Science and Philosophy
   

"This may take me to another point, which is should a scientist think about philosophy, or not? It’s sort of the fashion today to discard philosophy, to say now we have science, we don’t need philosophy. I find this attitude very naïve for two reasons. One is historical. Just look back. Heisenberg would have never done quantum mechanics without being full of philosophy. Einstein would have never done relativity without having read all the philosophers and have a head full of philosophy. Galileo would never have done what he had done without having a head full of Plato. Newton thought of himself as a philosopher, and started by discussing this with Descartes, and had strong philosophical ideas.
"But even Maxwell, Boltzmann, I mean, all the major steps of science in the past were done by people who were very aware of methodological, fundamental, even metaphysical questions being posed. When Heisenberg does quantum mechanics, he is in a completely philosophical mind. He says in classical mechanics there’s something philosophically wrong, there’s not enough emphasis on empiricism. It is exactly this philosophical reading of him that allows him to construct this fantastically new physical theory, scientific theory, which is quantum mechanics.  
"The divorce between this strict dialogue between philosophers and scientists is very recent, and somehow it’s after the war, in the second half of the 20th century. It has worked because in the first half of the 20thcentury, people were so smart. Einstein and Heisenberg and Dirac and company put together relativity and quantum theory and did all the conceptual work. The physics of the second half of the century has been, in a sense, a physics of application of the great ideas of the people of the ’30s, of the Einsteins and the Heisenbergs.
"When you want to apply thes ideas, when you do atomic physics, you need less conceptual thinking. But now we are back to the basics, in a sense. When we do quantum gravity it’s not just application. I think that the scientists who say I don’t care about philosophy, it’s not true they don’t care about philosophy, because they have a philosophy. They are using a philosophy of science. They are applying a methodology. They have a head full of ideas about what is the philosophy they’re using; just they’re not aware of them, and they take them for granted, as if this was obvious and clear. When it’s far from obvious and clear. They are just taking a position without knowing that there are many other possibilities around that might work much better, and might be more interesting for them.
"I think there is narrow-mindedness, if I might say so, in many of my colleague scientists that don’t want to learn what is being said in the philosophy of science. There is also a narrow-mindedness in a lot of probably areas of philosophy and the humanities in which they don’t want to learn about science, which is even more narrow-minded. Somehow cultures reach, enlarge. I’m throwing down an open door if I say it here, but restricting our vision of reality today on just the core content of science or the core content of humanities is just being blind to the complexity of reality that we can grasp from a number of points of view, which talk to one another enormously, and which I believe can teach one another enormously." 
                                                                        -Carlo Rovelli
[edge.org/conversation/a-philosophy-of-physics]

Science and Philosophy

 

"This may take me to another point, which is should a scientist think about philosophy, or not? It’s sort of the fashion today to discard philosophy, to say now we have science, we don’t need philosophy. I find this attitude very naïve for two reasons. One is historical. Just look back. Heisenberg would have never done quantum mechanics without being full of philosophy. Einstein would have never done relativity without having read all the philosophers and have a head full of philosophy. Galileo would never have done what he had done without having a head full of Plato. Newton thought of himself as a philosopher, and started by discussing this with Descartes, and had strong philosophical ideas.

"But even Maxwell, Boltzmann, I mean, all the major steps of science in the past were done by people who were very aware of methodological, fundamental, even metaphysical questions being posed. When Heisenberg does quantum mechanics, he is in a completely philosophical mind. He says in classical mechanics there’s something philosophically wrong, there’s not enough emphasis on empiricism. It is exactly this philosophical reading of him that allows him to construct this fantastically new physical theory, scientific theory, which is quantum mechanics.  

"The divorce between this strict dialogue between philosophers and scientists is very recent, and somehow it’s after the war, in the second half of the 20th century. It has worked because in the first half of the 20thcentury, people were so smart. Einstein and Heisenberg and Dirac and company put together relativity and quantum theory and did all the conceptual work. The physics of the second half of the century has been, in a sense, a physics of application of the great ideas of the people of the ’30s, of the Einsteins and the Heisenbergs.

"When you want to apply thes ideas, when you do atomic physics, you need less conceptual thinking. But now we are back to the basics, in a sense. When we do quantum gravity it’s not just application. I think that the scientists who say I don’t care about philosophy, it’s not true they don’t care about philosophy, because they have a philosophy. They are using a philosophy of science. They are applying a methodology. They have a head full of ideas about what is the philosophy they’re using; just they’re not aware of them, and they take them for granted, as if this was obvious and clear. When it’s far from obvious and clear. They are just taking a position without knowing that there are many other possibilities around that might work much better, and might be more interesting for them.

"I think there is narrow-mindedness, if I might say so, in many of my colleague scientists that don’t want to learn what is being said in the philosophy of science. There is also a narrow-mindedness in a lot of probably areas of philosophy and the humanities in which they don’t want to learn about science, which is even more narrow-minded. Somehow cultures reach, enlarge. I’m throwing down an open door if I say it here, but restricting our vision of reality today on just the core content of science or the core content of humanities is just being blind to the complexity of reality that we can grasp from a number of points of view, which talk to one another enormously, and which I believe can teach one another enormously." 

                                                                        -Carlo Rovelli

[edge.org/conversation/a-philosophy-of-physics]

A rabbi, a priest, and a minister walk into a bar.
   
Despite sharing certain similar views related to science and mathematics, physicists in the modern age hold a wide range of differing views regarding religion. Einstein was a proponent of Spinoza’s god rather than a believer in a personal god. This didn’t prevent him from showing his displeasure with quantum mechanics, despite its acceptance by other physicists, by stating “God doesn’t play with dice.”
Max Planck in 1944 said, “All matter originates and exists only by virtue of a force which brings the particle of an atom to vibration and holds this most minute solar system of the atom together. We must assume behind this force the existence of a conscious and intelligent mind. This mind is the matrix of all matter.” This remark seems to indicate belief in some sort of God. Shortly before his death in 1947, however, he stated that although he had always been deeply religious, he did not believe in a personal God.

Heisenberg [in Physics and Beyond, 1971, pp. 85–86] recalls a conversation among a small group of young physicists at the 1927 Solvay Conference about Einstein and Planck’s views on religion. Wolfgang Pauli, Heisenberg and Dirac took part in it. Dirac’s contribution was a criticism of the political purpose of religion. Although known among his colleagues for his precise and taciturn nature [colleagues in Cambridge jokingly defined a unit of a dirac which was equal to one word per hour] he comes off here as quite loquacious. 

"I cannot understand why we idle discussing religion. If we are honest—and scientists have to be—we must admit that religion is a jumble of false assertions, with no basis in reality. The very idea of God is a product of the human imagination. It is quite understandable why primitive people, who were so much more exposed to the overpowering forces of nature than we are today, should have personified these forces in fear and trembling. But nowadays, when we understand so many natural processes, we have no need for such solutions. I can’t for the life of me see how the postulate of an Almighty God helps us in any way. What I do see is that this assumption leads to such unproductive questions as why God allows so much misery and injustice, the exploitation of the poor by the rich and all the other horrors He might have prevented. If religion is still being taught, it is by no means because its ideas still convince us, but simply because some of us want to keep the lower classes quiet. Quiet people are much easier to govern than clamorous and dissatisfied ones. They are also much easier to exploit. Religion is a kind of opium that allows a nation to lull itself into wishful dreams and so forget the injustices that are being perpetrated against the people. Hence the close alliance between those two great political forces, the State and the Church. Both need the illusion that a kindly God rewards—in heaven if not on earth—all those who have not risen up against injustice, who have done their duty quietly and uncomplainingly. That is precisely why the honest assertion that God is a mere product of the human imagination is branded as the worst of all mortal sins."

Heisenberg’s view was tolerant. Pauli, raised as a Catholic, had kept silent after some initial remarks, but when finally he was asked for his opinion, said: “Well, our friend Dirac has got a religion and its guiding principle is ‘There is no God and Paul Dirac is His prophet.’” Everybody, including Dirac, burst into laughter.
[en.wikipedia.org/wiki/Paul_Dirac#Religious_views]

A rabbi, a priest, and a minister walk into a bar.

 

Despite sharing certain similar views related to science and mathematics, physicists in the modern age hold a wide range of differing views regarding religion. Einstein was a proponent of Spinoza’s god rather than a believer in a personal god. This didn’t prevent him from showing his displeasure with quantum mechanics, despite its acceptance by other physicists, by stating “God doesn’t play with dice.”

Max Planck in 1944 said, “All matter originates and exists only by virtue of a force which brings the particle of an atom to vibration and holds this most minute solar system of the atom together. We must assume behind this force the existence of a conscious and intelligent mind. This mind is the matrix of all matter.” This remark seems to indicate belief in some sort of God. Shortly before his death in 1947, however, he stated that although he had always been deeply religious, he did not believe in a personal God.

Heisenberg [in Physics and Beyond, 1971, pp. 85–86] recalls a conversation among a small group of young physicists at the 1927 Solvay Conference about Einstein and Planck’s views on religion. Wolfgang Pauli, Heisenberg and Dirac took part in it. Dirac’s contribution was a criticism of the political purpose of religion. Although known among his colleagues for his precise and taciturn nature [colleagues in Cambridge jokingly defined a unit of a dirac which was equal to one word per hour] he comes off here as quite loquacious. 

"I cannot understand why we idle discussing religion. If we are honest—and scientists have to be—we must admit that religion is a jumble of false assertions, with no basis in reality. The very idea of God is a product of the human imagination. It is quite understandable why primitive people, who were so much more exposed to the overpowering forces of nature than we are today, should have personified these forces in fear and trembling. But nowadays, when we understand so many natural processes, we have no need for such solutions. I can’t for the life of me see how the postulate of an Almighty God helps us in any way. What I do see is that this assumption leads to such unproductive questions as why God allows so much misery and injustice, the exploitation of the poor by the rich and all the other horrors He might have prevented. If religion is still being taught, it is by no means because its ideas still convince us, but simply because some of us want to keep the lower classes quiet. Quiet people are much easier to govern than clamorous and dissatisfied ones. They are also much easier to exploit. Religion is a kind of opium that allows a nation to lull itself into wishful dreams and so forget the injustices that are being perpetrated against the people. Hence the close alliance between those two great political forces, the State and the Church. Both need the illusion that a kindly God rewards—in heaven if not on earth—all those who have not risen up against injustice, who have done their duty quietly and uncomplainingly. That is precisely why the honest assertion that God is a mere product of the human imagination is branded as the worst of all mortal sins."

Heisenberg’s view was tolerant. Pauli, raised as a Catholic, had kept silent after some initial remarks, but when finally he was asked for his opinion, said: “Well, our friend Dirac has got a religion and its guiding principle is ‘There is no God and Paul Dirac is His prophet.’” Everybody, including Dirac, burst into laughter.

[en.wikipedia.org/wiki/Paul_Dirac#Religious_views]

A Short Treatise on Boojums and Snarks
   
In the midst of the word he was trying to say
In the midst of his laughter and glee
He had softly and suddenly vanished away
For the Snark was a Boojum, you see.
                                      -Lewis Carroll (The Hunting of the Snark)
                                       Illustration by Henry Holiday
   
The electron is a subatomic particle with a negative elementary electric charge.  The concept of an indivisible quantity of electric charge was theorized to explain the chemical properties of atoms, beginning in 1838. The name electron was introduced for this charge in 1894. In 1896, the British physicist J. J. Thomson demonstrated the existence of the electron.
The proton was first theorized in 1815. It was discovered by Ernest Rutherford between 1917 and 1919 and named by him in 1920. The first use of the word “proton” in the scientific literature appears in that year. The neutron was theorized by Rutherford in 1920 and discovered by James Chadwick in 1932.
In 1931 Paul Dirac predicted the existence of an as-yet unobserved particle that he called an “anti-electron” that would have the same mass as an electron but opposite electric charge and that would mutually annihilate upon contact with an electron.
The positron was the first evidence of antimatter and was discovered by Carl D. Anderson in 1932. Anderson also coined the term positron (a contraction of “positive electron”.) Thus far the naming game had been largely a matter of personal choice combined with application of old Latin and Greek roots to new concepts, but it was about to become a matter of accidents of history and preservation of convention.
The existence of the antiproton was experimentally confirmed in 1955 and the antineutron was discovered shortly thereafter in 1956. As the proton and neutron had already been assumed to be matter particles and had been so named, it was logical enough to name the new particles antiparticles. This was the beginning of the slide down a very slippery slope. The misnaming of the up quark and up antiquark would soon follow in 1964. That was likely the last nail in the coffin of rational nomenclature of subatomic particles and the point of no return (though to be fair the truth of this could not yet be seen at that point in history.)

A Short Treatise on Boojums and Snarks

 

In the midst of the word he was trying to say
In the midst of his laughter and glee
He had softly and suddenly vanished away
For the Snark was a Boojum, you see.

                                      -Lewis Carroll (The Hunting of the Snark)

                                       Illustration by Henry Holiday

 

The electron is a subatomic particle with a negative elementary electric charge.  The concept of an indivisible quantity of electric charge was theorized to explain the chemical properties of atoms, beginning in 1838. The name electron was introduced for this charge in 1894. In 1896, the British physicist J. J. Thomson demonstrated the existence of the electron.

The proton was first theorized in 1815. It was discovered by Ernest Rutherford between 1917 and 1919 and named by him in 1920. The first use of the word “proton” in the scientific literature appears in that year. The neutron was theorized by Rutherford in 1920 and discovered by James Chadwick in 1932.

In 1931 Paul Dirac predicted the existence of an as-yet unobserved particle that he called an “anti-electron” that would have the same mass as an electron but opposite electric charge and that would mutually annihilate upon contact with an electron.

The positron was the first evidence of antimatter and was discovered by Carl D. Anderson in 1932. Anderson also coined the term positron (a contraction of “positive electron”.) Thus far the naming game had been largely a matter of personal choice combined with application of old Latin and Greek roots to new concepts, but it was about to become a matter of accidents of history and preservation of convention.

The existence of the antiproton was experimentally confirmed in 1955 and the antineutron was discovered shortly thereafter in 1956. As the proton and neutron had already been assumed to be matter particles and had been so named, it was logical enough to name the new particles antiparticles. This was the beginning of the slide down a very slippery slope. The misnaming of the up quark and up antiquark would soon follow in 1964. That was likely the last nail in the coffin of rational nomenclature of subatomic particles and the point of no return (though to be fair the truth of this could not yet be seen at that point in history.)

In the 1920s the young English physicist Paul Dirac began trying to understand and describe the space-time evolution of the electron, the first elementary particle discovered by J.J. Thomson in 1897. Dirac was puzzled by an unprecedented property of space-time, discovered by Lorentz in his studies of electromagnetic forces, whereby if space was real, time had to be imaginary, and vice versa. In other words, space and time had to be a ‘complex’ mixture of two quantities, one real and the other imaginary.

Antonino Zichichi (born 1929), an Italian physicist who has worked in the field of nuclear physics [in ETTORE MAJORANA: GENIUS AND MYSTERY, p.24 found online at www.ccsem.infn.it/em/EM_genius_and_mystery.pdf] This is a fascinating, if somewhat technical, account of the history of the development of a number of pivotal ideas in early quantum mechanics.

Neutrino-less double-beta decay
   

[Some] experimenters are trying to measure the absolute mass scale of the neutrino through a process called “neutrino-less double-beta decay.” In this phenomenon, two beta decays occur simultaneously; the neutrino emitted in one decay is absorbed in the second, so that only two electrons emerge. This type of decay is possible only if neutrinos are their own antiparticles, otherwise known as Majorana neutrinos. (If neutrinos and anti-neutrinos are distinct from one another, they are called “Dirac neutrinos.”) Because neutrino-less double-beta decay is extremely rare, experiments intended to differentiate between the Majorana and Dirac scenarios take place deep underground, insulated from cosmic rays and other radioactive backgrounds. The distinction is significant because it might have played a role in the asymmetry between matter and antimatter.
[www.learner.org/courses/physics/unit/text.html?unit=1&secNum=6]

Neutrino-less double-beta decay

 

[Some] experimenters are trying to measure the absolute mass scale of the neutrino through a process called “neutrino-less double-beta decay.” In this phenomenon, two beta decays occur simultaneously; the neutrino emitted in one decay is absorbed in the second, so that only two electrons emerge. This type of decay is possible only if neutrinos are their own antiparticles, otherwise known as Majorana neutrinos. (If neutrinos and anti-neutrinos are distinct from one another, they are called “Dirac neutrinos.”) Because neutrino-less double-beta decay is extremely rare, experiments intended to differentiate between the Majorana and Dirac scenarios take place deep underground, insulated from cosmic rays and other radioactive backgrounds. The distinction is significant because it might have played a role in the asymmetry between matter and antimatter.

[www.learner.org/courses/physics/unit/text.html?unit=1&secNum=6]

Majorana’s neutrinos
   

Today, Majorana is particularly well known for his ideas about neutrinos. Bruno Pontecorvo, the “father” of neutrino oscillations, recalls the origin of Majorana neutrinos in the following way: Dirac discovers his famous equation describing the evolution of the electron; Majorana goes to Fermito point out a fundamental detail: ” I have found a representation where all Dirac γ matrices are real. In this representation it is possible to have a real spinor that describes a particle identical to its antiparticle.”
The Dirac equation needs four components to describe the evolution in space and time of the simplest of particles, the electron; it is like saying that it takes four wheels (like a car) to move through space and time. Majorana jotted down a new equation: for a chargeless particle like the neutrino, which is similar to the electron except for its lack of charge, only two components are needed to describe its movement in space-time - as if it uses two wheels (like a motorcycle). 
"Brilliant," said Fermi, "Write it up and publish it." Remembering what happened with the neutron discovery, Fermi wrote the article himself and submitted the work under Majorana’s name to the prestigious scientific journal Il Nuovo Cimento (Majorana 1937). Without Fermi’s initiative, we would know nothing about the Majorana spinors and Majorana neutrinos.
[cerncourier.com/cws/article/cern/29664]

Majorana’s neutrinos

 

Today, Majorana is particularly well known for his ideas about neutrinos. Bruno Pontecorvo, the “father” of neutrino oscillations, recalls the origin of Majorana neutrinos in the following way: Dirac discovers his famous equation describing the evolution of the electron; Majorana goes to Fermito point out a fundamental detail: ” I have found a representation where all Dirac γ matrices are real. In this representation it is possible to have a real spinor that describes a particle identical to its antiparticle.”

The Dirac equation needs four components to describe the evolution in space and time of the simplest of particles, the electron; it is like saying that it takes four wheels (like a car) to move through space and time. Majorana jotted down a new equation: for a chargeless particle like the neutrino, which is similar to the electron except for its lack of charge, only two components are needed to describe its movement in space-time - as if it uses two wheels (like a motorcycle). 

"Brilliant," said Fermi, "Write it up and publish it." Remembering what happened with the neutron discovery, Fermi wrote the article himself and submitted the work under Majorana’s name to the prestigious scientific journal Il Nuovo Cimento (Majorana 1937). Without Fermi’s initiative, we would know nothing about the Majorana spinors and Majorana neutrinos.

[cerncourier.com/cws/article/cern/29664]

Quantum Electrodynamics III
   

In 1926 the British physicist P.A.M. Dirac laid the foundations for QED with his discovery of an equation describing the motion and spin of electrons that incorporated both the quantum theory and the theory of special relativity. The QED theory was refined and fully developed in the late 1940s by Richard P. Feynman, Julian S. Schwinger, and Shin’ichiro Tomonaga, independently of one another. QED rests on the idea that charged particles (e.g., electrons and positrons) interact by emitting and absorbing photons, the particles of light that transmit electromagnetic forces. These photons are virtual; that is, they cannot be seen or detected in any way because their existence violates the conservation of energy and momentum. The particle exchange is merely the “force” of the interaction, because the interacting particles change their speed and direction of travel as they release or absorb the energy of a photon.
Photons also can be emitted in a free state, in which case they may be observed. The interaction of two charged particles occurs in a series of processes of increasing complexity. In the simplest, only one virtual photon is involved; in a second-order process, there are two; and so forth. The processes correspond to all the possible ways in which the particles can interact by the exchange of virtual photons, and each of them can be represented graphically by means of the diagrams developed by Feynman. Besides furnishing an intuitive picture of the process being considered, this type of diagram prescribes precisely how to calculate the variable involved.
Under QED, charged particles interact by the exchange of virtual photons, photons that do not exist outside of the interaction and only serve as carriers of momentum/force. [See above diagram.] Notice the elimination of action at a distance, the interaction is due to direct contact of the photons.
In the 1960’s, a formulation of QED led to the unification of the theories of weak and electromagnetic interactions. This new force, called electroweak, occurs at extremely high temperatures such as those found in the early Universe and reproduced in particle accelerators. Unification means that the weak and electromagnetic forces become symmetric at this point, they behave as if they were one force.
Electroweak unification gave rise to the belief that the weak, electromagnetic and strong forces can be unified into what is called the Standard Model of matter.
[abyss.uoregon.edu/~js/21st_century_science/lectures/lec17.html]

Quantum Electrodynamics III

 

In 1926 the British physicist P.A.M. Dirac laid the foundations for QED with his discovery of an equation describing the motion and spin of electrons that incorporated both the quantum theory and the theory of special relativity. The QED theory was refined and fully developed in the late 1940s by Richard P. Feynman, Julian S. Schwinger, and Shin’ichiro Tomonaga, independently of one another. QED rests on the idea that charged particles (e.g., electrons and positrons) interact by emitting and absorbing photons, the particles of light that transmit electromagnetic forces. These photons are virtual; that is, they cannot be seen or detected in any way because their existence violates the conservation of energy and momentum. The particle exchange is merely the “force” of the interaction, because the interacting particles change their speed and direction of travel as they release or absorb the energy of a photon.

Photons also can be emitted in a free state, in which case they may be observed. The interaction of two charged particles occurs in a series of processes of increasing complexity. In the simplest, only one virtual photon is involved; in a second-order process, there are two; and so forth. The processes correspond to all the possible ways in which the particles can interact by the exchange of virtual photons, and each of them can be represented graphically by means of the diagrams developed by Feynman. Besides furnishing an intuitive picture of the process being considered, this type of diagram prescribes precisely how to calculate the variable involved.

Under QED, charged particles interact by the exchange of virtual photons, photons that do not exist outside of the interaction and only serve as carriers of momentum/force. [See above diagram.] Notice the elimination of action at a distance, the interaction is due to direct contact of the photons.

In the 1960’s, a formulation of QED led to the unification of the theories of weak and electromagnetic interactions. This new force, called electroweak, occurs at extremely high temperatures such as those found in the early Universe and reproduced in particle accelerators. Unification means that the weak and electromagnetic forces become symmetric at this point, they behave as if they were one force.

Electroweak unification gave rise to the belief that the weak, electromagnetic and strong forces can be unified into what is called the Standard Model of matter.

[abyss.uoregon.edu/~js/21st_century_science/lectures/lec17.html]