Scientific method. If we’re not engaging in self-deception, trying to ad hoc our way across the bridge from logical possibility to the actual truth of a matter, we see that we have a variety of genuinely objective tools ready-to-hand to help us reach warranted belief (logical possibility; the three rules of thought; deduction, induction, and abduction; and Occam’s razor). These are all brought together in scientific method. The scientific method is a process by which one: (1) brings questions to the cosmos (“Why are there so many species of organisms on our planet?”); (2) generates competing theses or theories about it that are capable of falsification (evolution by natural selection versus, say, evolution by the intervention of space aliens who introduce new organisms from their space ship once every ten million years); (3) tests those theories (if natural selection is true, we should see transitional organisms in the fossil record; if alien intervention is true, we should see a marked shift of organisms in the fossil record only once every ten million years or so, and with no intermediate fossils of any sort); and (4) incorporates the best of those theories into a coherent network of other best theories (the biologist’s theory of evolution by natural selection, being the best theory of the two above, should slot coherently into the geologist’s best theory as to the age of the Earth).
Survival of the fittest theories. So scientific method is a sorting process; it’s about discovering survivors after an ordeal of testing, whether in or out of the lab. It’s about the survival, as it were, of the fittest theories (models, maps for navigating reality). These fittest theories are discovered in the way that the best gladiators in the ancient Roman arenas were discovered: by contrivances dreamed up for trial or testing. But in the case of science, these trials are not dreamed up by emperors, but by scientists–scientists deploying scientific method.
Criteria of adequacy. Aside from a theory being testable (a theory that cannot be falsified, or is phrased in such a way that it’s impervious to new data, reality testing, or competition from competing theories is not a scientific theory), by what general criteria is it to be judged in relation to other theories? First, if it’s an interesting theory, scientists agree that is must be fruitful (it makes predictions that pan out; it’s not readily surprised by new data, constantly requiring the addition of ad hoc premises to save it). Second, it has scope (it explains a lot of things, not just, say, one or two things). Third, it slots into our already well-established background knowledge (a theory of biology shouldn’t contradict a well-established theory of physics). Fourth, it’s simple (it doesn’t multiply premises beyond necessity; it incorporates new data in a natural, as opposed to a strained, way). These four, plus testing, can be posed as straightforward questions brought to a theory: Is it testable? Is it fruitful? Does it have scope? Does it accord with our well-established background knowledge? Is it simple? These questions, together, are sometimes called by scientists the criteria of adequacy.
Abduction: reasoning to the best hypothesis. But it’s not enough to be adequate. Even if a theory passes through these five questions with flying colors, it still has to survive the judgment of the sixth and final criterion: Is it the best theory? It can’t be merely a good, interesting, or adequate theory. It needs to be the very best on offer. Isaac Newton’s theory of gravity works, but Albert Einstein’s has greater scope, and so works better. (Sorry, Isaac.) And perhaps someday a better theory of gravity will arrive, overthrowing Einstein’s. Scientific knowledge is always provisional. Galileo’s telescope never comes down.
Fact-value entanglement. In one sense, when working with scientific method, we’re not dealing with values, but facts. Noticing, for instance, that evolution entails competition (a fact) doesn’t tell you whether you should be competitive or cooperative with someone at work (a value). No is demands an ought. It was the philosopher and historian David Hume who first made this important is-ought distinction. But while it is often crucial to maintain this is-ought distinction in reasoning (noticing when one is pointing to a fact—an is—and a value—an ought)—it should also be observed that is and ought are difficult, arguably even impossible, in practice to wholly disentangle. Think, for instance, on the six criteria scientists broadly agree should be deployed to reach the truth of matters, and to lock-down things we can take to be facts. A good theory: (1) should be testable (2) should be fruitful; (3) should have scope; (4) should slot into our already well-established scientific background knowledge; (5) should be simple; and (6) should be the best theory on offer.
But notice all the shoulds in this list. In other words, our criteria for arriving at a thing we take to be a fact are value-laden. If, for example, we value the criteria of adequacy, then evolution is vastly more reasonable than alien intervention in explaining the variety of species on our planet. But why should the truth be a matter readily testable? Why do we value fruitfulness, scope, and coherence? Why should the things we take to be facts be simple, possessing an economy of premises, rather than elaborate and complex, possessing a multiplication of premises? Isn’t it obvious that there are many things that we take to be true that fail to meet one or more of the criteria or adequacy? And so, even if we are convinced that we have adopted the best values and models for generally getting at the truth of matters, we cannot wholly disentangle the processes we have chosen to get at the facts from the facts themselves. The criteria we value for bringing us to confidence that we’ve reached the truth cannot, like a ladder, be kicked to the ground after reaching the roof. If we kick away the ladder, we lose our basis for certainty as to where we actually are. Our values and models condition and infect our facts. We never have a wholly objective, value-free, or unmediated relation to the truth or the good.
That other Pope meat. The human condition, it thus appears, is to strive to reason even as we often fail in reason. So it is that we dwell in uncertainties as best we can, as the poet Alexander Pope (1688-1744) observed:
Placed on this isthmus of a middle state,
A Being darkly wise, and rudely great:
With too much knowledge for the Sceptic side,
With too much weakness for the Stoic’s pride,
He hangs between; in doubt to act, or rest;
In doubt his Mind or Body to prefer;
Born but to die, and reasoning but to err;
Alike in ignorance, his reason such,
Whether he thinks too little, or too much:
Chaos of Thought and Passion, all confused;
Still by himself abused, or disabused;
Created half to rise, and half to fall;
Great Lord of all things, yet a prey to all;
Sole judge of Truth, in endless Error hurled:
The glory, jest, and riddle of the world!