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Philosophy of Science and 'Certainty'


pearson, hempel, goodman, kuhn, feyerabend

Can we have certainty in the statements we make about the natural world?


From the early part of the twentieth century to the publishing of Kuhn's The Structure of Scientific Revolutions the history and philosophy of science this term seems to be a movement from absolute certainty, to probable certainty, to relative certainty .

Absolute certainty seems to be best illustrated by Karl Pearson. He states that “there is no short cut to truth, no way to gain a knowledge of the universe except through the gateway of scientific method (20 Pearson).” Thus, for Pearson, science’s certainty is guaranteed by its unique method. The problem with assuming that science’s method (which is uniquely objective) guarantees its certainty, is in defining just what that method is.

Pearson describes scientific method as objective because its practitioners are unbiased by any social prejudices. They simply collect facts, without preconceived notions of what those facts may tell us. From these objectively collected facts we infer irrefutable theories.

There are obvious (and numerous) problems with this description of scientific method. Even ignoring the notion of the unbiased scientist (which has been shown to be patently false on a number of occasions...Lysenko and the Tuskegee Syphillis experiments being the most obvious examples...) there are still problems with the unbiased collection of facts. Karl Hempel lays out the problems with Pearson’s simplistic view of scientific method rather well. Since you cannot collect all the facts, you have to decide which facts are relevant to your particular purpose. Thus, you cannot collect facts without already having a hypothesis about what counts as relevant. And then there is always the problem of induction (how we get from empirical facts to general theories). Thus, neither fact collecting nor theory inference are objective, and cannot guarantee certainty.

So Hempel reformulates what scientific method is. He sees all the collection of facts and the induction of theories as preliminary, non-scientific events. The real ‘science’ does not begin until we have a testable rule. How we get this rule, be it from objectively collected facts, or the dreams of a madman, does not matter. The guarantor of scientific certainty is in the process of testing these rules, which is a process of refuting and confirming theories through a variety of tests, and accepting the one that results at the end. Nelson Goodman states that, though we can have a refuted theory, which we know is not certain, we can never have absolute certainty of any particular theory. All we can have is probable certainty. This is a result of the fact that we can never fully confirm a theory (because that would mean we had absolute knowledge with which to compare it with and say that it corresponded with) but we can have theories that are more or less highly confirmed.

There are, however, problems with the notion of confirmation. Most importantly, in order to confirm (or ‘probably’ confirm) a theory, we have to appeal to something external to that theory. For science, this is the external world. It seems to me that an appeal of this sort assumes that we are not limited by any particular worldview and have direct access to the real world. This seems to beg the question. If we are attempting to confirm a theory about the real world, we cannot simply look at the real world and say whether that theory measures up to it or not. If we could, then we would already have a comprehensive theory of the real world and wouldn’t have to bother confirming other ones! Thus, scientific certainty cannot be based on confirmation (or, for that matter, falsification), whether it is probabilistic or absolute.

The relativistic view of scientific certainty proposed by Thomas Kuhn and Paul Feyerabend seems (yet again) more coherent to me. They agree that scientific certainty is possible, but not about the real world. Science is certain only to itself. Within the particular paradigm/worldview/epistemological system of science, any given statement can be absolutely confirmed. We can determine with certainty the atomic weight of hydrogen within the practice of science. The problem lies when science tries to say that a particular battery of tests on a particular sample of gas says something about the entire universe over all eternity. For Kuhn and Feyerabend (and myself), the attempt to leap out of ones own view of the worldview and see the universe from a God’s eye view is impossible and unjustifiable.



The only reference I have handy is the Kuhn one (sorry):


Thomas Kuhn, The Structure of Scientific Revolutions (Chicago, University of Chicago Press, 1962) Third Edition: 1996.
The Goodman article I was thinking about is called "The New Riddle of Induction"
Hempel's book is called The Philosophy of Natural Science
For Feyerabend references see my node on Paul Feyerabend
Karl Pearson, The Grammar of Science, 1892. reference.

Other 'philosophy of science'-esque nodes:

Paul Feyerabend
Imre Lakatos
How Science Undergoes Changes of Theory
The Strong Programme
Thomas Kuhn
Normal Science
Logical Postivism
Philosophy of Science
Descriptive and Prescriptive Philosophy of Science
All Swans Are White

Tag Up!

Certainty about our scientific statements seems to be something we can depend on, if we believe popular scientific journals. It might be more accurate to say, however, that science is always certain at the moment; certainty is not something solid and continuous. We move from being certain about one thing to being certain about another and put our faith in what the moment holds; we adapt our beliefs as theories evolve. The fact that we do this calls the objectivity of science into question in a very serious way. Even as we see on television or in magazines that a new theory answers the mystery of "x" in an indisputable manner, we forget that one hundred years in the past, our progenitors were saying and believing the same thing about another theory. So, certainty through scientific method becomes sketchy at best, there is always a new discovery around the corner that will throw us for a loop and change our minds.

I think that certainty can be achieved just as well through spirituality or other methods outside scientific ones. It is because most mainstream science relies on falsification that it can never be entirely certain. Indeed, its focus is on what is uncertain and anomalous. Science seems to be more about making statements that seem to be the most reasonable given what it has to work with than it is about making (true) essentialist declarations. Prescientific experience, on the other hand, affords us more certainty about the world, because it does not continually prescribe new theories to us (take two Bohr's atoms and call me in the morning). It allows us to develop our own epistemological framework, one which is consistent and satisfying to us as individuals. We know that the sun rises and the sun sets, and that rain helps plants grow, and so on. As science develops, we expand our theories to say that, for instance, the sun revolves around the earth, and then that the earth revolves around the sun. This shows that science can reach a point at which we are certain enough to leave research in that area at a standstill; however, the more we try to figure out, the more we are left with questions.

Paul Feyerabend attacks the certainty of the scientific method, saying that it is more or less tyrannical and appoints legitimacy to itself because it says it is legitimate! The propositions we make about the natural world are only as certain as we are about our methodology. If we have constructed a way of looking at the world that demands uncertainty to achieve truth, then our statements are always subject to change. If, on the other hand, our perspective is complete and satisfying to us, then we can be certain. In other words, certainty is not an objective thing. Truth only becomes truth when we take measures to show that it is true! When we rank science as an ideology alongside other ideologies, one that is not priveliged over any other, we can see that this is not an entirely off-the-wall statement to make. Even though it is given considerable credibility in our society the scientific world view is one we can choose to take up or keep at a distance. Science is not the only path to certainty about our world*.


*That certainly sounds like a dogmatic assertion - but I'm telling you it's not!


As my partner in noding indicated, some philosophers of science to check out include Paul Feyerabend, Imre Lakatos, and guys like that. Also, Bruno Latour is the man.

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