In this article , 'Evidence' will be acting as a placeholder for measurement, observation, and data. The meanings of those words should be taken as they would be used in a formal publication in a science journal, or as they would be appear in a statistics textbook.
Modern Physics
Modern physics began in history with the breakout papers of Albert Einstein in 1905, sometimes called the Miracle Year papers. While Einstein himself was only concerned with some edge cases about electromagnetism, his approach to physics later formed the foundations of an entire theoretical edifice : today we call it the theory of Special Relativity. Some arguments can be made (which are only interesting to historians) that "modern physics" properly began with Max Planck. His reasoning regarding the EM spectrum and the transmission of energy in "corpuscles" presaged the kind of reasoning seen all over modern physics.
Fig.1 Other theoretical edifices were developed through the 20th century. Those edifices constitute today the four pillars of modern physics.
In any case, the development of modern physics often proceeded by reasoning about the consequences of equations. The reasoning continued often in the complete absence of understanding what those equations were allegedly depicting. In the case of de Broglie wavelength, questions about what this "wave" was referring to are deferred and left continually un-addressed by the author. What is more relevant for this article is that the question as to what this "wave" is supposed to be, is deferred indefinitely -- even far beyond the time in which the theory makes measurable predictions.
Fig.2 Louis de Broglie asserts that not just photons, but all particles in the universe have a wavelength. The wavelength scales with the particle's momentum. Nobody in the physics department could make heads-or-tails of the claim.
By the time you get to General Relativity, the developers were producing mathematics that they themselves could not read. When Einstein first derived his field equations, he had no idea what the final equation was supposed to be saying. Several other mathematicians trained in tensor mathematics had to look over them. The mathematicians noticed a term in the equations as a Riemann metric tensor. They recognized such terms because they were used in a strange branch of math depicting non-Euclidean geometries. ALbert Einstein is excused for not knowing this kind of mathematics. Hardly anyone did at that time. (This anecdotal story is the basis to Arthur Eddington's claim that, "Only six people in Europe understand General Relativity." )
The Leather Armchair
Amateur philosophers on the internet often suppose that something in philosophy provides to them a validation for denying particular facts of measured evidence. This is usually due to some sophomoric interpretation of Cartesian Solipsism.
Religious evangelicals point to the inerrancy of their scripture as basis for denying what is plainly measured by the instruments of science.
A wise man once noted that philosophy appears to be a method of seeking Truth about reality through reason alone. This person then concluded this is a flaw of philosophy. Philosophy, in its one-track approach, has a danger of leaving out the consideration of evidence. We could ask whether this is a minor blemish in philosophy as a discipline, or whether this detachment from evidence is a deeper, more serious flaw sitting at the very heart of philosophy itself.
We can begin to make rapid in-roads to answering this question by means of a gedankenexperiment.
Namely, we will consider what would have happened to the four pillars of Modern Physics, if evidence supporting them were never considered. Instead, imagine what would have happened in the 20th century when considering only the metaphysical validity of GR, SR, QFT, and QM. Say we planted ourselves firmly in our leather armchairs, and discussed among ourselves whether these theories are logical, well-vetted, and afford to our intuitions (as Emmanuel Kant would demand.) GR, SR, QFT and QM would only be considered valid theories, if they were logical, metaphysically well-vetted, intuitive, and derivable in-whole from our current understanding of nature.
The problem is immediately obvious. Modern physics is not only slightly flavored towards incredulity. The theories are utterly unbelievable. A philosopher could not only deny the theories on psychological grounds. He could verily stand at a podium with a powerpoint presentation systematically listing how metaphysically flawed the theories are. If the philosopher were to invoke some EPR paradoxes, he may even get away with the claim that quantum mechanics is illogical. On the basis of that organized presentation, the philosopher could reject all four of the pillars of modern physics, and the rejections would be perfectly justified.
For demonstration, I will tentatively list what some of these powerpoint presentation might have looked like :
On the rejection of Quantum Mechanics
- Monsieur de Broglie has not described the nature nor the attributes of this "matter wave" he is continually referring to. Until more detail is provided on the wave's ontology, the theory is not metaphysically vetted. QM is therefore incomplete in the best case, and likely wrong in the worst case.
- Dr. Max Born has not provided to us a mechanism by which wave function collapse occurs. Without a mechanism, the theory is non-physical and therefore false. Science concerns itself with physical things.
- The Schroedinger equation suggests that massive particles could "tunnel" through barriers and appear at the opposite side on rare occasions. We know that all matter must progress through space continuously. Matter does not "jump" through space. QM is false.
On the rejection of Special Relativity
- We know that all waves in this universe are propagating in a medium. Mr. Einstein has presented a theory of wave propagation with no medium. That's unphysical and therefore wrong.
- Energy and solid matter are different phenomenon. One is not freely "convertible" to another. SR is wrong.
- Mr. Einstein refers to an observer progressing through the passage of time at a different rate. But our current understanding shows that all objects progress according to a single universal clock. This theory contradicts our current understanding of time, and therefore must be wrong.
On the rejection of General Relativity
- We cannot attribute particular states to space, as space is not an extended object. Nothingness has no predication, and space is nothingness. So we cannot predicate space with being curved or 'having curvature'. GR is wrong.
- There is no a priori reason why distances in space will co-vary with intervals in time. Time intervals and space distances are separable as our current understanding shows. GR cannot be derived from our current theories in a logical way, and is false on that account.
On the rejection of QFT
- This theory suggests that space is occupied by small fluctuations. But Empty space between objects is nothingness, a void. QFT is wrong.
- No one has observed so-called "anti-particles". But QFT predicts their existence. QFT is therefore a wrong theory of nature.
- QFT does not provide a mechanism for particle decay events. Without describing a mechanism, the theory lacks metaphysical vettedness, and should be ignored.
- The Path Integral takes into account future states of trajectory. But the future does not exist yet. Therefore, the path integral could never be useful in predicting a particle's behavior in the present time.
Go, and test It
We can imagine a situation in which two philosophers debate , dispute, and discuss the logical, metaphysical, and epistemic plusses and minuses of modern physics, using several of the observations listed above. They perform their reasoning in a teacher's lounge, hermetically sealing themselves off from the considerations of measurement and evidence. After having conclusively agreed that modern physics is silly and obviously wrong, a third person enters the room. This newcomer asserts the claim that the universe does not accord with their intuitions, and in many cases acts contradictory to their metaphysics.
How do we go about demonstrating the newcomer's claim?
How do we -- as people, as a society, as a civilization -- go about verifying the third man's claim without measuring the world?
The third man could show how de Broglie's theory can eventually produce a prediction that hydrogen atoms only emit a certain narrow color of light. (what is known as the hydrogen fine spectra ). This particular color of light corresponds to an electron energy state where its de Broglie wave fits exactly around a hydrogen nucleus (This special wave configuration is discrete. It is the stationary state of the wave, also known as the "eigenstate" of the electron). He could extract the philosophers from their leather armchairs and take them across the hall to a lab. There he could show them hydrogen emitting that exact frequency of light, just as predicted. The philosophical puzzles about the "Wave" remain unresolved and unaddressed, while deeming the theory wrong is suddenly irrational.
QFT can be rejected for a laundry list of reasons, one of which is that it does not even depict anything like a physical narrative taking place in a 'world'. QFT is so alien to human intuition about the physical universe, that the very act of taking its equations seriously as a description of the universe leads to frightening conclusions. It is coy to describe QFT as being in discord with human intuition.
Nevertheless, QFT is the basis of the Standard Model of Particle Physics. THe standard model was so successful at predicting the forms that matter takes, that the nobel prizes could not be handed out quickly enough. The theory would predict a particle never seen , and years later a lab would produce that particle, often in the mass range predicted by the theory. QFT can barely be described as a 'science' (in the sense of bookkeeping) but the theory was so successful that it appears in history as a kind of naturalistic wizardry.
QFT can be used to create a prediction of the magnetic moment of the electron, starting from first principles, and working only on a chalkboard. The chalkboard number we might refer to as the theoretical prediction . The measurement of the electron's magnetic moment might be called the experimental value. The theoretical prediction matches the experimental value to 11 decimal places. That was the most accurate prediction by any science ever created by human civilization in all history.
Philosophers would never know this, since their discipline lacks experimental values.
While the above are anecdotes, the concluding message here is that modern physics has been wildly successful at predicting the behavior of matter and energy. Modern physics may even be said to be wildly successful at predicting the entire cosmos (a topic for a different article). But the attributes and ontological commitments that fit with these theories, in their plain theoretical form, are unpalatable to human philosophy. In the absence of evidence, philosophers could easily dispatch with these theories, justifiably claiming them as absurd.
This should raise serious questions regarding the utility about the sub-disciplines in philosophy called (1) metaphysics and (2) ontology . By the end of the 20th century, the idea that the world will conform itself to human intuition was no longer valid. Kant's epistemic rule-of-thumb that ideas are true in the degree they are in harmony with intuition was ultimately destroyed. Worse , in many cases, the ontology within the output of Kant, Heidegger, and Sartre extrapolate from the idea that the universe is a Laplacian machine, as was assumed in the Enlightenment. There is a danger that in talking about "Being" the reference is made to a type of intuitive ontology based around traditional substances. No one can worry about any mystery of Being, if the quandary itself is premised on notions of matter that are not factual in the actual universe we inhabit. Particles will tunnel through barriers by "teleporting" through them. The kinetic energy in a high-energy particle collision will convert into the mass of the constituent decay particles. One should not propose an important puzzle requiring philosophical inquiry, unless and until one first has all the evidence regarding it.
How will philosophers come to be aware of this evidence?
