by Judith Curry

With this method the dangers of parental affection for a favorite theory can be circumvented. – T.C. Chamberlin

In a remarkable interview, Presidential candidate Jeb Bush made the following statements about climate change:

As he has before, Bush acknowledged “the climate is changing” but stressed that it’s unknown why. “I don’t think the science is clear of what percentage is man-made and what percentage is natural. It’s convoluted,” he said at a house party in Bedford, New Hampshire.

“For the people to say the science is decided on this is really arrogant, to be honest with you,” he continued. “It’s this intellectual arrogance that now you can’t have a conversation about it, even. The climate is changing. We need to adapt to that reality.”

Jeb gets it exactly right. There are two broad hypotheses for recent climate change: human causes and natural causes (with numerous sub-hypotheses contained within). The climate debate is dominated by the premature carving in stone of a theory that humans are the dominant cause of recent climate change.

Clyde Spencer has brought to my attention a remarkable essay published by geologist T.C. Chamberlin: The method of multiple working hypotheses, first published in 1897 and re-published in Science in 1965. This is an amazingly eloquent and insightful essay that provides some important insights into the scientific debate on climate change, and addresses the concerns raised by Jeb Bush. Excerpts:

There are two fundamental classes of study. The one consists in attempting to follow by close imitation the processes of previous thinkers, or to acquire by memorizing the results of their investigations. It is merely secondary, imitative, or acquisitive study. The other class is primary or creative study. In it the effort is to think independently, or at least individually, in the endeavor to discover new truth, or to make new combinations of truth, or at least to develop an individualized aggregation of truth.

JC comment: this illustrates the consensual versus dissension theories of scientific inquiry, discussed in my paper No consensus on consensus.

Premature theories

The habit of precipitate explanation leads rapidly on to the development of tentative theories. For a time the theory is likely to be held in a tentative way with a measure of candor. With this tentative spirit and measurable candor, the mind satisfies its moral sense, and deceives itself with the thought that it is proceeding cautiously and impartially toward the goal of ultimate truth. It fails to recognize that no amount of provisional holding of a theory, so long as the view is limited and the investigation partial, justifies an ultimate conviction.

JC comment: the time of the IPCC FAR (circa 1990) reflects this state, with a relatively tentative spirit and a measure of candor.

It is in this tentative stage that the affections enter with their blinding influence. Love was long since represented as blind, and what is true in the personal realm is measurably true in the intellectual realm. Important as the intellectual affections are as stimuli and as rewards, they are nevertheless dangerous factors, which menace the integrity of the intellectual processes. The moment one has offered an original explanation for a phenomenon which seems satisfactory, that moment affection for his intellectual child springs into existence; and as the explanation grows into a definite theory, his parental affections cluster about his intellectual offspring, and it grows more and more dear to him, so that, while he holds it seemingly tentative, it is still lovingly tentative, and not impartially tentative.

JC comment: By the time of the IPCC SAR (circa 1995), not only did ‘parental affection’ set in, but the whole issue became politicized in Madrid, with the political need to find at least ‘discernible’ evidence of a human cause for warming.

So soon as this parental affection takes possession of the mind, there is a rapid passage to the adoption of the theory. There is an unconscious selection and magnifying of the phenomena that fall into harmony with the theory and support it, and an unconscious neglect of those that fail of coincidence. The mind lingers with pleasure upon the facts that fall happily into the embrace of the theory, and feels a natural coldness toward those that seem refractory. There springs up, also, an unconscious pressing of the theory to make it fit the facts, and a pressing of the facts to make them fit the theory. When these biasing tendencies set in, the mind rapidly degenerates into the partiality of paternalism. The search for facts, the observation of phenomena and their interpretation, are all dominated by affection for the favored theory until it appears to its author or its advocate to have been overwhelmingly established.

JC comment: Written well over a century ago, this describes current climate science to a T.

The theory then rapidly rises to the ruling position, and investigation, observation, and interpretation are controlled and directed by it. From an unduly favored child, it readily becomes master, and leads its author whithersoever it will. The subsequent history of that mind in respect to that theme is but the progressive dominance of a ruling idea.

JC comment: Government research funding, journal editorial practices and professional recognition related to climate research are all working in the direction to control research to support the theory of human caused climate change.

Briefly summed up, the evolution is this: a premature explanation passes into a tentative theory, then into an adopted theory, and then into a ruling theory. When the last stage has been reached, unless the theory happens, perchance, to be the true one, all hope of the best results is gone. To be sure, truth may be brought forth by an investigator dominated by a false ruling idea. His very errors may indeed stimulate investigation on the part of others. But the condition is an unfortunate one. Dust and chaff are mingled with the grain in what should be a winnowing process.

JC comment: In the case of climate change, this argues for industry funding of more diverse perspectives, given the bias introduced by politicization and federal funding.

A family of hypotheses

The working hypothesis differs from the ruling theory in that it is used as a means of determining facts, and has for its chief function the suggestion of lines of inquiry; the inquiry being made, not for the sake of the hypothesis, but for the sake of facts. Under the method of the ruling theory, the stimulus was directed to the finding of facts for the support of the theory. Under the working hypothesis, the facts are sought for the purpose of ultimate induction and demonstration, the hypothesis being but a means for the more ready development of facts and of their relations, and the arrangement and preservation of material for the final induction.

The method of multiple working hypotheses idiffers from the former method in the multiple character of its genetic conceptions and of its tentative interpretations. It is directed against the radical defect of the two other methods; namely, the partiality of intellectual parentage. The effort is to bring up into view every rational explanation of new phenomena, and to develop every tenable hypothesis respecting their cause and history. The investigator thus becomes the parent of a family of hypotheses: and, by his parental relation to all, he is forbidden to fasten his affections unduly upon any one. In the nature of the case, the danger that springs from affection is counteracted, and therein is a radical difference between this method and the two preceding. The investigator at the outset puts himself in cordial sympathy and itn parental relations (of adoption, if not of authorship) with every hypothesis that is at all applicable to the case under investigation. Having thus neutralized the partialities of his emotional nature, he proceeds with a certain natural and enforced erectness of mental attitude to the investigation, knowing well that some of his intellectual children will die before maturity, yet feeling that several of them may survive the results of final investigation, since it is often the outcome of inquiry that several causes are found to be involved instead of a single one.

JC comment: It should be obvious that climate change has multiple causes, although the political definition of climate change has attempted to define natural causes of climate change out of existence.

The true explanation is therefore necessarily complex. Such complex explanations of phenomena are specially encouraged by the method of multiple hypotheses, and constitute one of its chief merits. We are so prone to attribute a phenomenon to a single cause, that, when we find an agency present, we are liable to rest satisfied therewith, and fail to recognize that it is but one factor, and perchance a minor factor, in the accomplishment of the total result.

JC comment: BINGO

A special merit of the method is, that by its very nature it promotes thoroughness. The value of a working hypothesis lies largely in its suggestiveness of lines of inquiry that might otherwise be overlooked. Facts that are trivial in themselves are brought into significance by their bearings upon the hypothesis, and by their causal indications. But a single working hypothesis may lead investigation along a given line to the neglect of others equally important; and thus, while inquiry is promoted in certain quarters, the investigation lacks in completeness. But if all rational hypotheses relating to a subject are worked co-equally, thoroughness is the presumptive result. In the use of the multiple method, the re-action of one hypothesis upon another tends to amplify the recognized scope of each, and their mutual conflicts whet the discriminative edge of each. The analytic process, the development and demonstration of criteria, and the sharpening of discrimination, receive powerful impulse from the co-ordinate working of several hypotheses. Fertility in processes is also the natural outcome of the method. Each hypothesis suggests its own criteria, its own means of proof, its own methods of developing the truth; and if a group of hypotheses encompass the subject on all sides, the total outcome of means and of methods is full and rich.

JC comment: I can’t imagine stating it any better than this.

Imperfections of knowledge

The imperfections of our knowledge are more likely to be detected, for there will be less confidence in its completeness in proportion as there is a broad comprehension of the possibilities of varied action, under similar circumstances and with similar appearances. So, also, the imperfections of evidence as to the motives and purposes inspiring the action will become more discernible in proportion to the fulness of our conception of what the evidence should be to distinguish between action from the one or the other of possible motives. The necessary result will be a less disposition to reach conclusions upon imperfect grounds. So, also, there will be a less inclination to misapply evidence; for, several constructions being definitely in mind, the indices of the one motive are less liable to be mistaken for the indices of another.

The total outcome is greater care in ascertaining the facts, and greater discrimination and caution in drawing conclusions. The remedy lies in correct intellectual habits, in a predominant, ever-present disposition to see things as they are, and to judge them in the full light of an unbiased weighing of evidence applied to all possible constructions, accompanied by a withholding of judgment when the evidence is insufficient to justify conclusions.

JC comment: Mr. T is well pleased.

JC reflections

It’s hard to imagine that I’ve never before come across Chamberlin’s essay; it seems that it has been published a number of times (most recently 1965). I recommend that you read the entire essay, it is a classic.

The implications for climate change research are profound. Not only is there arguably at least two meta-hypotheses for recent climate change [link], but the sub-hypotheses within each meta hypothesis illustrates the complexity of the causes of climate change, which are not easily separable. By considering all of the causes of climate change, our interpretations of evidence is enriched and so our understanding. The climate change issue is complicated in a manner unforeseen by Chamberlin — political preference for one particular theory that torques the direction of the research through funding.

Returning to Jeb Bush’s statement, it clearly recognized that both natural and human causes contributed to climate change, these causes are convoluted with one another, and there is no agreement as to what percentage is man-made and what percentage is natural. While the IPCC says more than half is human caused (not very precise), but its not clear what this even means [link] in terms of Bush’s question as to what percentage is man-made versus natural.