The chemical doppelgänger: Why finding life on Mars is a philosophical problem

“ Scientists want to study Martian samples with powerful lab equipment on Earth to search for signs of ancient microbial life and to better understand the processes that have shaped the surface of Mars. Most of the samples will be rock; however, researchers also want to examine regolith – broken rock and dust – not only because of what it can teach us about geological processes and the environment on Mars, but also to mitigate some of the challenges astronauts will face on the Red Planet. ”

“ Yet what a world of difference between the two—between a rock and a tree, between a man and the soil he cultivates. Grant that the physical and the chemical forces are the same in both, yet they work to such different ends in each. In one case they are tending always to a deadlock, to the slumber of a static equilibrium; in the other they are ceaselessly striving to reach a state of dynamic activity—to build up a body that hangs forever [Pg 13] between a state of integration and disintegration. ”

“ Could we have foretold the future of any form of life from its remote beginnings? Would our mathematics and our chemistry have been of any avail in our dealing with such a problem? Biology is not in the same category with geology and astronomy. In the inorganic world, chemical affinity builds up and pulls down. It integrates the rocks and, under changed conditions, it disintegrates them. In the organic world chemical affinity is equally active, but it plays a subordinate part. It neither builds up nor pulls down. Vital activities, if we must shun the term "vital force," do both. ”

“ THE study of rock-structure is one of great interest to the geologist, and not only does it teach him the various materials of which any particular rock is built up, but it will often lead him to the knowledge of wonderful facts relating to its origin and past history, and will enable him to trace some of the many changes to which it may have been subjected during the lapse of time. ”

“ When we go beyond the sphere of the concrete, the experimental, the verifiable, only our philosophy can help us. The world within us, the world of psychic forces, is beyond the ken of science. It can analyze the living body, trace all its vital processes, resolve them into their mechanical and chemical equivalents, show us the parts played by the primary elements, the part played by the enzymes, or ferments, and the like, and yet it cannot tell us the secret of life—of that which makes organic chemistry so vastly different from inorganic. ”

“ Is biology to be interpreted in the same physical and chemical terms as geology? Are biophysics and geophysics one and the same? One may freely admit that there cannot be two kinds of physics, nor two kinds of chemistry—not one kind for a rock, and another kind for a tree, or a man. There are not two species of oxygen, nor two of carbon, nor two of hydrogen and nitrogen—one for living and one for dead matter. The water in the human body is precisely the same as the water that flows by in the creek or that comes down when it rains ”

“ They look upon the living body as only the sum of its physical and chemical activities; they do not seem to feel the need of accounting for life itself—for that something which confers vitality upon the heretofore non-vital elements. That there is new behavior, that there are new chemical compounds called organic,—tens of thousands of them not found in inorganic nature,—that there are new processes set up in aggregates of matter,—growth, assimilation, metabolism, reproduction, thought, emotion, science, civilization,—no one denies. ”

“ A living body is never in a state of chemical repose, but inorganic bodies usually are. Take away the organism and the environment remains essentially the same; take away the environment and the organism changes rapidly and perishes—it goes [Pg 186] back to the inorganic. Now, what keeps up the constant interchange—this seesaw? The environment is permanent; the organism is transient. The spray of the falls is permanent; the bow comes and goes. Life struggles to appropriate the environment ”

“ Does not the fitness of living things; the fact that they perform acts useful to themselves in an environment which is constantly shifting, and often very harsh; the fact that in general everything during development, during digestion, during any of the complicated chains of processes which we find, happens at the right time, in the right place, and to the proper extent; does not all this force us to believe that there is involved something more than mere chemistry and physics?—something, not consciousness necessarily, yet its analogue—a vital x? ”

“ Science is at home in discussing all the material manifestations of life—the parts played by colloids and ferments, by fluids and gases, and all the organic compounds, and by mechanical and chemical principles; it may analyze and tabulate all life processes, and show the living body as a most wonderful and complex piece of mechanism, but before the question of the origin of life itself it stands dumb, and, when speaking through such a man as Tyndall, it also stands humble and reverent. ”

“ NASA's Mars Exploration Rover Spirit took this panoramic camera image of the rock target named "Mazatzal" on sol 77 (March 22, 2004) . It is a close-up look at the rock face and the targets that will be brushed and ground by the rock abrasion tool in upcoming sols.
Mazatzal, like most rocks on Earth and Mars, has layers of material near its surface that provide clues about the history of the rock. Scientists believe that the top layer of Mazatzal is actually a coating of dust and possibly even salts. ”

“ Throughout the geological eras the Earth’s surface has been subjected to foldings and wrinklings, volcanic activity has been almost unceasing, and there is abundant evidence to show how the original characters of both igneous and sedimentary rocks may be entirely effaced by the operation of chemical and physical forces. ”

“ So general, deep-seated, and far-propagated an activity as that of volcanoes, can not assuredly have its source in chemical affinity, or in the mere contact of individual or merely locally distributed substances. Modern geognosy* rather seeks the cause of this activity in the increased temperature with the increase of depth at all degrees of latitude, in that powerful internal heat which our planet owes to its first solidification, its formation in the regions of space, and to the spherical contraction of p 237 matter revolving elliptically in a gaseous condition. ”

“ Where the changes go to the extreme point, rocks originally distinctly bedded probably may be so taken to pieces and made over that all traces of their stratification may be destroyed, all fossils obliterated, and the stone transformed into mica schist, or granite or other crystalline rock. It may be injected into the overlying strata in the form of dikes, or it may be blown forth into the air through volcanoes. ”

“ All the rocks are aerated. We know what trouble we have in driving the air from even the most compact rock of which we wish to obtain the density with precision. Since the different mineral masses become aerated while they are becoming moist, and consequently, while they are cooling, the atmospheric strata should undergo a progressive decrease. It is, therefore, natural that the atmosphere of Mars should be much thinner than that of the earth; and that is an excellent condition for the telescopic study of the planet. ”

“ Samples of the Martian atmosphere would be collected and analyzed for telltale radiation. Observer units would be flown over the planet, with instruments to locate atom-bomb plants and possibly uranium deposits. The rocket-launching bases would also come under close observation. We would try to learn how close the scientists were to escaping the pull of gravity. Since Mars’s gravity is much less than the earth’s, the Martians would not have so far to progress before succeeding in space travel. ”

“ Sir Thomas Browne said, over two hundred years ago, that in philosophy truth seemed double-faced, by which I fancy he meant that there was always more than one point of view of all great problems, often contradictory points of view, from which truth is revealed. In the following pages I am aware that two ideas, or principles, struggle in my mind for mastery. One is the idea of the super-mechanical and the super-chemical character of living things ”

“ All the difference between man, all that makes a man a man, and an ox an ox, is beyond the reach of any of your physico-chemical tests. By the same token the gulf that separates the organic from the inorganic is not within the power of science to disclose. The biochemist is bound to put life in the category of the material forces because his science can deal with no other. To him the word "vital" is a word merely, it stands for no reality, and the secret of life is merely a chemical reaction. ”

“ The cell is the parent of every living thing on the globe; and if it is unthinkable that the material and irrational forces of inert matter could produce it, then mechanics and chemistry must play second fiddle in all that whirl and dance of the atoms that make up life. And that is all the vitalists claim. The physico-chemical forces do play second fiddle; that inexplicable something that we call vitality dominates and leads them. ”

“ The living cell is a wonderful machine, but if we ask which is first, life or the cell, where are we? There is the synthetical reaction in the cell, and the analytical or splitting reaction—the organizing, and the disorganizing processes—what keeps up this seesaw and preserves the equilibrium? A life force, said the older scientists; only chemical laws, say the new. A prodigious change in the behavior of matter is wrought by life, and whether we say it is by chemical laws, or by a life force, the mystery remains. ”

“ We are pleased [Pg 226] when Nature imitates man, and we are pleased when man imitates Nature, and yet we recoil from the thought that life is only applied mechanics and chemistry. But the thought that it is mechanics and chemistry applied by something of which they as such, form no part, some agent or principle which we call vitality, is welcome to us. No machine we have ever made or seen can wind itself up, or has life, no chemical compound from the laboratories ever develops a bit of organic matter, and therefore we are disbelievers in the powers of these things. ”

“ We see the agents he names astronomic, geologic, meteorologic, having their effects upon inanimate objects as well, but they do not start the process of development in them; they change a stone, but do not transform it into an organism. The chemist can take the living body apart as surely as the watchmaker can take a watch apart, but he cannot put the parts together again so that life will reappear, as the watchmaker [Pg 241] can restore the time-keeping power of the watch. ”

“ If we say the particular essence of life is chemical, do we mean any more than that life is inseparable from chemical reactions?
After we have mastered the chemistry of life, laid bare all its processes, named all its transformations and transmutations, analyzed the living cell, seen the inorganic pass into the organic, and beheld chemical reaction, the chief priestess of this hidden rite, we shall have to ask ourselves, Is chemistry the creator of life, or does life create or use chemistry? ”

“ But the wheels in organic nature go around from something inside them, a kind of perpetual motion, or self-supplying power. They are not turned, they turn; they are not repaired, they repair. The nature of living things cannot be interpreted by the laws of mechanical and chemical things, though mechanics and chemistry play the visible, tangible part in them. If we must discard the notion of a vital force, we may, as Professor Hartog suggests, make use of the term "vital behavior."
Of course man tries everything by himself and his own standards. ”

“ The life of every organic individual is nothing but a connected chain of very complicated material phenomena of motion. These motions must be considered as changes in the position and combination of the molecules, that is, of the smallest particles of animated matter (of atoms placed together in the most varied manner) . The specific, definite tendency of these orderly, continuous, and inherent motions of life depends, in every organism, upon the chemical mingling of the albuminous generative matter to which it owes its origin. ”

“ The agents at work have been "variation"—that is to say, the response to the never-ceasing variation of the surrounding world or environment—and the survival in the struggle for existence of the fittest varieties so produced.
There is nothing surprising or extraordinary in the existence of variation. The conditions of life and growth are never absolutely identical in two individuals, and the wonder is not that species vary, but that they vary so little. The living substance of animals and plants is an extremely complex chemical substance, ever decomposing and ever being renewed. ”

“ His memoir, aside from its philosophical parts, is a comparative chart of organic biology and mineral biology, and shows that all the branches of studies relating to organic beings can also be applied to minerals.
He begins by defining life as the state of integration of matter when it, departing from the simply molecular condition, arrives at the state of forming complex groups of determined chemical and physical structure, and becomes capable of reacting upon the ambient medium in such a way as to assimilate to itself the elements peculiarly suitable to it. ”

“ Life, says Verworn, is like fire, and "is a phenomenon of nature which appears as soon as the complex of its conditions is fulfilled." We can easily produce fire by mechanical and chemical means, but not life. Fire is a chemical process, it is rapid oxidation, and oxidation is a disintegrating process, while life is an integrating process, or a balance maintained between the two by what we call the vital force. Life is evidently a much higher form of molecular activity than combustion. ”

“ If it does so come, and when it does so come, this will not prove that life is a less noble and less wonderful thing than we thought. It will only prove that chemistry and physics are more noble and more wonderful than we dreamed.
There is another way of approaching this life problem, though it seems to be rather a begging of the question than a solution of it. Of recent years it has been discovered that even the very low temperatures obtained by evaporating liquid air, say three hundred degrees below zero, Fahrenheit, do not kill seeds or spores of mold. ”

“ To regard life as of non-natural origin puts it beyond the sphere of legitimate inquiry; to look upon it as of natural origin, or as bound in a chain of chemical sequences, as so many late biochemists do, is still to put it where our science cannot unlock the mystery. ”

“ And herein we get a glimpse of the magic of chemical combinations. That mysterious property in matter which we call chemical affinity, a property beside which human affinities and passions are tame and inconstant affairs, is the architect of the universe. ”

“ The physicist tends to interpret everything by mechanical action and reaction; the chemist lays more particular stress on the chemical properties of organic as of inorganic matter; the physiologist emphasizes cellular structure and combination, and makes much of brain cells, the spinal cord, the nervus sympathicus, and the [Pg 324] special sense-organs; the biologist often regards the attraction and repulsion involved in the so-called sensibility of all forms of living matter as the cause of all life phenomena ”

“ We have a good illustration of the power of chemistry, and how closely it is dogging the footsteps of life, in the many organic compounds it has built up out of the elements, such as sugar, starch, indigo, camphor, rubber, and so forth, all of which used to be looked upon as impossible aside from life-processes. ”

“ While we read with pleasure that he is “not prepared to concede that we have in chemical and physical processes the whole secret of organic life,” we note with a still greater delight the following honest confession on his part: “Still we are, in many respects, approximating the phenomena of the organic world to those of the mineral kingdom ”

“ A higher mechanics, a higher [Pg 38] chemistry, if you prefer, a force, but a force differing in kind from the physical forces.
The forces of life are constructive forces, and work in a world of disintegrating or destructive forces which oppose them and which they overcome. The mechanical and the chemical forces of dead matter are the enemies of the forces of life till life overcomes and uses them; as much so as gravity, fire, frost, water are man's enemies till he has learned how to subdue and use them. ”

“ Vastly contributory to the understanding of organic beings as are chemico-physical investigations upon them, indeed impossible though it is to gain exhaustive knowledge of them in any aspect of their lives without such investigations, every truly vital chemico-physical problem of organisms is two phased: how do the chemico-physical attributes of the constituent substances act upon and so explain the organisms; and what particular structures and activities are the chemical substances caused to manifest by being constituents of and used by the particular organisms? ”