The Limitations of Science:
The scientific method is the most fruitful and trusted method of investigation.
It consists of : 1. Making observations. 2. Formulating a hypothesis that can explain what was observed. 3. Testing whether the hypothesis reliably predicts the outcome of further experimentation. 4. Conducting further experiments which will eventually establish the hypothesis as a reliable theory.
The scientific method is entirely dependent on the validity of the initial observations and on the extent to which these can be used to arrive at a reasonable hypothesis. The method cannot be used to address questions that may be at the heart of religious beliefs, which are based on past events, whether imagined or real.
The idea that there is an eternal afterlife in which our souls dwell, once we have departed this life, is a cornerstone of theistic religions such as Christianity and Islam. In these religions it is commonly assumed that animals, other than ourselves, do not possess a soul. The concept of the soul as the essence of humans is, however, ancient. It is found in many religions and, in some of these, indeed extend to animals as well. However, since humans are the product of a long process of evolution, one might well ask at what stage we had acquired a soul and whether our closest primate relatives might not also possess, at least, a late stage in the evolution of the soul.
Enquiries into the existence of human souls and the afterlife have relied on descriptions of Near Death Experiences (NDE’s). These can then be reported in a Journal of Near Death Studies published by the International Association of Near Death Studies.
A substantial study of this nature was undertaken over a period of 13 years in 10 different Dutch hospitals and was reported on December 15, 2001, in a respected international medical journal, The Lancet. All patients had a cardiac arrest, and were clinically dead, with unconsciousness resulting from insufficient blood supply to the brain. In those circumstances, the EEG (a measure of brain electrical activity) becomes flat, and if cardiopulmonary resuscitation (CPR) is not started within 5-10 minutes, irreparable damage is done to the brain and the patient will die.
Of the 344 patients tracked by the Dutch team, 18% had some memory from their period of unconsciousness, and 12% (1 out of every 8) had what the physicians called a "core" or "deep" NDE. The researchers defined that as a memory by the patient from their period of unconsciousness which scored six or more points on a scale published by Dr. Ken Ring in his 1980 study, Life at Death: A Scientific Investigation of the Near-Death Experience. This scale includes, among other things, out-of-body perception, moving through a tunnel, communication with light, blissful feelings, observation of a celestial landscape, meeting with deceased persons, life review, and presence of a border (presumably between life and afterlife).
It is, however, clear that the evidence collected in this manner does not comply with the norms of a scientific investigation, since the evidence collected is anecdotal in nature and could be considered to reflect merely the hallucinations of very sick individuals. Besides it would be very difficult to recruit volunteers to participate in a more scientific study of NDE’s.
There also exists no way in which the scientific method can be applied to test for the presence in humans of a soul which is supposed to enter the afterlife. However, can one reasonably conclude that, because we are not able to apply the scientific method to evaluate the thesis that humans possess a soul, the non-existence of a soul can stand as the truth? The only reasonable conclusion that can be reached is that the possession of a soul or of the eternal afterlife is a matter of a belief, which is fundamental to several religions, but rejected by atheists, who believe, instead, that there is no God, no soul and no afterlife.
In his thought provoking novel, Night train to Lisbon, Paul Mercier raised the interesting question of what one would occupy yourself with in an eternal afterlife, when at first hundreds of years, then thousands, and eventually, millions of years drag by. Having a limited lifespan introduces structure in our lives and, moreover, some gifted individuals leave a legacy in art, music, literature, science and philosophy that can endure for thousands of years. Such prominent persons might not think much about what they could achieve in an afterlife.
Would it be feasible to apply the scientific method to establish how life originated on earth?
In 1862 Louis Pasteur performed a famous experiment to show that microbial life does not appear spontaneously, but always arise from earlier life. This observation became the guiding principal in all subsequent studies in Microbiology and found essential applications in Medicine as well. The demonstration that life can only arise from pre-existing life then lead to the fundamental question as to how the very first life on earth could have originated. The appearance of life out of non-living matter is called abiogenesis and is thought to have resulted in the presence of primordial life forms in stromatolites dating back to 3.5 billion years ago. Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by microbial mats of microorganisms, principally cyanobacteria. The formation of stromatolites has persisted into the present era in several localities such as in Shark Bay, Western Australia. Unfortunately DNA from the ancient forms of life from stromatolite fossils has not survived and the most ancient cyanobacterial DNA as yet is that described by a group of scientists during 2010 in the journal Geobiology. The abstract from their article is given hereunder:
Earth scientists have searched for signs of microscopic life in ancient samples of permafrost, ice, deep-sea sediments, amber, salt and chert. Until now, evidence of cyanobacteria has not been reported in any studies of ancient DNA older than a few thousand years. Here, we investigate morphologically, biochemically and genetically primary evaporites deposited in situ during the late Miocene (Messinian) Salinity Crisis from the north-eastern Apennines of Italy. The evaporites contain fossilized bacterial structures having identical morphological forms as modern microbes. We successfully extracted and amplified genetic material belonging to ancient cyanobacteria from gypsum crystals dating back to 5.910–5.816 Ma, when the Mediterranean became a giant hypersaline brine pool. This finding represents the oldest ancient cyanobacterial DNA to date. Our clone library and its phylogenetic comparison with present cyanobacterial populations point to a marine origin for the depositional basin. This investigation opens the possibility of including fossil cyanobacterial DNA into the palaeo-reconstruction of various environments and could also be used to quantify the ecological importance of cyanobacteria through geological time. These genetic markers serve as biosignatures providing important clues about ancient life and begin a new discussion concerning the debate on the origin of late Miocene evaporites in the Mediterranean.
The ancient DNA that these workers managed to amplify by means of the polymerase chain reaction were fragments of bacterial 16S ribosomal RNA, which is widely used in the classification of bacteria.
The Messinian Salinity Crisis occurred as a result of a closure of the Strait of Gibraltar, that lasted from 5.96Ma to 5.33Ma. During this period dry climatic conditions caused the Mediterranean to dry out and shrink in size, at times and in some places forming a dry basin 3 to 5 km below the level of the World’s oceans. Whatever water flowed into this basin came from rivers during less dry periods. Plantlife and also microorganisms became encased in sediments. If indeed DNA samples extracted from gypsum crystals, that were formed during this period, represent the most ancient record of cyanobacteria ever found we fall far short of having a DNA record of cyanobacteria as being amongst the earliest microbes that are thought to have appeared about 3.5 billion years ago.
The formation of stromatolites is, however, an ongoing process in various places on the planet and so we can also investigate DNA samples obtained from extant cyanobacteria, to be found in stromatolites formed during the present era. Cyanobacteria carry on photosynthesis, thus releasing oxygen and are thought to have played an important role in converting the early reducing atmosphere of the earth into an oxidizing one. They also play an important role in converting nitrogen gas into bioavailable forms such as ammonia, nitrate and nitrite, that can be utilized by plants. Japanese workers have compiled a database of the Cyanobacteria that they called Cyanobase. Cyanobase has 39 entries for various species and subspecies of cyanobacteria. The number of genes identified in these 39 organisms vary between 1757 genes for the smallest genome to 6676 genes for the largest. By comparison the smallest genome of any free living organism is that of Pelagibacter ubique that encodes 1389 genes. There is at present no record of much simpler, free living organisms that could get by with far fewer genes. This must have been the case if indeed abiogenesis were to have taken place billions of years ago, but this thesis lacks confirmation by the scientific method.
To date it, therefore, seems that Louis Pasteur could have been right: Life can only come from prior life, an observation supported by work in numerous laboratories for more than a century. And this leaves science groping for answers: How did the first life originate? Several teams of scientists are actively working on abiogenesis, the emergence of life from non-living material. The intractability of this area was, however, perhaps best summarized by Lilley and Sutherland: “We are not experts on the origins of life. But who is? There is no record left from that time, no fossils”.
One can only wonder; could life perhaps have started with a Bang like our Universe?
Lancet (2001) 358, 2039 -45.