What Is Real?: The Unfinished Quest for the Meaning of Quantum Physics

by Adam Becker

The soundest fact may fail or prevail in the style of its telling. —Ursula K. Le Guin

The objects in our everyday lives have an annoying inability to appear in two places at once. Leave your keys in your jacket, and they won’t also be on the hook by the front door. This isn’t surprising—these objects have no uncharted abilities or virtues. They’re profoundly ordinary. Yet these mundane things are composed of a galaxy of the unfamiliar. Your house keys are a temporary alliance of a trillion trillion atoms, each forged in a dying star eons ago, each falling to Earth in its earliest days. They have bathed in the light of a violent young sun. They have witnessed the entire history of life on our planet. Atoms are epic.

Despite his crucial role in the development of quantum physics, Einstein couldn’t stand the Copenhagen interpretation. He called it a “tranquilizing philosophy—or religion” that provides a “soft pillow to the true believer… [but it] has so damned little effect on me.” Einstein demanded an interpretation of quantum physics that told a coherent story about the world, one that allowed answers to questions even when no measurement was taking place. He was exasperated with the Copenhagen interpretation’s refusal to answer such questions, calling it an “epistemology-soaked orgy.”

Everything has a wave function in quantum physics: this book, the chair you’re sitting in, even you. So do the atoms in the air around you, and the electrons and other particles inside those atoms. An object’s wave function determines its behavior, and the behavior of an object’s wave function is determined in turn by the Schrödinger equation, the central equation of quantum physics, discovered in 1925 by the Austrian physicist Erwin Schrödinger. The Schrödinger equation ensures that wave functions always change smoothly—the number that a wave function assigns to a particular location never hops instantly from 5 to 500. Instead, the numbers flow perfectly predictably: 5.1, 5.2, 5.3, and so on. A wave function’s numbers can go up and down again, like a wave—hence the name—but they’ll always undulate smoothly like waves too, never jerking around too crazily.

The wave function doesn’t tell you how much of the electron is in one place—it tells you the probability that the electron is in that place. The predictions of quantum physics are generally in terms of probabilities, not certainties. And that’s strange, because the Schrödinger equation is totally deterministic—probability doesn’t enter into it at all. You can use the Schrödinger equation to predict with perfect accuracy how any wave function will behave, forever. Except that’s not quite true either. Once you do find that electron, a funny thing happens to its wave function. Rather than following the Schrödinger equation like a good wave function, it collapses—it instantly becomes zero everywhere except in the place where you found the electron. Somehow, the laws of physics seem to behave differently when you make a measurement: the Schrödinger equation holds all the time, except when you make a measurement, at which point the Schrödinger equation is temporarily suspended and the wave function collapses everywhere except a random point. This is so weird that it gets a special name: the measurement problem

“When a mouse observes, does that change the [quantum] state of the universe?” Einstein once asked. Bell asked, “Was the world wavefunction waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer for some more highly qualified measurer—with a Ph.D.?”

And the name “relativity” itself, which suggests a rejection of absolutes, was introduced by the physicist Max Planck, not Einstein—Einstein disliked the name “relativity” precisely because it connoted a kind of relativism. He preferred the name “invariant theory,” which conjures up a very different set of associations. (The “invariants” in relativity are quantities like spacetime that all observers agree upon—and there are many of these in the theory.)

For nearly two decades, almost nobody other than Einstein believed in photons. Even Planck himself didn’t think his work suggested that light was made of particles (though, years later, Planck’s work was hailed as the start of the quantum revolution). Only when Arthur Compton actually caught photons in the act of bouncing off of electrons, in 1923, did the physics community finally come around to Einstein’s way of thinking—and even then there were a few holdouts.

As Schrödinger soon discovered, matrix mechanics and wave mechanics were mathematically equivalent, using different tools to describe the same ideas: a single new theory of quantum mechanics. Problems like the brightness of spectral lines had been solved first with wave mechanics only because Schrödinger’s equation was mathematically easier to handle than Heisenberg’s matrices in most situations. But the two versions of quantum mechanics still differed radically in their interpretation. Schrödinger was sure that he could find a way to interpret all quantum phenomena as the smooth movement of the waves his equation described. Heisenberg was unconvinced. “The more I think about the physical portion of the Schrödinger theory, the more repulsive I find it,” he wrote to Pauli. “What Schrödinger writes about the visualizability of his theory is ‘probably not quite right,’ in other words it’s crap.”

Heisenberg started thinking about what would happen if you tried to measure the position of a single particle, like an electron, to very high precision. He realized that you could do this the same way you’d look for a lost wallet in a dark field: shine a flashlight around until you’ve found what you’re looking for. An ordinary flashlight wouldn’t work for an electron, though—the wavelength of visible light is far too large for that. But Heisenberg knew you could find an electron using higher-energy light, with a shorter wavelength: gamma rays. Shine a gamma-ray flashlight around the room, and you’ll find your electron. But gamma rays pack a punch—bounce one gamma-ray photon off an electron, and the electron will go careening off in some random direction. So you’ll know where the electron was, but you won’t know how fast it’s going or where it’s heading now. Heisenberg wondered if this kind of trade-off between measuring an object’s position and its momentum was unavoidable, or if it was just an artifact of his thought experiment. To his delight, he discovered that these limits on measurement were fundamental: buried in the mathematics of Schrödinger’s wave mechanics, Heisenberg found a precise formulation of how much information you have to give up about an object’s momentum in order to learn more about its position, and vice versa. You could know a lot about where an object was or a lot about how it was moving—but you couldn’t know both at the same time.

At Bohr’s urging, Heisenberg used the term “uncertainty principle” to describe this insight. Heisenberg’s uncertainty paper paid off as he had hoped: the University of Leipzig again offered him a tenured professorship. He accepted, and in June 1927, Heisenberg, at twenty-five, became the youngest tenured professor in all of Germany.

In other words, one could not ask what was really happening inside of an atom when nobody looked—according to Bohr, the quantum world could only be considered real in conjunction with some kind of measurement apparatus to study that world. And the behavior of the objects in that world, as indicated by such an apparatus, would be best described as either particles or waves, but never both simultaneously. These descriptions are contradictory—a particle has a definite location, which waves don’t; waves have frequencies and wavelengths, which particles don’t—yet Bohr claimed that this “inevitable dilemma” was not a problem for quantum physics. “We are not dealing with contradictory but with complementary pictures of the phenomena,” claimed Bohr, which are “indispensable for a description of experience.”

This “wave-particle duality” shows up in all quantum phenomena. For example, in an old cathode-ray-tube TV, electrons shoot from the back of the TV toward the phosphorescent screen at the front of the TV, which lights up when an electron hits it. When an electron is shot out into the tube, its wave function obeys the Schrödinger equation, undulating and propagating outward like a wave. But when the electron hits the phosphorescent screen, it hits in one location, lighting up a particular spot on the screen, like a particle. So sometimes the electron behaves like a wave, and sometimes it behaves like a particle, but never both. According to Bohr, there cannot be a more complete description of an electron, or of anything—merely incomplete and incompatible analogies that never overlap. This, Bohr said, was the heart of complementarity, and it was inevitable and unavoidable.

But Bohr was wrong. There was nothing inevitable or necessary about complementarity—other interpretations of quantum physics are possible. Indeed, the claim of inevitability is an awfully strong and strange claim to make about any interpretive issue in science, precisely because it is always possible to reinterpret any theory. Yet Bohr was convinced that complementarity was the deepest insight into nature found within the quantum theory.

Quantum physics, in short, shouldn’t be taken seriously as a theory of the way the world actually is. Instead, quantum physics is a mere tool, an instrument for predicting the outcomes of measurements. Yet, strangely, its unseriousness should be taken very seriously: in claiming their version of quantum physics as a “closed theory,” Heisenberg and Born were ruling out the possibility of an explanation of the quantum world, independent of observation, even in principle.

Schrödinger’s observation that entanglement shows up throughout quantum physics only deepened the problem for the Copenhagen interpretation. For any entangled system, Einstein’s choice applied: either the system is nonlocal, or quantum physics can’t fully describe all the features of that system. And Schrödinger had just shown that nearly any quantum interaction would result in an entangled system. Thus, the challenge the EPR paper posed wasn’t limited to some tiny corner of quantum physics—it was deeply embedded in the fundamental structure of the theory.

But Einstein’s fears that the forced choice between nonlocality and incompleteness had been smothered in the EPR paper were sadly justified. In a letter to Einstein, Schrödinger vented his frustration over how badly other physicists had missed the point: “It is as if one person said, ‘It is bitter cold in Chicago’; and another answered, ‘That is a fallacy, it is very hot in Florida.’”

Einstein’s concerns had little, if anything, to do with determinism—they were about the importance of locality and a physical reality that exists independently of anyone observing it. Quantum physics, said Einstein, “avoids reality and reason.” In his view, physics had been led astray by following Bohr. Writing to Schrödinger, Einstein described Bohr as a “talmudic philosopher [who] doesn’t give a hoot for ‘reality,’ which he regards as a hobgoblin of the naive.”

“The idea of an objective real world whose smallest parts exist objectively in the same sense as stones or trees exist, independently of whether or not we observe them,” Heisenberg said, “is impossible.” How, then, does our world of stones and trees emerge from the world of atoms and molecules? “The transition from the ‘possible’ to the ‘actual’ takes place during the act of observation,” said Heisenberg. And what happens when we’re not looking? According to Heisenberg, that question can’t even be asked. “If we want to describe what happens in an atomic event, we have to realize that the word ‘happens’ can apply only to the observation, not to the state of affairs between two observations.” And what about the measurement problem? What makes observation so special? Whatever it is, it is “physical,” not “psychical,” said Heisenberg. “The transition from the ‘possible’ to the ‘actual’ takes place as soon as the interaction of the object with the measuring device, and thereby with the rest of the world, has come into play; it is not connected with the act of registration of the result by the mind of the observer.” Yet on the question of what constituted a “measuring device” and why it obeyed different rules than the quantum world, Heisenberg was infuriatingly unclear. Nowhere in his lectures did he propose anything like a solution to the measurement problem.

Von Neumann’s solution was to make the observer—whoever was looking—responsible for wave function collapse. “We must always divide the world into two parts, the one being the observed system, the other the observer,” Von Neumann said. “Quantum mechanics describes the events which occur in the observed portion of the world, so long as they do not interact with the observing portion, with the aid of the [Schrödinger equation], but as soon as such an interaction occurs, i.e. a measurement, it requires the [collapse of the wave function].” It’s not entirely clear what von Neumann meant by this. Some took him to be saying that consciousness itself causes the collapse of the wave function; this was a view promoted by physicists Fritz London and Edmond Bauer in a book they wrote several years later, heavily influenced by von Neumann’s work. Wigner also adopted this view later. But this is a weird view. Stating that consciousness collapses wave functions does arguably solve the measurement problem but only at the price of introducing new problems. How could consciousness cause wave function collapse? Since wave function collapse violates the Schrödinger equation, does that mean that consciousness has the ability to temporarily suspend or alter the laws of nature? How could this be true? And what is consciousness anyhow? Who has it? Can a chimp collapse a wave function? How about a dog? A flea? “Solving” the measurement problem by opening the Pandora’s box of paradoxes associated w...

The nuclear struggle between the sticky strong force and the repellent electrical force ultimately depends on the size of the nucleus. For small nuclei, the strong force wins out easily, and adding more protons and neutrons generally just makes it stronger. But the strong force can only act over very short distances, comparable to the size of a proton itself—anything much larger than a trillionth of a millimeter (a distance known as one fermi, after Enrico) is too much for it. After a certain point, the nucleus gets too big, the electric force starts to win the tug-of-war, and nuclei become weaker as more protons and neutrons are added. Specifically, that point is around nickel (28 protons and 34 neutrons) and iron (26 protons and 30–32 neutrons). Bigger nuclei than that are less stable, and beyond a certain size—namely lead, which has 82 protons and over 100 neutrons—there are no stable nuclei at all.

Bohr and Wheeler, building on the work of refugee physicists Lise Meitner and her nephew Otto Frisch, found that the two isotopes of uranium have very different nuclear properties. Specifically, hitting a U-235 nucleus with a neutron leads the nucleus to fission: it splits into two smaller nuclei, releasing a fabulous quantity of energy, along with a few free-floating neutrons. With enough U-235—a critical mass—the neutrons left over from fission will hit more U-235 nuclei, which will split in turn, releasing even more neutrons and starting a chain reaction. Left uncontrolled in 120 pounds of pure U-235—a small sphere of the dense metal, less than twenty centimeters across—a nuclear chain reaction would explode with the power of 15,000 tons of TNT, enough to instantly level a small city. Controlling the reaction by absorbing some of the excess neutrons would allow you to power a small city instead, for days on end, with the same 120 pounds of U-235. U-238 is a different story. Those three extra neutrons give it a little more stability, so hitting it with a neutron won’t split it as easily. This makes it impossible to build a bomb out of U-238. And fortunately, about 99.3 percent of uranium in nature is U-238. To build an atomic bomb, you would need to separate the tiny quantity of U-235 from the enormous bulk of U-238—and since they’re chemically identical, the only way to separate them is to take advantage of the fact that U-238 is 1.3 percent heavier than U-235. This gua...

Research into the meaning of quantum physics was one of the casualties of the war. With all these new students crowding classrooms around the country, professors found it impossible to teach the philosophical questions at the foundations of quantum physics. Before the war, courses in quantum physics on both sides of the Atlantic, like Heisenberg’s in Leipzig and Oppenheimer’s in Berkeley, spent a great deal of time on conceptual issues. Textbooks and exams from the prewar period asked students to write detailed essays on the nature of the uncertainty principle and the role of the observer in the quantum world. But, with ballooning class sizes, detailed discussion of philosophy became all but impossible. “With these subjects [such as uncertainty, complementarity, and causality] lecturing is of little avail,” complained a physics professor at the University of Pittsburgh in 1956. “The baffled student hardly knows what to write down, and what notes he does take are almost certain to horrify the instructor.” Smaller quantum physics classes in smaller departments afforded foundational questions more time—about five times as much as larger classes—but, as enrollments surged, few small physics classes were left. The larger classes focused on “efficient, repeatable means of calculation,” rather than focusing on foundations. And textbooks nearly dropped questions about foundations altogether, as a new generation of reviewers in physics periodicals praised a new batch of texts for “...

Bohm accounted for the strange results of the double-slit experiment by doing exactly what the Copenhagen interpretation said was impossible: he gave a detailed account of what happens in the quantum world whether or not anyone is looking. Photons, according to Bohm, are particles surfing on waves. While a particle can only pass through one slit, its pilot wave passes through both and interferes with itself. That self-interference, in turn, affects the motion of the particle, because it is guided by the wave. The wave pushes the particle onto a path ensuring the appearance of an interference pattern on the photographic plate after enough photons have been sent through the double slit (Figure 5.4). Putting photon detectors on each slit affects each photon’s pilot wave—no matter how ingenious the design, any photon detector must alter a photon’s pilot wave, as ensured by Heisenberg’s uncertainty principle, which in Bohm’s interpretation places limits on how much measuring devices can avoid interfering with the things they attempt to measure. The effect of these measurements on the photons’ pilot waves alters their trajectories, causing them to form a pair of clusters on the photographic plate rather than an interference pattern. In Bohm’s account, although measurement can influence a particle’s motion, all particles have definite positions whether or not anyone is looking at them.

This was a truly radical idea: taking quantum physics seriously as a way of accounting for the entire world. In Bohm’s pilot-wave interpretation, strange quantum behaviors are minimized for larger objects, which is why we don’t see them in the everyday world. But every object, big and small, is ultimately governed by the same set of quantum equations.

(“On quantum theory I use up more brain grease than on relativity,” Einstein once told his friend Otto Stern.)

The problem, in a nutshell, is this: Quantum wave functions move along nice and smoothly, always obeying one simple and deterministic law, the Schrödinger equation—except when they don’t. When a measurement happens, wave functions collapse. How and why wave function collapse happens—and what constitutes a “measurement” anyway—is the measurement problem, the central puzzle of quantum physics.

As you interact with the things in your environment, they get entangled with you, and then other things get entangled with them, and so on. Eventually, we have a single complicated and messy wave function for the entire universe—the universal wave function. And as more events happen, that universal wave function splits into more and more noninteracting parts, each merrily marching along to the deterministic beat of the Schrödinger equation. These are the many worlds of Everett’s interpretation. They may seem absurd on the face of it: there is, after all, only one world that we experience. But if that’s your objection, Everett’s reply is that you’re hardly alone: to each person in each branch of the universal wave function, their world appears to be the only world, just as there appeared to be only one cat in the box and one you looking at it. This is a hallmark of the many-worlds interpretation: the appearance of a single world, despite the true existence of many.

A hidden-variables interpretation assigns definite locations or other properties to quantum objects before they are observed, even if those properties can’t be calculated from the theory itself. These properties go unseen in the mathematics of quantum physics, hence “hidden” variables. Bohm’s pilot-wave interpretation is a prime example of such a theory: in Bohm’s world, particles always have positions, even though those positions are largely hidden from view and can’t be calculated from Schrödinger’s equation.

You can’t look at the quantum world without altering it—but that doesn’t mean the quantum world isn’t there before you look. Quite the opposite: if it weren’t there, you wouldn’t be able to alter it by looking!

A contextual roulette wheel can exist—it’s just that the ball’s location will change when you look at it in different ways, because you can’t separate the behavior of the ball from its interaction with you when you look at it. That doesn’t mean the ball doesn’t exist or that it doesn’t have a location before you look; it just means the ball is kind of jumpy and sensitive, moving around dramatically at even the slightest disturbance. The hidden variables in Bohm’s pilot-wave interpretation behave in exactly this way. Particles, according to Bohm, always have positions—but those positions can be dramatically altered by small disturbances and changes in experimental setups. Ask a slightly different set of questions to an electron, in Bohm’s world, and you can get an enormously different set of answers—but the electron has a definite position all the while. And because Bohm’s theory is contextual, it evades all of the proofs that supposedly rule it out. “What is proved by impossibility proofs,” concluded Bell, “is lack of imagination.”

Assuming that nature is local, then the only explanation for the perfectly synchronized long-distance choreography of the entangled photons is that they have a prearranged dance routine, one that they agreed upon before flying off from their common source. But the wave function shared by the entangled photons says nothing about any kind of prearrangement. It just guarantees that the photons will always do the same thing at polarizers with the same settings, that they will be perfectly correlated. Therefore, if nature is local, the wave function is not everything—there must be hidden variables. So either quantum physics is incomplete, or nature is nonlocal. We cannot have both locality and completeness in quantum physics. This is Einstein’s forced choice, the heart of the EPR argument.

Bell’s stroke of brilliance was to consider imperfection, rather than perfection. After all, the perfect correlations in the EPR-Bohm setup are easily compatible with locality—the photons could be sharing hidden instruction sets at their common origin. But if you rotate the axis of one of the polarizers, quantum physics predicts that pairs of entangled photons arriving at the polarizers will no longer behave in exactly the same way every time. And Bell showed that the imperfect correlations predicted by quantum physics were too strong for any local theory of nature to be able to account for them. So either the predictions of quantum physics are wrong and nature can be local, or quantum physics is right and “spooky action at a distance” is real. Bell had discovered a remarkably profound and counterintuitive truth about the world. Bell had also shown that there was an experimental test that could decide between the two options. All someone had to do was actually construct and perform Bell’s modified version of the EPR thought experiment, or another experiment along those lines involving entangled particles. If the results showed that Bell’s inequality was violated, quantum physics was safe but nature was nonlocal; if his inequality held, then quantum physics was wrong but nature could be local. Bell’s impossibility proof had taken the question of nonlocality out of the realm of debate and turned it into an experimental challenge. This proof, now known as Bell’s theorem, has ...

Hilary Putnam put it more succinctly. “Realism,” he claimed, “is the only philosophy that doesn’t make the success of science a miracle.”

The philosophers had successfully overthrown positivism and had a good understanding of the mathematical intricacies of quantum physics—but the physicists were still blinkered, walled off from philosophy and the developments there. They had no idea any of this had happened. While Einstein and Bohr’s generation was widely schooled in philosophy, the push toward specialization after World War II had taken its toll on the liberal arts education of the new crop of physicists. Academic departments had become Balkanized as they had grown in the postwar boom, and physicists, busy with enormous grants and hard-nosed calculations, were generally dismissive of philosophy. So physics trudged along, not knowing that a major revolution had happened in an adjacent field. And philosophers were, mostly, not surprised by this.

“Unless the real difficulties in quantum mechanics can be dealt with,” wrote Smart, “the philosophical objections to the Copenhagen interpretation, which consist only in exposing the positivistic preconceptions thereof, will be found unsatisfactory by physicists.”

The similarities to the many-worlds interpretation’s multiverse were not lost on quantum cosmologists. The appearance of multiverses independent of Everett’s interpretation made its strange profusion of worlds downright appealing. Some physicists even proposed that all three of these multiverses—Everettian many-worlds, eternal inflation, and the string landscape—were in fact a single multiverse, and the three theories were simply describing the same reality in different ways. In any case, the many-worlds interpretation was (mostly) no longer laughed out of the room without serious consideration. Indeed, by the start of the twenty-first century, many-worlds had become the most popular rival to the Copenhagen interpretation itself among physicists, with particular popularity among cosmologists.

Claiming, then, that multiverse theories are unscientific because they are unfalsifiable is to reject them simply because they do not live up to an arbitrary standard that no scientific theory of any kind has ever met. Claiming that no data could ever force the rejection of a multiverse theory is merely stating that a multiverse theory is just like any other theory.

Ultimately, arguments against a multiverse purportedly based on falsifiability are really arguments based on ignorance and taste: some physicists are unaware of the history and philosophy of their own field and find multiverse theories unpalatable. But that does not mean that multiverse theories are unscientific.

H. L. Mencken once said, “There is always a well-known solution to every human problem—neat, plausible, and wrong.”

“Copenhagen interpretation” and never really was. “The name ‘Copenhagen interpretation’ has gotten pretty slippery,” said Nina Emery, a philosopher of physics at Mt. Holyoke. “The semantic confusion makes it easy for physicists to avoid dealing with those flaws directly. For instance, when you push them on the idea that measurements cause collapse… they shift and start talking about some kind of Bohrian view or about the [mathematics of the theory]. And if you point out the issues with those views (e.g. who knows what the former is; and the latter isn’t even a complete interpretation), they go back to talking about [measurements causing collapse].” The flexibility afforded by these contradictory positions makes it easy to fend off any attacks on “the” Copenhagen interpretation.

Yet philosophers have known for more than half a century that the positivism underpinning statements like these is fundamentally flawed. And philosophers of physics today almost unanimously reject the Copenhagen interpretation. (Logical empiricism of a sort has made a comeback since 1980, but scientific realism is still the standard position among philosophers of physics—and even the most staunch defenders of empiricism today agree that the sort of naive positivism deployed in standard defenses of Copenhagen doesn’t work.) How have physicists failed to get the memo from philosophers after all this time? Part of the problem is that physicists generally don’t know much about philosophy. There is a massive asymmetry between the two fields: while philosophers usually take physics very seriously indeed—philosophers of physics are mathematically conversant in physics and often have advanced degrees in both fields—physicists are rarely trained in philosophy at all. Despite their ignorance of philosophy (or more likely because of their ignorance), some physicists are openly contemptuous of the subject. “Philosophy is dead,” declared Stephen Hawking in 2011. “Philosophers have not kept up with modern developments in science. Particularly physics.” And according to Neil deGrasse Tyson, studying philosophy “can really mess you up.” “Pretty much after quantum mechanics… philosophy has basically parted ways from the frontier of the physical sciences,” Tyson claimed. “I’m disappointed b...

If I were forced to sum up in one sentence what the Copenhagen interpretation says to me,” wrote the physicist David Mermin in 1989, “it would be ‘Shut up and calculate!’” Mermin followed his summary with a quick rejoinder—“But I won’t shut up.” Yet the phrase “shut up and calculate” took on a life of its own after Mermin set it to paper, and rapidly became the catchphrase of the Copenhagen interpretation among physicists. It was misattributed to Richard Feynman, and eventually even Mermin himself forgot where it came from, only to rediscover, years later, that he was the source of the phrase.

The idea that something as pervasive and central as the Copenhagen interpretation might be dominant for “accidental” nonscientific reasons can be scary, especially for people who have devoted their entire lives to physics. Once you give up Copenhagen, “there’s more than one option on the table, and if there’s more than one option on the table then how do you decide?” asks Doreen Fraser, a philosopher of physics at the University of Waterloo. “Is it because you have certain prejudices about what’s interesting and what’s not interesting? Actually that’s a large part of it, but that’s kind of uncomfortable.” This discomfort, this fear, is yet another reason why it’s tempting, as a physicist, to “shut up and calculate.” But giving in to that fear just makes it harder for us to see our biases.

There’s a wide middle ground between “science is Pure and Perfectly Rational” and “science is just some bullshit somebody made up.” There’s still plenty of room for humans to interfere in that middle ground,

Experimental results are not the only things that enter into the formulation and evaluation of scientific theories, nor could they be. The full content of our theories—not only the mathematics but the claims about the nature of the world that come along with the mathematics—is important to the work of science.

So many people today—and even professional scientists—seem to me like somebody who has seen thousands of trees but has never seen a forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is—in my opinion—the mark of distinction between a mere artisan or specialist and a real seeker after truth. —Albert Einstein