One perspective on this position is that of the founder of logical positivism, August Comte, that knowledge passes from the theological (“God did it”) to the metaphysical (“it is the result of poorly understood laws and processes, dictated by God or something like God”) to the “positive” (“it follows from these physical laws in this way”) as we learn more about it.  Thus the motions of the planets in the sky passed from arbitrary and dictated by the gods (the ancient Greek mythological perspective), to predictable but ultimately mysterious (Ptolemy, and even up to Kepler, though he tried hard at a physical explanation), to positive and predictable (Newton, with important modifications by Einstein and others like Yarkovsky).  (This isn’t precisely how Comte described things, but the general thrust is all I’m after here).

Science as a philosophy is logically positivist.  It assumes (and cannot prove or refute) that the universe is governed by Natural Law and treats as true only those assertions that can be empirically confirmed (or successfully avoid potential refutation).  This doesn’t mean that scientists are personally positivist, though:  most of us don’t bother debating the empirically proven benefits (within the limitations of our senses) versus costs of Folgers over Maxwell House before buying coffee grounds.  It’s not in human nature to be strictly positivist in our choice of romantic partners, or pets, or code of ethics, or political affiliation, and so on (although some may attempt to do this positivism has serious fundamental flaws as a philosophy, as do all philosophies).    

I have written about how some Big Questions have, amazingly, gone from essentially theological to positive in the span of the last century.  Cosmology has several of these feathers in its cap, as does exoplanetary astronomy, and, really, all of astrophysics.  The existence of planets around other stars was asserted by the heretic Giordano Bruno, who wrote:

There are countless suns and countless Earths all rotating around their suns in exactly the same way as the seven planets of our system. We see only the suns because they are the largest bodies and are luminous, but their planets remain invisible to us because they are smaller and non-luminous…….The countless worlds in the universe are no worse and no less inhabited than our Earth

This quote is a favorite among introductory astronomy instructors at the beginning of a unit on exoplanets.  Bruno is often called a martyr for science because he was burned at the stake for his heterodox views, but really his view was just as theological as its opposite (from a positivist perspective): he had no physical reason to believe this was true.  Today, we do: the topic has gone from unknowable to known.

But my point here isn’t that as we explore we learn the answers to questions that we didn’t have answers to, it’s that we learn answers to questions we thought were unanswerable.  I expect that some day we will know whether Mars ever had liquid water and where and for how long, and so on.  We may never know if there is other life in the Universe.  I suspect that we will never know how the universe began or the origin of all of the physical constants.  We will almost certainly never know the volume of the Universe to any precision (if we know it at all, we might determine that it’s infinite; maybe).  

Even Comte was wildly pessimistic about what was knowable.  He famously wrote:

Men will never compass in their conceptions the whole of the stars.

He based this on his assertions that:

…we need to know only what… acts upon us; and the influence which acts upon us becomes, in turn, our means of knowledge.  This is evidently and remarkably true in regard to Astronomy.  It is of the highest importance to us to know the laws of the solar system: and we have attained great precision with regard to them; but, if the knowledge of the starry universe is forbidden to us, it is clear that it is of no real consequence to us, except as gratification of our curiosity…  

and

We may see at a glance that astronomy is independent of all the natural sciences, depending on Mathematics alone… Philosophically speaking, astronomy depends on Mathematics alone, owing nothing to Physics or Chemistry…

Oops!  Within Comte’s own lifetime Kirchhoff, Bunsen and Fraunhofer would discover the chemical composition of the solar atmosphere and of the stars, and in the 20th century Cecelia Payne-Gaposchkin would explain their chemistry and put stellar astronomy on a quantitative physical basis (in what Otto Struve would call “undoubtedly the most brilliant Ph.D. thesis ever written in astronomy.”)  Astrophysics was born.  

Today, it’s fashionable and snarky to put string theory into the same category Comte put astronomy into (I’m guilty of this, and will continue to be), but who knows when some cosmological or particle physicist will produce some data that can fantastically validates their work?  Maybe tomorrow;  maybe never.  It’s hard to say (maybe impossible!).  

Outside of astronomy, one of the biggest transitions from theological to metaphysical, and, recently and tentatively, into positive, is that of the origin of consciousness.  My thinking on the topic was profoundly influenced when I was younger by Douglas Hofstadter’s G�del, Escher, Bach: An Eternal Golden Braid, a Pulitzer-Prize-winning masterpiece tying artificial intelligence, infinite recursion, fables, logic, and music into an exploration into the logical and physical origins of the conscious mind.  This is an important topic, since it directly informs our morals and politics, especially on topics like animal rights, food policy, and abortion, and one where philosophers, ethicists, and theologians are being forced to make room at the table for cognitive scientists and other scientists.

An excellent summary of some of the latest developments in this field, sort of an executive summary of a recent book, the Ravenous Brain (which I have not read) by its author, Daniel Bor, appeared in a recent article in Slate.  Read it;  this is an area where I am constantly amazed to learn that something I always assumed was forever beyond the reach of science might have already fallen into its domain.  The implications are profound, and I have not adjusted to them yet.

[images of Comte and Payne-Gaposchkin from Wikipedia]