My dear Mr Darwin
I have to thank you for a copy of your book on the `Origin of Species’. You will easily believe that it has interested me very much, and probably you will not be surprized to be told that I cannot, yet at least, become a convert to your doctrines. But there is so much of thought and of fact in what you have written that it is not to be contradicted without careful selection of the ground and manner of the dissent, which I have not now time for. I must therefore content myself with thanking you for your kindness.
believe me | Yours very truly | W Whewell
Darwin showed the note to Charles Lyell with the comment, "Possibly you might like to see enclosed note from Whewell, merely as showing that he is not horrified with us." And this is quite right. As Darwin surely recognized, despite Whewell's disagreement, the letter is quite complimentary. It's easy to miss this. Someone who doesn't know anything about Whewell's philosophy of science might read "there is so much of thought and of fact in what you have written" as a vague and noncommittal description, and therefore read Whewell's claim that he doesn't have the time to give his objections as a claim that Whewell can't respond because Darwin has written too much to make a short response easily. But what Whewell is actually saying, despite his disagreement with Darwin's conclusions, is that Darwin's argument is scientifically excellent, and thus that any objection would have to be carefully developed to be of correspondingly good quality. 'Thought' and 'Fact' are not vague colloquial terms for Whewell; they are at the very heart of his view of the scientific enterprise.
The foundation of much of Whewell's philosophical account of the sciences is what he calls the 'fundamental antithesis of philosophy'. This fundamental antithesis he regards as widely recognized, although people use different terms to characterize it. On one side of the antithesis people use terms like:
For the other side of the antithesis people use terms like:
Contingent or Experiential Truths
Whewell doesn't think that these terms on each side are synonymous, but he does think that they bring out two different sides that are found in all human knowledge. All human knowledge is a sort of union of mind and world, and we can never get away from the fact that knowing anything requires the mind to give an organization to some kind of information about the world.
It is important to repeat again that Whewell doesn't regard the terms in each list as synonymous. In fact he is quite clear that you cannot have 'Facts' unless you are already combining Thoughts and Things; and 'Theories' in Whewell's sense are themselves generalized Experiential Truths. This ties in with another feature of Whewell's view of the fundamental antithesis: while it is always there, the line between the two sides moves, and in any given case the distinction between the two sides of the antithesis can be quite subtle. The moment we start experiencing things we also start organzing our experiences in thought; we never theorize in complete absence of facts, and we never identify facts in complete absence of theory. From the earliest we can trace, our understanding of the world involves both sides of the antithesis, sometimes in complex ways, because understanding the world is itself the union, the synthesis, of both sides. When we use the terms on the list we are usually looking at a very specific aspect of this synthesis, and thus drawing out something that's a bit different from what we would draw out using other terms; this is why Whewell can claim both that the terms on each list are not synonymous and that each list has special relevance to one side of the fundamental antithesis.
It's the idea that knowledge is the synthesis of an antithesis that gives Whewell the German flavor for which many of his British contemporaries had no taste. But Whewell thinks that it is precisely this that is important: Thought and Thing, Theory and Fact, are inseparable:
In a Fact, the Ideas are applied so readily and familiarly, and incorporated with the sensations so entirely, that we do not see them, we see through them....And thus, a true Theory is a Fact ; a Fact is a familiar Theory. That which is a Fact under one aspect, is a Theory under another. The most recondite Theories when firmly established are Facts: the simplest Facts involve something of the nature of Theory. (PIS (1847) Volume I, p. 40)
Consider, for instance, the movement of a needle toward a magnet. We say that the magnet attracts the needle, that there is an attractive force involved or (to use terminology that only developed after Whewell's basic ideas were developed) a magnetic field. But these things are not simply given to sensation: we are applying ideas -- attraction, force, field -- to our sensations, while barely noticing that we are doing so. We are interpreting our sensations in order to make sense of them, and without this interpretation we don't have any clue what's going on. Even recognizing that time is passing, or that something is bigger or smaller than something else, requires this act of interpretation, this application of idea to sensory information. And this is why we have to think of the line between the two as in some sense moving. Applications of ideas to facts themselves get subject to more ideas, relative to which they are facts. Theories get confirmed and contribute to the discovery of new Facts, often Facts whose discovery depended crucially on the Theory.
It is this very point that Whewell regards as the foundation for scientific progress. Our Ideas become more general, new kinds of Experiential Truths are discovered; what is mostly Theory in one age has become Fact for another, to be organized by an even higher-order Theory. The Ptolemaic system of Hipparchus and Ptolemy organizes a wide number of astronomical facts; over the centuries new facts that are difficult to organize with the system become known; people look for systems capable of covering this broader range of facts in an adequate way, argue over the various merits and demerits of different systems, and eventually the Keplerian system wins out as a theory. Newton takes the Keplerian system as part of the factual terrain for a more general theory of mechanical motion; indeed, Newton's greatness on Whewell's view does not consist in any one of his discoveries but in the fact that Newton completes as one person a series of successive generalizations of ideas and expansions of factual territory what normally would take several. Ideas lead to more powerful Ideas; Facts lead to more general Facts. Again, Sylvius gives an interpretation of the phenomena that occur when acid and base are brought together, which is the theory that one neutralizes the other, which becomes established enough to be treated as a fact; this fact with many others is combined by later scientists under a basic theory of affinity or elective attraction; this is combined with other facts to get more general theories of affinity; this is combined with other facts to get atomic theory; and so forth. Putting it this way makes it sound more linear than it is -- while he thinks that the ascent is in some sense constant, Whewell is well aware that scientific progress is not in a straight line, that it branches and sometimes partly doubles back on reaching dead ends -- but gives the general idea. Whewell thinks that the progress of science is encoded in this way in technical terms: our best definitions of technical terms are as it were brief summaries of how ideas apply to the world in our best theories.
There is much more that could be said on this subject. Whewell has to argue at length that his account doesn't imply that everything we call knowledge is merely a subjective arrangement of sensory facts, but a real discovery of real truths about the world. He also has an interesting account, based on the fundamental antithesis idea, of the interplay between necessary truths and empirical experiments, and, of course, he goes on at length to discuss how different Ideas in each science organize Facts in more and more powerful ways. But this is enough to get the general idea of Whewell's account, and to see in what sense Whewell's letter is cautiously complimentary. When he says that Darwin's book has "so much of thought and of fact" that any objection would have to be very carefully thought out, he's saying that, right or wrong, the book is a truly scientific contribution to progress on the subject. Being full of thought and fact is what a good scientist does on Whewell's account. Whewell, who would die six years after the above letter, would never be convinced by Darwin's argument. But in this letter he is in fact claiming that it's a powerful argument that really does contribute to the scientific discussion. And as a first reaction, I think one could regard that as quite favorable; among compliments that a scientist can receive, there are very few that are better.