonia, turning it into nitrates, and turning those nitrates into explosives like nitroglycerin, dynamite, TNT, and also very much into ammonium nitrate, which is the primary fertilizer which is still used in the world today. If you have enough ammonium nitrate in any one place and it gets dry, it can explode on its own. The most common explosive used in the world today, ANFO, is ammonium nitrate and fuel oil.

It’s also dangerous to store large amounts of it. In 1921 – remember that picture I showed you just before, of the Oppau chemical plant? It blew up, almost 101 years ago today. 4,500 metric tons detonated. It killed about 600 people in the worst industrial disaster ever in Europe. For those of you who keep track of current events, there was a ship docked in Beirut a few years ago filled with ammonium nitrate. It blew up and killed several hundred people in Beirut. It was a tremendous – this is dangerous stuff. 

Haber was motivated not just by the need Germany had for fertilizer, but also the need Germany had for explosives. And Haber’s process is what kept Germany’s guns firing during World War I, and made sure that Germany – who couldn’t get the nitrates – they were embargoed by the British – couldn’t get the nitrates, could still continue to manufacture explosives. Just to give you an idea of the scale of the amount of explosives that were used during the First World War, Great Britain alone fired over 100 million artillery shells. 

So who was Fritz Haber? Well, he was more than just the developer of this chemical process. He was also the father of chemical warfare. He was an enthusiastic proponent of Germany’s entry into World War I; he was one of the signatories of the Manifesto of the Ninety-Three, and he actively recruited physicists and chemists to work on the war effort. He basically rededicated the Kaiser Wilhelm Institute to war work during the time that Germany was at war. 

And a key portion of that was the development of poison gas. Prior to the war, the chemists in Germany had developed hundreds upon hundreds of new chemicals for dyes and for perfumes and for industrial use. Under Haber’s direction, the chemists went back and looked to find out what was toxic, what was the most toxic, and how could it be used.

He developed the Haber equation, which was used to determine how much of a given poison gas would need to be delivered into a given area to achieve a given level of the balance. Germany was very grateful to him, the Kaiser himself promoted Haber into an Officer, which was not possible while he was serving earlier. And even after the war, Haber was still involved in the development of chemical agents, although under the cover of developing fumigants and other insecticides. And Haber’s central statement: “During peacetime,” he said, “a scientist belongs to the world, but during wartime, he belongs to his country.” 

So how did we get into this situation with chemical warfare? Because it appears to be prohibited by the Hague Conventions, to which Germany was a signator. Well, the process was a slow one. The French and the Germans both had begun to use tear gas. And other chemists, notably the Nobel chemist Walther Nernst, thought that saturating the trenches with poison gas would be a way to get a quick end to the war. And so I have a quote here from Nobel Prize physicist Otto Hahn, who was accorded by Haber to do war work, and he says:

“When I objected that this was a mode of warfare violating the Hague conventions, Haber said that the French had already started, although to not too much effect, by using rifle ammunition built with gas. Besides, this was a way of saving countless lives that meant that the war could be brought to an end sooner.”

So there was this idea that chemical warfare would end the war. By the way, it turned out that after the war, Haber himself investigated the claims of the French using chemical warfare prior to Germany’s use of it. And what he determined was that what the soldiers were smelling and being asphyxiated by was the remains of the explosive that was being used in front shells. It was a low quality explosive, and they were they were smelling picric acid.

So at that point, Germany committed to chemical warfare, with Haber leading the charge. The first use was at the Second Battle of Ypres, and on the evening of the 22nd of April to May 1919, Haber was at the front with several other future Nobel Prize winners, with 6,000 canisters of chlorine gas (chlorine gas is a liquid at about 30 degrees) and specially trained combat engineers, who Haber had led the training for. And they released 168 tons of chlorine gas, which was blown by the wind into the trenches of the allies. 5,000 men died directly as a result. There were another 10,000 allies [who suffered serious casualties]. But this success was not followed up. The German high command thought this was an experiment, and they weren’t prepared for a success. Within a week, the breach in the allied lines had been sealed, and the end result had been a lot of death and a lot of agony, but no real motion in the war. 

I have here a description of what it was like to suffer that first chlorine gas attack:

“…dropping with breasts heaving and agony and the slow poison of suffocation mantling their dark faces. Hundreds of them fell and died; others lay helpless, froth upon their agonized lips, and their wracked bodies powerfully sick, with tearing nausea at short intervals. They too would die later – a slow and lingering death of agony unspeakable.”

Germany continued to develop other chemical weapons – the list is very long. The most deadly of those weapons was phosgene carbonyl chloride, which was responsible for about 85,000 deaths in total during the First World War. About 100,000 of the 6 million deaths in the war were caused directly by poison gas. Perhaps the gas that caused people most pause was the use of mustard gas. This was a blistering agent which blinded people and left them with horrible blisters and left them horribly maimed, even if it didn’t kill them, and would linger on the battlefield for months after the gas had been fired. Haber rationalized the use of chemicals in the following quotation. He said:

“The disapproval that the knight had for the man with the firearm is repeated in the soldier who shoots with steel bullets towards the man who confronts him with chemical weapons. […] The gas weapons are not at all more cruel than the flying iron pieces; on the contrary, the fraction of fatal gas diseases is comparatively smaller, the mutilations are missing.”

While Haber is certainly true that men were horribly maimed and mutilated by the artillery, which was the primary killer of people during the First World War, plenty of people were maimed by gas attacks as well. 

So who was Fritz Haber? After the war, he was still a German patriot. Germany had crushing war remunerations to pay, and he looked to provide his physical chemistry to extracting gold from seawater. There had been an estimate that gold was of enough quantity in seawater that it could be probably extracted and used to take pay its war debt. He spent much of the 1920’s doing that, in addition to being the head of the Kaiser Wilhelm Institute, the President of the German Chemical Society, and a variety of honorary posts. 

So he led Germany’s work through the 1920s, he watched with increasing alarm the growth of the Nazi Party, even though he himself was immune from any of the formal edicts because he had served in the military at the front, and because he had converted from Judaism, nonetheless, he felt a fellow feeling for his Jewish compatriots. So in 1933, the Nazis promulgated a law, the Law for the Restoration of the Professional Civil Service, which required all civil servant servants who were of Jewish parentage to be fired from their positions unless they had actually served on the front during the war. Haber was immune, but he refused – he resigned his position and he left Germany forever. Before he resigned, he did everything he could to help find work for his Jewish employees. 

He went to Basel, Switzerland and eventually went for several months to England – at the invitation of some of the generals and military men who had been his former enemies. He worked in Manchester for a while, and then was invited by Chaim Weizmann to take up the directorship of the institute in Rehovot in Mandatory Palestine that we know today as the Weizmann Institute for Science. He was on his way there, in Switzerland, when he died in 1934. 

So he was a German patriot, he was the founder of fertilizer that enables us to eat our meals today, and he was also the father of chemical warfare. We’re left with the question: is science morally neutral? The Haber process could be used to make fertilizer to feed the world, or it can be used to make explosives to kill people. The poisons that Haber developed – many of them have peaceful uses today. A lot of the basis for modern insecticides came from the work that Haber was doing while he was researching poison gases. Scientists, I think, throughout the world recognized that there may be an enormous moral cost. And the question is: are we working for the betterment of humanity, or are we working for our own self-interest?

So there are a whole bunch of topics next slide that I didn’t talk about here when trying to present a brief of Haber and his very mixed legacy. And one of the people who I mentioned earlier was Chaim Weizmann. For those of you who aren’t familiar with that name, Chaim Weizmann was the first president of Israel. But before he was the first president of Israel, he was a PhD chemist. And he had determined that England was a key place that he should be. He was working ostensibly to try to discover synthetic rubber in England just prior to the war. What he discovered was something that came to be known as Bacillus Weizmannia, a bacterium that could be used to produce acetone. Acetone is a critical ingredient for cordite, which is the material used to fire artillery shells, and which the Munitions Ministry of England had a desperate need for. Lloyd George, who later became Prime Minister, was the head of the Ministry at the time, and Weizmann was one of the key figures who kept England’s guns firing during the war. So there is some evidence that the kindliness with which the British government viewed the Balfour Declaration is in part a reward to Weizmann for his work in keeping Britain’s guns firing during World War I. 

A second aside, which we could talk about more, is Haber’s wife, Clara Immerwahr. She was the first female chemist in Germany. She had a variety of chemical developments, married Haber, and then he would basically have her reduced to being a wife and mother. She was a pacifist, and she argued very strongly that Haber’s work as a chemist working on war work polluted the purity of science.

After one of these arguments, just before he was to go to the front to supervise another chemical warfare attack, Clara Immerwahr Haber committed suicide under suspicious circumstances. 

It’s an open question: would chemical weapons have been deployed if Haber had not embraced Walter Nernst’s initial idea? So there is still a mixed legacy. And as a final comment and sort of a lead-in, I think, into Rachel Petroff Kessler’s talk, artificial fertilizers are now a source of pollution. There are dead zones in the ocean which are dead because the fertilizer has caused microscopic plants to grow and keep the lower levels of the oceans dead. Is Haber part of that? And finally, if we do not use artificial fertilizers, then the yields of essential crops would be cut perhaps as much to one-eighth of what they are today. And I would ask as a ba’al tashchit question of whether one is wasting useful land: is it morally mandated to use fertilizers to fertilize your fields in order to feed the world?

Rachel Petroff Kessler: All right, Gary, thank you so much for your presentation. I did read a lot of articles about Fritz Haber before today, but I learned quite a lot more from your talk. And I’ll say iIm also really feeling the fact that I have not taken a chemistry class since middle school, and this really stretched my brain in some really great ways.

So our source sheets are going around, right, we’re going to see what connections we can draw between the life of Fritz Haber, as Gary so beautifully presented it to us, and this week’s Torah portion. I’m going to give a warning that in this and all future sessions of Scientists in Synagogues, we’re not going to be drawing perfectly straight lines, right. It’s not going to be like, “Oh, science has given us a moral quandary and Judaism gives us the answer,” right. That would be very nice; that is in fact not the way it’s going to work. Instead, what we’re going to be doing is reading texts from our tradition, with maybe different questions than we normally would, to see what sort of values we can pull out of them that we could apply to contemporary situations that the original authors of the texts could not have imagined, right? 

So it’s a process we’re going to be working on. It’s not always neat, sometimes it’s messy. So that’s just your warning: if you thought Gary was going to pose a question with science and I was going to answer it with Judaism, I am about to disappoint you, because that is not happening, right. So we’re not answering questions, we’re exploring together. I’m setting everyone’s expectations up for what’s going to happen.

So this week’s Torah portion is Parshat Shoftim, which covers a range of different things. We’re in the book of Deuteronomy, Moses giving his final talks to the Israelites before they enter the land of Israel, and in this Torah portion he covers the justice system that the Israelites should follow – if you were here last night, you might have heard Rabbi Plotkin talk about rules of witnesses for death penalty cases, and how a court system ought to operate.

Moses talked about future kings that the Israelites might have and limits on their possessions. He talked about how priests and Levites should live on donations from the people, and he explains laws of warfare that the Israelites are going to follow as they lay siege on cities that lie between them and their goal of occupying the land of Israel. And these are some of what we’re going to be focusing on today, right. So you have on your source sheet two verses from the Book of Deuteronomy:

“When in a war against a city, you have to besiege it a long time in order to capture it. You must not destroy its trees, wielding the axe against them. You may eat of them, but you may not cut them down. Are trees of the field human to withdraw before you into the besieged city? Only trees that you know do not yield food may be destroyed. You may cut them down for constructing siege works against the city that is waging war on you until it has been reduced.” (Deuteronomy 20:19)

Just those two verses have, in our tradition, opened up a real wealth of thought and commentary. […] Wars are going to happen, right. This is sort of the mentality that’s being offered here. Not “maybe it might happen that someday you will be in conflict with other people.” No –  “this is something that is going to happen, and here are some regulations we’re going to put around how it plays out.” But we’re not going to try and pretend that, I guess, God’s miracles aside, there’s not a magic wand that can be waved and poof, you get the land you want without there being any conflict along the way, right. In this vision, the war is a reality, it’s going to happen. 

Perhaps the trees are bystanders in some way. They’re not yours, they’re not in play, we might say, perhaps, as the war goes forward. And whatever happens, whether you win or not, the trees will be needed by whoever’s left standing at the end.


I pulled these two verses out, and there are other verses that talk about what you can and can’t do with the human victims of a siege. But I think you’re exactly right to raise the question of, “this is an awful lot of care you were devoting to not-people”, right – the trees compared, as they might be, two humans in these verses. But maybe we’d be best served if we turned our attention to other victims of the process, right So it’s an interesting thing that brings up for us the priorities that we notice in these verses.


We see in our modern day the ripple effects that come from being careless with the natural world around us, and that we don’t always fully appreciate the consequences of our actions. It’s easy to think, “Oh, look at me, all the things I can do and learn and I can control the world around me.” We, people in general, we really like to be in control of things, and the world reminds us that in fact there are lots of ways in which we are not in control. And we are not always aware of the consequences of our actions, and that the trees right play a critical space, right, in this sort of relationship. We have the world. It’s not all about us, that taking down the trees it doesn’t just have a negative impact on us, but on the animals, on the grasses, right, on the whole cycle of the natural world.

“For you will again be in need of these trees, to eat of their fruit after the war is over, and you have captured the city in question,” right. This is exactly what Alex said to us. You’re going to move into that city, and wouldn’t it be nice if you had some trees there that were there to give you fruits? Rashbam understands this mitzvah, this commandment, not to destroy the fruit tree as being really pragmatic and really self-focused on self-interest. It is for the long term benefit of the Israelites not to cut down the fruit trees, because once they move into these cities after the war is over they’re going to want them and need them, right. This is sort of his read.

Here’s another from Rashbam – we’re continuing on the sense of pragmatism. ‘The meaning of the verse “Only those trees,” right – “Only those trees that you know do not yield food.” That’s what he’s drashing on for us, that’s what he’s pulling out. “Only those trees,” he says, means the trees that can be used by man to hide behind and therefore interfere with your pursuit of war. “These you may cut down; they are generally the trees that are very close to the outer perimeter of the city under siege, that serve as hideouts for the enemy and represent a potential danger to your soldiers, in addition to giving shelter to enemy soldiers seeking to flee.”

Again, we see he has focused on the pragmatism of war, right. It would be great to save all the trees, but some of them, actually, if you leave them standing, they might be dangerous for you. They’re going to provide cover for the enemy, they’re going to be a place where you can be attacked from or where people could sneak away. And that in fact, those it’s better to cut down, because leaving them standing is going to get in the way of your goal of conquering the city, right. It’s going to interfere with your military pursuits.


And f we think back to Fritz Haber, he said, “Well, maybe this is distasteful, this chemical warfare, but you know what, it’s just going to get the job done and then we won’t be fighting anymore.” It turned out that it didn’t work out that way, but maybe that’s a line of thinking that you can walk down [that] could lead you to maybe some problematic places.

That’s powerful, right, this idea that you just are going to do whatever it takes to get it done. First of all it, doesn’t always end up working the way we think. And then it has consequences, again, right, to ripple out beyond what we might be thinking about in the moment. 

What I see here that is really beautifully, I think, played out, is when we have a real sense of “us and them” – it makes certain choices possible that maybe we don’t [normally] have. Maybe when it comes to trees and the environment, it’s easy to think of ourselves as all linked, and when we’re in a phase of war, we see some divisions and that might make go down paths to make different choices.


All right, we’re going to flip the page, turn to interpretation number three from Sforno, right. Look at this section: “Do not destroy the trees,” he says. “Don’t destroy the trees merely in order to practice wielding an axe. Destruction must not be wanted, it is justified only if it serves to harm the enemy residing within the city.” There’s still some pragmatism here. Yes, you’re in a war, you’re going to need to destroy some things and you’re going to need to do things that harm your enemy party. But don’t light bonfires just for fun, don’t knock down trees just to get practice wielding your axe. I love that that’s his example. Be sort of purposeful in the destructive choices that are necessary to make but don’t go beyond that, right. 

And I brought for us a Talmudic text, just because I think this is sort of an interesting way to see the way the rabbis expand on things in the Torah. We get this commandment here: “do not destroy these specific kinds of trees” gets expanded upon. Two that Gary referenced before also, right, this notion of “don’t destroy.” 

And you see the example they have here is of one who is wasteful with the oil in their lamp. Rav Zutra says, “he who covers an oil lamp or who uncovers a kerosene lamp for no purpose violates the prohibition ‘do not destroy,’” since by doing so, the fuel burns more quickly. That could take us in a whole other science aside about the lamps and fuel of ancient Israelites. But we see that this sort of becomes a broader principle in Jewish life. “Don’t be destructive thoughtlessly or for no purpose,” right. “Be purposeful in your use of your resources and the world around you.”

And we get another [from] Sforno   – it’s fascinating, right: “Are trees of the field people to withdraw before you?” It serves in the original verses as a rhetorical question. Trees are not like people, right, that’s what it means in the verses. But the rabbis ask, “Why would such a comparison occur?” It might be because there are some ways that trees are like people, and that therefore we sort of get played out in this way. 

So here’s what Sforno says: “Is a tree of the field equivalent to a human being, capable of defending itself and therefore posing a danger to you?” Of course not. “Neither is it able to surrender on account of the siege. Seeing that this is so, even though part of its timber could serve as a rampart for helping you to mount an attack against the city itself, since this will not be achieved directly by cutting down these trees, it is not proper for you to destroy such trees as opposed to your being permitted to kill human beings in that city opposing you and endangering you.”

Here we see the trees – they might be useful, they might not be. Nevertheless, right, it’s not proper to cut them down, because they do not pose the same threat to you that humans do. Here we again see the same sort of, like, “How do we feel about the protections that are placed around trees?” and maybe less care that’s put around the humans that are on opposite sides of the line.


So, Rav Sherira Gaon: “Our sages were not doctors, and said what they did based on experience with the diseases of their time, right.” Obviously, this is writing in a piece about medical care, but I think we can extrapolate to other scientific areas. “Therefore, there is no commandment to listen to the sages regarding medical advice, because they only spoke from their opinion based on what they saw in their day.” The Talmud is full of cures and things you might do for different ailments, and I don’t recommend any of their advice, but I’m wondering, if anyone wants to hazard a guess, as to when Rav Sherira Gaon was writing?

Rav Sherira Gaon was the gaon, he was the head of the yeshiva, of Pumbedita. He was born around 900 CE, right, only a few hundred years after, in some cases less [than that], the stages of the Talmud that he’s referring to. And already in his time, he saw enough advancement in medical care that he said, “Look, there are a lot of things that we’re going to follow the sages on, but this one, this is not one of them.” And I think it’s an interesting thing to think about in terms of the orientation that Jewish tradition has toward bringing evolving scientific understanding to our texts and our Jewish lives, right, and trying to sort of understand that there are some things, some values, that stick with us, and some understandings of the world that continue to evolve and change, right. So it’s sort of an interesting mindset that we’ll bring to all of our Scientists in Synagogues studies. 

And we’re not going to look at the very last text today, although if you want to read it on your own, you can. Instead we’re going to close, and then we can open up for more conversation and questions. We’re going to close with text #5, it comes from Kohelet Rabbah, right – it’s a book of Midrash on the book of Kohelet on Ecclesiastes:

“At the time that the Holy One created the first man, He introduced him to every tree in the Garden of Eden, and said to him, ‘See how wonderful and pleasant these trees are? And all of this I have created for you. Therefore, take great care that you do not damage and destroy my world, for if you do, there is no one else to put right what you have destroyed.’”

Oh dear. This is a writing from a long, long time ago, understanding that this world – particularly, we might say, this natural world – was a great gift that was given to us, but there’s no magic fixer-upper that’s going to come and reset us back to the beauty that we started with. That we have this responsibility, as we move through the world, to be thoughtful about the impact that we’re having on the world around us. […] We did things that were incredibly beneficial to our world, we did some things that were tremendously destructive. Maybe other people would have done them anyway, we don’t know. How do we weigh those things?

(This post is part of Sinai and Synapses’ project Scientists in Synagogues, a grass-roots program to offer Jews opportunities to explore the most interesting and pressing questions surrounding Judaism and science. This “Shabbat Lunch and Learn” on September 3 was the first event in Temple Isaiah’s Scientists in Synagogues series, “New Wars, Old Questions: Military Technology and Jewish Teachings in the 21st Century.” Gary Heiligman, PhD is a systems engineer, software engineer, and physicist, specializing in spacecraft, missile systems, spaceborne instruments, and observatories. He received his PhD from Princeton University and works at the Johns Hopkins University Applied Physics Laboratory).


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