Guest EditorialDarwin's hypothesis on the origin of life invokes a primeval or primordial soup in water. This idea, and the very concept of evolution from the sea to more complex life, moving from sea inland, is not that of Darwin, but was originally formulated by the Greek philosopher Anaxagoras. Darwin's original contribution is the causal principle of natural selection. This is the main principle which drives evolution. The Darwinian primeval soup is a biochemical mix which led to biological primitive life. This is the idea of abiogenesis or geogenesis, which is of both biological and philosophical importance: life evolved from non-life, lifeless matter. So it is an evolution from biochemistry to biology. This occurred independently from the rest of the universe. Darwin did not say much or anything about extraterrestrial life. In the world view of his time, references to it did occur, but very seldom. It just did not come up, and would have been hailed as inappropriate. Jules Verne (1828-1905) a contemporary of Darwin, was possibly the first author to advance the idea of extraterrestrials, but this was meant as science fiction.
A new hypothesis (actually quiet old!) arrived on the scene in the 20th Century - panspermia. This literally means that seeds of life exist throughout the universe. It is supposed that the seeds exist mainly in interstellar gas or space - within, and especially outside, our solar system. Life originated because it was seeded on Earth, other planets or moons, and elsewhere in the universe, by comets or meteors in our solar system as well as others in the universe. Just like evolution, the idea of panspermia was first formulated by Greek philosophy, in this case by Anaxagoras in the 5th Century BC. The idea of seed sperma re-occurred in a somewhat different form in Medieval philosophy. Scientists like Hermann von Helmholz in 1878 even suggested a strong programme of panspermia: because he could not prove spontaneous generation, he suggested that life always existed during eternity and not matter. The same view uttered by Russian geochemist V I Vernadskii in the early 20th Century. Later, Svante Arrhenius referred to it again in 1903. Panspermia has gained importance during the past decade, and is supported by such well known and respected scientists, likas SETI League member and astronomer Chandra Wicremasinghe (1939-). With him another famous astronomer, Fred Hoyle (1915-2001) also supported it. My point is that panspermia is no longer merely speculation or fiction. Evidence seems to be growing in favour of this hypothesis. Eventually, panspermia may change in status from a hypothesis to a full-blown theory.
Are evolution and panspermia mutually exclusive? I would like state the following: evolution and panspermia are talking in different voices. They are not the same. The one sees the origin of life in abiogenesis, biology from biochemistry. Panspermia connects Earth with the rest of the universe. Not abiogenesis , but external seeding of life from elsewhere in the universe - even very far from Earth. Would this then make them mutually exclusive, inconsistent with each other? I do not think so. Even were panspermia to attain the status of a theory, I do not see them as necessary conflicting. Both can safely be maintained together. Panspermia does not try to falsify abiogenesis. Bringing building blocks of life from the outside gives a jumpstart to life. It accelerates the process already going on. It acts as a catalyst, but also enriches the life forming processes with new things. On the other hand, there is nothing in Darwinism which excludes the possibility of panspermia. If one should push the ultimate question at its furthest, and ask: where does panspermia's Common Ancestry for life come from? It logically cannot be another common Ancestry. We would then opt for an infinite progression. This far-off, very first life may then have to be explained by evolution - biochemical and biological. Evolution and panspermia tie in to each other. Panspermia does not annihilate evolution; rather, it enlarges it. They are not such very strange bedfellows after all!
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