Can Humans Understand All About Nature?

      

By Nassir H. Sabah

The science produced by humans is necessarily limited by human mental capacity. There is no reason to suppose that this capacity is unlimited, which implies that humans may never understand all about Nature.       There is a general conviction particularly among scientists that science will eventually be able to figure it all out. That might be the case, but on the other hand it might not. It is an open question that cannot be settled with certainty either way, not the least scientifically, until it happens, if ever. To assert that science will be able to explain everything is a comforting thought but is not on solid grounds. After all, the science we know is a product of the human intellect and is therefore constrained by human mental capacities. If these are limited, then any science produced by humans will be limited and will not be able to unravel all of Nature’s mysteries. In talking about science and its future prospects it is usually implicitly assumed that human mental capacities are unlimited. Are they?         Our physical endowments are certainly limited. On the sensory side we are surpassed by many animal species. The sense of smell is much stronger in dogs. Hawks and eagles have superior visual acuity; an eagle can spot a rabbit 3 km away. Birds not only perceive color but, unlike humans, can also perceive ultraviolet light. The eyes of the peacock mantis shrimp have 12 types of photoreceptors, compared to three in human eyes. A rattlesnake can detect temperature changes of 0.003°C or less. Normally, humans can hear sounds in the range 20 Hz to 20,000 Hz. Mice can hear sounds at frequencies as high as 100,000 Hz, and elephants can hear sounds of lower frequencies than humans. The star-nosed mole has six times more sensory touch receptors in its centimeter-wide splayed snout than in the entire human hand.       Some animals have senses that humans don’t have. Sharks and some fish can detect electric fields, and migratory birds can sense magnetic fields. Animals seem to be able to sense earthquakes well before humans. As for physical strength, chimpanzees, whose size is comparable to that of humans, are at least twice as strong on the average.       If our physical endowments are limited, why should our mental capacities be considered unlimited? The basic structure of the human brain is the same as that of the lowest vertebrates. The animal brain evolved primarily as a pattern-recognition device. In searching for food and avoiding predators, animals essentially recognize patterns. Birds recognize edible fruit mainly by its color, shape, and size. A frog dives for cover when perceiving the shape of an approaching bird of prey. The brain mainly grew in size and complexity of interconnections in higher vertebrates and mammals, culminating in the human brain having a cortex of about 16x109 nerve cells, more than that of any other species, and a prominent frontal lobe that is responsible for higher mental functions. Moreover, the cells of the cortex of the human brain are more varied and have more complex interconnections than in any other species. The human brain endowed humans with imagination, abstract thinking, elaborate linguistic skills, exquisite manual dexterity and presumably a higher state of consciousness. But is this enough to enable humans to understand everything about Nature?       If human mental capacities are limited, then any science that humans are capable of producing will necessarily be of limited scope and incapable of unraveling all of Nature’s mysteries. This assertion that science will eventually be able to figure it all out is more a matter of faith, much like religious faith which most scientists reject as being unsubstantiated. Two things can be said about such an assertion.       First, the assertion can be considered an example of counterfactual definiteness, that is, being definitive about something that has not happened for a fact. An everyday example would be to say: “Had I skipped breakfast this morning I would have felt hungry by noon.” This may well be true based on common experience but is not based on fact. The fact is that you had breakfast and did not feel hungry at noon. The turn of events that day could well have been that you skipped breakfast and then accidentally had some misfortune that suppressed your appetite, so you did not feel hungry by noon even though you skipped breakfast. Counterfactual definiteness is inadmissible in the conventional interpretation of quantum theory, and science in general, because, strictly speaking, it is not based on fact.       Second, the assertion that science will be able to explain everything is mainly based on extrapolation of scientific achievement – which has unquestionably been great – into the vast unknown. However, extrapolation outside a common base can be very misleading, as illustrated by the following historical example.       In 1791, Luigi Galvani, an Italian doctor, Professor of Anatomy and researcher, postulated the existence of animal electricity based on his investigation of the contraction of frogs' legs when exposed to a source of electricity. His nephew, Giovanni Aldini, who was also his research assistant, was a bit of a showman. He travelled all over Europe demonstrating to the public how a fresh corpse could be made to jerk an arm or a leg upon application of a sufficiently high voltage – the familiar electric shock that people experience when they accidentally touch a conductor at the mains voltage, for example. Audiences were enthralled by these demonstrations. Here was a dead body moving its arm or leg under the influence of electricity; surely, it was only a matter of time, it was thought, before the dead body would be made to come back to life, that is, humans could be raised from the dead. People were extrapolating from what they could see with their own eyes to what they imagined could happen, but without knowledge of what is really involved in this extrapolation. The jerking of an arm or leg is now well understood to be a local phenomenon according to which the passage of electric current though a muscle in good condition will elicit contraction in the muscle. Bringing back a dead body to life is an entirely different proposition that requires first an understanding of the nature of life, and second, being able to instill life in dead cells. This of course has not yet been realized and is unlikely to be realized in the foreseeable future. All sorts of similar extrapolations are currently being made about new forms of life to be produced in the laboratory, or about bringing back to life dead human bodies that have been kept at extremely low temperatures for this purpose, or about robots having human-like consciousness.       That our mental capacities may not be without limit should not of course stand in the way of our trying to understand everything about the universe. Science is valuable work in progress to be encouraged and supported in every possible way. But to imply with some confidence that humans will be able in the future to understand everything about the universe smacks of a high degree of conceit that is not at all in the spirit of scientific thinking, to say the least.      Nassir Sabah is a neuroscientist/biophysicist and Emeritus Professor of Electrical and Computer Engineering at the American University of Beirut, Lebanon. He has over 100 technical publications, mainly in neurophysiology, biophysics, and biomedical instrumentation and has authored four books on electric circuits, electronics, and neuroscience. This article is adapted from his most recent book Spirituality Rekindled: The Quest for Serenity and Self-Fulfillment (2023). He could be reached at his website  https://nassirsabah.com