One aim of this essay is to present Science in the one and only correct way that it can be presented, and so to dispel the faith some/many have that today’s Physics is a Science.
21C-Physics is the currently popular story whose too ambitious aim is to pin down the properties of the Universe in Laws that are independent of observers. Some Physicists hope that Physics can become a theory of everything. That objectivist aspiration is far beyond what humans are able to achieve. It is the fantasy that humans can know the story/mind of Reality, and I call it hubris.
The idea that 21C-Physics is a science is too vague. To correctly capture the empirical fact that Scientists over thousands of years have progressively noted empirical facts which have turned out to be useful for Humanity one needs to specify Science precisely. That requires the elaborately linked definitions, given below. Together those definitions specify the subjectivist Science which works where the objectivist Science professed by modern “Physicists” and modern “Philosophers” inescapably fails.
You are unable to explain Reality, of course, for the simple reason that your observations of Reality are limited to the place and the time in which you find your self. For some one else, like me, that is the same, but my place and my time — my changing now and my changeable here — are different from yours. Still it may be that you and I are close enough together to see ways to improve the stories we tell each other about the local aspects of Reality that we are able to think/talk about in the language we share. As to your particular story being correct (or mine) Reality itself is the only possible arbiter.
Reality allows you to grasp/share some of the many local stories of Reality that we call sciences. For you to grasp a particular science, you must tell it honestly to your self and others. Your stories will change, of course, as your private time moves inexorably forward, and as your location changes in ways that you are somewhat able to control. For you to understand this requires you to assimilate the linked definitions which follow. If this seems to be pedantic, that is only because our talk about Reality must be precise.
The simplest stories of Reality for you are the empirical facts, local to you, which you may repeatedly observe. Whenever you perform a particular action you see that “the same thing” happens. That is the same for me.
For example, any one may observe that the area of a triangle is invariant under movement of the triangle. More precisely: if, following Euclid, you employ ruler and compass to draw a copy elsewhere of a particular triangle you drew on a flat sheet and measure its area you find, inescapably, that the area of the copy equals the area of the original. That is a matter of fact which any who performs that action and honestly reports the result is compelled to accept.
With that, I am claiming a particular empirical fact about empirical facts. If you doubt it, show me a counter-example.
science (with a lower case “s”)
A science is a story of related empirical facts that are agreed by members of a community of individuals who have tested those facts and found no counter-examples. A science has two aspects, its mathematics and its physics, both essential/necessary, neither sufficient by itself. Example: graph theory, with graphs that you (and I) are able to prove theorems about as its mathematics, and the drawings you (and I) are able to make as its physics. Euler initiated that particular science, with his seven bridges of Königsburg.
Science is the Discipline which embraces your changing stories of how the Reality/Nature in which you find yourself works locally for you, and likewise for others, like me, who are nearby upon the Background surface. Science advances steadily, but with occasional great leaps made by great imaginations/minds. The creation/discovery of new stories with new rules/laws is sometimes/often key to the next great step.
Stories are the bearers of the meanings we give to what we see and what we say. Some story tellers anoint stories they like as theories, others as accounts, others as narratives, others as revelations. What distinguishes our many sciences is that they allow/require no value judgements: they accept that Reality is what it is.
Mathematics (with a capital “M”)
In this essay, this word, capitalised, stands for the discipline practiced by the people we call Mathematicians. A Mathematician tries to discover/prove theorems of one or more of the many independent formal stories/theories that I call a mathematics (lower case).
mathematics (with a lower case “m”)
Example: Euclidean geometry is a mathematics, and so is graph theory. Mathematics (with a capital M) includes both.
Physics (with a capital “P”)
In this book, this word, capitalised, stands for the discipline practiced by the people we call Physicists. The business of a Physicist is to subject to experimental test one or more of the many independent formal predictive stories that I call a physics (lower case).
physics [with a lower case “p”]
A physics [lower case!] is a story/theory of what is expected to happen locally, based on observation and testable by experiments.
Example: Ruler and compass drawings on a flat surface constitute the physics that can be done to test theorems of Euclidean Geometry.
Example: Planetary astronomy is a physics, and so is solid-state physics. Physics (with a capital P) includes both.
[This is very different from the widely accepted objectivist idea that Physics is what happens “objectively” as “time” passes.]
Science, so defined, is a way of thinking — a philosophy — which simply works. As will be evident to any one who carefully watches children, a child under the age of four instinctively thinks as a Scientist, trying out hypotheses/predictions about its local future, and favouring those which work. At age four, indoctrination by objectivist thinkers sets in, and the child is taught to conform, ostensibly by showing "empathy" and "social awareness".
Science, so defined, is the open-ended Story of Everything which some have hoped for. It works in the limited way that Reality allows/requires.