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language as an analogy in the natural sciences
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language as an analogy in the natural sciences
The elucidation of molecular structure
Building a molecule
Mixing and combining
The lesson from science history
Combinatorial chemistry
Parallels with linguistics
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6. Parallels with linguistics

To provide a first instance, let's return to this daily activity of chemists, structural analysis. It translates, for the most part, in the "reading" of a document, known as a nuclear magnetic resonance spectrum. This consists of a series of lines, occurring at various frequencies in the microwave range (MHz). Looking at such an array of discrete peaks, the chemist identifies them and declares to himself: "This is a methyl group, this is a phenyl ring, this is a methyl ketone, this is an aldehyde", and so on. In other words, his brain recognizes semantic pointers, in very much the same way as we identify phonemes, syllables and words in the acoustic spectrum (30Hz - 30 kHz). Thus, reading from an nmr spectrum of a molecule the underlying structural elements exploits very similar cognitive skills as employed by the competent speaker of a language.

But the parallel is yet more general. To hear words when listening to speech - or likewise for the musician to hear notes when listening to sound vibrations extending in time - means a transformation by the neurones in the brain of a continuum, of a physical disturbance that varies continually with time, into a string of discrete signals.

Chemists constantly make similar transforms. Arguably the most important and implicit among these, they refer constantly to atoms in molecules: This aporia makes the assumption that, even though the electronic distribution has been altered, an oxygen atom (say) retains its identity in environments as diverse as a carbon dioxide CO2 molecule, a water H2O molecule, or an iron pentacarbonyl Fe(CO)5 molecule. Transferability, i.e. recognition of atoms and radicals in molecules, is basic to chemistry. It is a property shared with all natural languages, where the analog is the recognition of phonemes.

Let me turn to yet another parallel. Very often, in the course of the multistage synthesis of a complex molecule, that of a natural product typically, the chemist brings in an (aesthetic) element of surprise and elegance, by way of a deep-seated rearrangement. To give a schematic idea of what it consists of, and taking as an example a molecule presenting in sequence four modules A-X-Y-B, a rearrangement would turn it into X-A-B-Y, for instance. As such, rearrangements are a kind of molecular wordplay, such as in the anagram or in the pun.

The next point I'll make, for being brief nevertheless is arguably the most important. Chemistry and language share creativity, viz. the ability to bring into existence brand-new statements. Language allows us to flesh out our thoughts, on whatever topic or form. It enables us to express the poetry of the world, and to give a linguistic representation of any natural object. Chemistry allows us to make artificial species, to such an extent that mankind now lives in a chemisphere of its own devising. From hair to toe, we are covered with chemicals that we have invented.

At this point, I'll stop the parallel. I could go on and on about the deep-seated analogy between chemical science and linguistic science. For those of you interested in further comparisons, I have written a whole book, La parole des choses, to deal with this issue. You'll find in it many more examples and arguments in support of the same thesis.

There is a deep analogy between chemistry and linguistics, that can be elaborated on fruitfully quite far
Let me give a couple of examples.

All languages, a majority of which use syllables CVC consisting of a vowel V in-between two consonants C, have given themselves rules to exclude series of consecutive consonants, depending on their type and on their number. In the French language, for instance, sequences of three consonants are not rare, as in astronaute; apart of course of cases in which duplication through gemination occurs: with functional value in forms such as "courrais" or "mourrais". Still in the French language, the word with the greatest accumulation of successive consonants (which may have led to its premature disappearance, since it has become archaic) is dextre, with four consonants in a row. In other words, such as exprès or extrême the group of consonants bridges two syllables: [eks-trem]. An example in German would be the name Karlsruhe with four consonants bridging two adjacent syllables. Consider now this chemical analogy: with the exception of polymers, to a large extent derived from carbon chemistry, molecules, especially when they include atoms from the right of the periodic table, i.e. atoms that tend to be electron-rich, dislike bringing them together beyond a number of about three.

Take the oxygen atom as an example. Dioxygen, a relatively unstable molecule already, has two such atoms. The ozone molecule, with three oxygen atoms, is yet more reactive. It is capable, on account of this activation, of adding to ethylenic double bonds. The five-membered ring first formed , with three oxygens in a row, is so unstable that it rearranges spontaneously to an isomeric structure with one oxygen on one side, and a peroxo bridge on the other.

Let me provide a second example of the analogy and of its fruitfulness. A central phenomenon to chemistry is conjugation, that is to say the interaction between chemical groups due to electronic delocalization. A Michael acceptor such as, for instance, acrolein shows such conjugation between the carbonyl group and the ethylenic double bond. According to the circumstances of reagents and conditions, such a conjugated entity will either react as a whole and undergo 1,4-addition, or it will behave as the sum of its independent parts, and then undergo for instance 1,2-addition.

Languages show us rather similar phenomena with respect to syllabization. Where the French language says table, continually, the English language, because its phonologically deep structure is different, says table [teibl] in two syllables. Likewise, when we say [poepl] peuple, the English say it quite differently [pi:pl]. This interesting problem in syllabization is reflected in a German word such as haben [ha:bn].