Origins of science
We don’t know how long humans have thought scientifically. We do know that the ancient cultures of Babylon and Egypt recorded and analysed the motions of the Sun and stars as the way of predicting the seasons. The Babylonians counted in 60s, a much better number than 10 if you ever need to divide by 3, and we still use 60 for time and 360 for angles, the two measures you need for basic astronomy. The recently analysed Antikythera device shows the importance of this single science to ancient Greek civilisation: their most sophisticated mechanisms and mathematics by far were devoted to astronomical predictions.
The great eastern cultures of China, India, Persia and others were often centuries ahead of Europe, but I will stick to Western developments and dates, as I know them better.
In Europe, the Renaissance of art and culture in the 14th to 17th centuries led also to a scientific revolution. Leonardo da Vinci (1452 –1519) made detailed drawings of the natural world and human and other anatomy: careful and precise observation as the essential first step in science. He didn’t just observe, he investigated, and when this is done with care it becomes experiment. He carried out medical dissections. On phenomena now in the domain of physics, he made systematic studies of movement, including water flow and aerodynamics. He formulated scientific hypotheses, recognising that fossils high on mountains showed that they were once the sea bed.
Nicolaus Copernicus (1473 – 1543) challenged our Earth-centred view of the Universe by showing that mathematics is much simpler if the Earth and the four other known local planets orbited the Sun. As lens manufacture developed and telescopes improved, Galileo Galilei (1564 – 1642) in January 1610 observed the moons of Jupiter, providing powerful support for the Copernican view. If other planets have moons, too, the Earth becomes (scientifically) less special. As it became apparent that the orbits of planets were elliptical and not exactly circular, Johannes Kepler (1571 – 1630) provided the precise mathematics required.
Isaac Newton (1642 – 1727) simplified Kepler’s laws to an inverse square law of gravitational attraction, and had to devise an inelegant version of an entirely new mathematics, calculus, to do so. A by-product of this was the fundamental discovery that force is proportional to acceleration (F = ma), the equation that created the modern science of dynamics.
The nature of light has long been the subject of speculation and enquiry. The modern view, the duality model of light, is a muddled compromise and hardly a scientific model at all, as we see here, so its history may be important.
Newton believed light to be composed of corpuscles. This can explain reflection and even refraction, but this view was comprehensively defeated by a series of analyses that showed that wave light could explain the phenomenon of interference, something that particle models have never achieved.
Newton’s contemporary, Christiaan Huygens (1629 – 1695) devised a famous principle that each point on a wave can be understood as generating further waves, and he showed that the combined effect of these would be what we observe. This is known as Huygens’ construction. Thomas Young (1773 – 1829) demonstrated the diffraction of a shaft of light at a sharp edge and the interference effect created when light or another wave passes through a pair (or more) of openings. Augustin Fresnel (1788 – 1827) used Huygens’ insight to explain these phenomena mathematically, effectively establishing for the following century that light was a wave.
Science felt that it had the final answer, simply and elegantly that light is a wave. Logically, it must therefore have a medium in which that wave propagates, and this was variously termed the ether or aether. James Clerk Maxwell (1831 – 1879) analysed this same ether to create a hydrodynamic explanation of magnetism, and it was his belief in this medium that led him to the idea of displacement current, providing the additional term that made his equations of electromagnetism successful, where others had failed.
Maxwell is a key figure in the development of modern physics (here) and modifications to his hydrodynamic model are central to Esau James’ unified model of physics (here).
The nature of science, 1516-1900 and beyond
In the above sections, we see the development and application of a scientific method. Some of the elements of this have been diluted in modern physics, and so we need to be clear about the methodology and principles that have been successful beyond modern physics.
Science begins with observation and experiment, doing these systematically where possible. It constantly seeks to understand, and we need to be clear as to what this means, as it is different from a philosophical or religious understanding.
Science attempts always to reason logically and clearly, so as to expose ideas that are imprecise or inconsistent. Internal contradictions and inconsistencies are a powerful demonstration that a hypothesis or explanation has fundamental failings.
Most importantly, science seems to do much better when it provides explanations based on a belief that events have causes, and that causes have predictable effects. The philosophical basis for this belief is problematic, as we can never see how a cause produces an effect in full detail. Nevertheless, the methodology of causal reasoning has proved immensely powerful in science.
We see it in Copernicus’ insight: smaller bodies orbit larger ones, so is this indicative of a universal cause? Newton’s mathematical clarity encourages us to look for a universal mechanism of gravitation, a gravitational force that is inversely proportional to the square of the distance. Huygens and Fresnel believed that they had demonstrated how light works, and Maxwell hoped to do the same for electromagnetism, and we can see here and here how this failed.
But we also see the power of cause and effect reasoning, known also as determinism, in Darwin’s explanation for evolution in terms of natural selection, in Mendel’s prediction of genes as the means of inheritance, and in plate tectonics, where we are scientifically convinced of a mechanism deep within the Earth that we cannot observe.
The failure of causation
We will examine this in more detail here, as it provides an insight into the reasons why modern physics is such a mess, but causal explanation, the provision of a physical mechanism for physical phenomena, did fail in relation to electromagnetism, and it failed in terms of light also, when a background medium could not be found.
Other scientific methodology
Not the methodology of experiment and observation, but the methodology of theory.
Three principles have been established over the centuries:
The principle of reductio ad absurdum (meaning reduction to the absurd) works as follows: if I start with a scientific hypothesis, and can use that to produce absurd conclusions, then the hypothesis itself is also absurd and hence false
Popperian falsifiability is the suggestion from Karl Popper (1902 – 1994) that a hypothesis is only scientific if it can in principle be falsified. It must therefore make predictions that have not yet been observed. This allows us (in principle) to avoid speculative ideas that might constrain our thinking but can never be checked
Theoretical methodology in modern physics
The key change in scientific theory within physics occurred from around 1900 onward. Determinist reasoning failed, and this failure was deemed to be permanent. The application of causal reasoning in physics was fundamentally undermined. In special relativity and gravitational theory it was deemed inappropriate. Quantum mechanics drifted into the metaphysical. Across modern physics its application became patchy and unreliable.
The additional principles of Occam’s razor, reductio ad absurdum and Popperian falsifiability have also become devalued in modern physics, most conspicuously in cosmology/astrophysics.
One of the most fascinating observations of modern physics is that a rigorous application of determinist reasoning is considered important in the rejection of the ether of Maxwell, but not important enough to apply it in evaluating the theories that arose from that rejection.
Outside of modern physics, the great theories of science tend to be causal and clear, allowing a sense of comprehension and an easy communication to the next generation. These are desirable attributes, but without knowing a lot more about science and the world we live in, we cannot claim them as essential for a valid scientific theory.
There may well be stuff that we don’t know and that is highly complex or very strange. There could be knowledge that is simply beyond us, but science history tells us that every time that we have come to that conclusion we have been wrong. These C-features of a theory such as natural selection or plate tectonics are highly beneficial, as they make it easy for all of us to check if the reasoning is valid, a facility that modern physics conspicuously lacks.
Causal reasoning from mechanism has a particular scientific benefit, as it provides steps in a chain of analysis that can be checked independently. This suggests an extension of simple falsifiability (yes/no) to evaluating theories based on how much falsifiability they have, and causal explanations have considerably more than any alternatives. If some falsifiability is good, then we cannot help but conclude that more is better.
Causal explanations are also the explanations that the scientifically inquisitive among us desire:
‘We cannot be satisfied with formulae that are merely placed side by side and agree only by a lucky chance; these formulae must, as it were, interlock. The mind will consent only when it sees reason for the agreement, and when this agreement even seems to be predictable.’ - Poincaréi.
One C-word that has been mostly implicit in the foregoing is the absolute requirement for consistency. That the best scientific theories tend to be causal, clear, comprehensible and communicable may be coincidental, but logical consistency is a more fundamental requirement.
If the duality ‘model’ for light lacks clarity, which it does, then it is suspect. If general relativity and quantum mechanics disagree, then at least one must be false in some respect. Since these disagreements are fundamental (see here), then at least one must be fundamentally flawed. We cannot claim to be scientific and come to a different conclusion.
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i. Henri Poincaré - The Dynamics of the Electron, Rend. Del Circ. Mat. Di Palermo 21 (1906) 129; translation in C.W. Kilmister, Special Theory of Relativity (Pergamon Press, 1970) page 145