Posts Tagged ‘life’

What Can We Truly Know? A Practical Guide to Truth for Finite Minds

June 1, 2025

Truth feels like it should be simple: something is true if it matches reality.

But as soon as we ask how we know something is true – or whether we can know – we realize the ground shifts under our feet. We have finite minds, limited senses, and we’re trying to understand an endless universe from the inside. We do not know what senses we do not have. The only thing we can be certain of is that whatever we observe of the surrounding universe is partial and incomplete. And we do not know what we cannot know. How do we define truth from such a small vantage point?

This is an attempt to build a definition of truth that respects those limits while still giving us something reliable to live by.


Our senses have evolved on earth to detect conditions on earth and so help our journey of survival and reproduction. Our minds evolved to help us survive, not to decode the cosmos. We’re built to spot patterns, avoid danger, find food, and navigate social groups – not to unravel quantum mechanics or grasp the shape of space-time. Yet we have been so successful at survival that we have had time to consider other things than survival.  We have evolved language and thinking and have earned the freedom to demonstrate our creativity. We have built tools, systems, and cities and vehicles. We have developed the sciences and philosophy and the arts such that we are by far the most successful species on the planet.  Human cognition too has grown and far beyond our original limits. But even with all that, our understanding is still partial, still incomplete. Always will be. Our cognitive limits are ever-present. For example, we still cannot comprehend why gravity must be or why existence is or time flows or life and consciousness arise. There are things – perhaps – that we cannot know.

That means truth, for us, has to be redefined. Not as an unreachable absolute, but as something we can approach and refine, even if we never fully arrive. Consider all truth in the universe to be a giant landscape. We only see a tiny part of that. From that which we can see our truths are what we call knowledge.  That which is knowledge for us is always true (provisionally). A lie is disqualified from being knowledge. We perceive knowledge to come in three forms:

1. What We Know

These are the things we’ve tested, confirmed, and rely on – like gravity pulling objects down or the fact that ice melts above 0°C. These are our working truths. They could be revised, but they serve us well for now.

2. What We Could Know

These are truths we haven’t reached yet, but potentially could. Maybe we need better tools or smarter questions. The cure for a disease. The cause of consciousness. A deeper law of physics. These are knowable truths – just not yet known.

3. What We Can Never Know

Some truths lie forever beyond human perception or understanding. Perhaps they’re hidden by our cognitive limitations or the boundlessness of space and time. Or maybe our brains are simply incapable of grasping them – like trying to teach calculus to a dog. These are the unknowable truths – still real, just what we cannot know.

If that’s our playing field, then a more grounded way to define truth is:

Truth is what fits with what we know so far, helps us predict what happens next, and holds up when tested.

This isn’t some eternal, absolute cosmic Truth-with-a-capital-T. It’s the kind of truth we can use, refine, and build on. It works in science. It works in everyday life. And it keeps us honest. We are truth-seekers, not truth-holders. No matter how clever we get, we’ll never know everything. That’s not failure – that’s the condition of being human with a finite brain and limited senses. But we can keep trying and keep improving our aim. We can ask better questions, challenge assumptions, discard broken ideas, and refine our hypotheses and our theories. The scientific method does exactly this. So does philosophy. So do our creative arts though truths are very strictly subjective. So does any kind of honest thinking. Not to own the truth, but to move closer to it.

Truth Is a direction, not a destination. It is the seeking for the truth that matters especially since any absolute truth is beyond out cognition. We can move toward it, sometimes fast, sometimes slow, but we never quite arrive. And that’s okay. What matters isn’t reaching a final answer. What matters is that we seek.

We live in a universe full of mystery. The best we can do is stay curious, stay humble, and keep searching.

We are seekers after truth not its owners.


Philosophy has never – ever – answered any question

September 27, 2024

The usual definitions of philosophy are along the lines of (Oxford Languages):

  1. the study of the fundamental nature of knowledge, reality, and existence, especially when considered as an academic discipline.
  2. a theory or attitude that acts as a guiding principle for behaviour. 

But this leaves me very dissatisfied. I am especially irritated by the reference to an academic discipline. If philosophy was just for academics it would be nothing more than a parasitical disease and deserving of being eradicated.

I observe the following:

  1. Philosophy only deals with unanswerable questions. The study of philosophy “increases understanding” but has never, ever, conclusively or finally, answered a question.
  2. For the decidedly finite human mind (brain + senses), there are many things which cannot be known.
  3. What cannot be known is a function of the mind (senses + brain = species) in question.
  4. What a dog cannot know is different to what a chimp cannot know. What homo sapiens cannot know today is different to what homo superior will not be able to know sometime in the future.
  5. As species evolve the unanswerable questions change.
  6. Where a question has an answer, it is not philosophy.
  7. Philosophy is about first posing questions that cannot be answered. Then it is about seeking answers and the methods of seeking answers.
  8. Philosophy may increase understanding of the difficulties of finding answers to particular questions and help to set limits around the questions, but never has (and never will) definitively answer such fundamental questions
  9. We are no closer to knowing the nature of reality, truth, existence, consciousness, causality, time or knowledge now than we were 10,000 years ago.

It seems to me that we have to start with the fact that human cognition is limited. Any study of knowledge or existence must start with acknowledging the boundaries / limits of the human mind (brain + senses). Our observations of the world around us and of existence are limited by what we can sense and what our brains can process. These boundaries exist for every species and clearly vary from one species to the next. Evolution, not thought, can change these boundaries. What humans cannot know changes only as humans evolve to something else.

Philosophy is about knowledge and its limits.

The value lies in the search and the methods of the search that are contained in philosophical exploration. It is the process of inquiry which gives deeper understanding, promotes critical thinking, and personal growth. Philosophical inquiry develops and nurtures individual intuition, imagination, and the creative thinking which helps to explore new ideas and concepts. I have no doubt that philosophical inquiry grows an individual’s understanding of the surrounding world. Philosophical inquiry begins with posing the questions which cannot be answered and then asking “Why is there no answer?”

But what cannot be known by humans remains what cannot be known. Philosophy answers no questions (never has, and never will). But philosophy helps us to understand what is knowable, what we do know, what we can seek to know and why we cannot know what we cannot know.

So I would redefine philosophy as being

“the search for the boundaries of knowledge and of thinking which limit the understandings of the human mind”.


Home truths 1: Science & Philosophy

July 26, 2024

I find it ridiculous that the general assumption is that we know all about gravity. The reality is that we have no idea about why it exists or how the force of gravitation works. We can calculate the effects of gravity essentially still using Newton’s laws together with Einstein’s tweaks. But we have not the faintest idea about how one mass attracts another or why it should. How does the sun communicate with the planets and tell them what force applies  – if it does. A fundamental particle called the graviton is the proposed solution but we have never found one and it lives in the land of the Jumblies. We do not even have any idea what mass is. Physics even has massless particles (the gluon, the photon and the imaginary graviton) but only the God of Physics knows what massless, matter-less stuff such particles may contain. The reality is that science is strictly limited. It is limited by its fundamental assumptions and its boundary conditions. It cannot address matters outside of these conditions.

We put down motion at a distance to forces such as gravitational or electromagnetic. But we really have no idea how these forces are mediated. Probably by Mysterious Quantum Wave Functions which collapse conveniently when needed. But who knows why they exist? And let us be clear. Particles do not exist in two places at the same time. Never. And any physics which says so lives in the land of the Jumblies.

I am just trying to clear my mind by writing down my (current) home truths. I have chosen to arrange my “core beliefs” in three categories as 3 separate posts.

  1. Science & Philosophy
  2. Behaviour
  3. Society & Politics

I start with Science and Philosophy. The list below could have been much longer but I stopped when I started getting bored.


Home truths 1: Science & Philosophy

  1. We have no clue as to the question which existence is the answer to.
  2. We only have circular definitions for truth but what does exist (we assume) is true.
  3. The human mind is finite. There are things that are known, things that are knowable but unknown and there are things that cannot be known (the unknowable).
  4. Infinity, by definition, is a label – in language – for that which cannot be comprehended.
  5. Boundless, endless, timeless and infinite, just like before the beginning and after the end, are labels for the incomprehensible, no matter what the pretense.
  6. The human capability for language is genetic and unmatched by any other species on earth.
  7. The capability for language is discovered but all languages are invented.
  8. Once the concept of oneness – identity / one(1) – is defined, all other numbers of every kind are fixed. Once one (1) exists every other number of every kind automatically follows. Note that zero comes after 1 and derives from 1 – 1.
  9. One and all the numbers derived therefrom are concepts and do not exist explicitly in nature.
  10. All numbers are unreal and abstract.
  11. The process of counting and all of what is now called number theory are also derived from, and fixed by, the concept of one.
  12. Mathematics describes abstract relationships and abstract patterns connecting abstract concepts and does this using a number of invented languages. It is not a science.
  13. The practice of mathematics is art rather than science.
  14. Language is what gives humans the ability to describe the unreal, the past, the future and to lie.
  15. All languages are silent about the truth value of what is being described by language.
  16. Nonsense language is the perfectly correct use of language but where the content is nonsense.
  17. To create nonsense language or nonsense mathematics (in the manner of Edward Lear or Srinivasa Ramanujam) needs very great skill and great proficiency in the language.
  18. Mathematical equations are just propositions, as any sentence in any language, and are silent about the truth value of the content.
  19. Writing a mathematical equation provides no proof of that equation.
  20. Time is unidirectional and a brute fact of our universe. Negative time is not possible in our universe.
  21. The flow of time and existence emerge together.
  22. Mathematical equations for theories having negative time are merely nonsense mathematics (correct by the rules of mathematics but having nonsense as content).
  23. Physics and other scientific theories which do not explicitly exclude the possibility of negative time are incomplete or false.
  24. Scientific theories which are silent or are unable to exclude the possibility of negative time do not imply any support for the possibility of negative time.
  25. No logic system (or science) can ever prove the fundamental assumptions it is itself based upon.
  26. Science assumes that existence, the flow of time, causality, life and consciousness are all self-evident. Therefore science cannot address, let alone explain, any of them.
  27. Anything truly random (without cause) is inexplicable. Random is part of what we cannot know (or else it is Divine).
  28. Every scientific discipline assumes that cause precedes effect but ignores the unavoidable first cause problem.
  29. The Cosmic Big Bang theory cannot explain why there had to be a Big Bang.
  30. Matter forever or matter from nothing are equally inexplicable and unsatisfactory.
  31. Mass “is the amount of matter in matter” which means we have no clue as to what mass is.
  32. We do not know why there are as many “fundamental” particles as there are (or seem to be).
  33. We do not know why the fine structure constant is exactly the number that it is (or why the speed of light is what it is).
  34. Something from nothing cannot be explained by any Science nor by any theology or belief in a God.
  35. Time without beginning cannot be explained by any Science nor by any theology or belief in a God.
  36. A global zero made up of an arbitrary  local “+ dark energy” and balanced by a local “- gravitation energy” proves nothing.
  37. The concept of nothingness is beyond the finite human mind. (Zero derives from 1 and is not a description of nothingness).
  38. Why the universe (including its dimensions, matter, energy and all other properties) is compelled to exist is unknown. (This is an alternative formulation of home truth 1.1)
  39. There is no known explanation for the spark of life.
  40. Consciousness is a mystery without explanation.
  41. Though we can calculate its effects, nobody has the faintest inkling of how gravity is mediated or how it works.
  42. Nobody has a clue as to how large the universe (and not just the observable universe) is (or how big the Big Bang was).

God or no-God? That is the wrong question

August 24, 2021

I find debates where one unprovable belief battles against other unprovable beliefs to be tiresome. Human cognition does not allow an absence of belief. A claimed non-belief is, of course, just another belief. I find statements of the kind “I do not know, but I know it isn’t that” to be self-contradictory and shallow. I find invocation of the scientific method, or of Divine Beings, without reference to boundary conditions and the limits of knowability, to be incomplete and invalid as arguments. This essay is just my attempt to marshal my own thoughts as to why I find it so.

(revised 26th August 2021)

The primal need to know

Human cognition demands that the world around us is ordered and rational and that it is capable of being understood. This is the fundamental and overriding assumption that pervades all thought and human endeavour. Science begins with this assumption of order in all parts of the universe and throughout all time. In addition, science assumes that causality, and the arrow of time, apply. The human brain is finite, and its attendant senses are limited. We do extend our sensory range with instruments but even these must convert their detected signals to be what humans can perceive directly by their senses and interpret with their brains. Even when looking at the same thing, what the eyes of a dog see as interpreted by a canine brain, is different to what a human eye sees as interpreted by a human brain. Whatever, and all, that humans observe are just their perceptions and are always subjective.

Human comprehension is “cabined, cribbed, confined, bound in” by the capabilities of the brain/sense combination. That some things are unknowable to the finite human mind is inevitable. Reason tells us that knowledge is whatever a brain can comprehend to be knowledge. Epistemology is a whole branch of philosophy dedicated to understanding the nature of knowledge. And yet we can do little better than concluding from all our analyses that knowledge is what knowledge is. Whatever lies beyond human comprehension is the realm of the unknowable. Observation is limited to what exists and is observable by the human brain/sense combination. Human reason and comprehension, though finite, can contemplate the unknowable, but without any hope of comprehension. Human language (including mathematics) can encompass both the real and the unreal. Language can describe things that do not exist. But when language addresses the unknowable it only deals in labels. The brain using that language cannot wrap itself around the unknowable which it labels. What we do not know, we seek and sometimes find. What we cannot know we can never find, and yet we seek. I cannot help but conclude that it is the seeking, not the acquisition, of knowledge, which is a primal characteristic (perhaps a purpose) of the human species.

But the ego of human cognition is such that it does not allow the inexplicable to remain dangling and unaddressed. That all mysteries must have, and require, explanation is a distinguishing characteristic of the human species. Human cognition abhors a mystery without an explanation. Anything mysterious or incomprehensible is always, eventually, explained away by an appropriate invocation of unknown, unknowable, imagined states or powers. It applies as much to science (metaphysics) as to philosophy or to theology. The explanations are often just labels for speculations which harness the unknown and the supernatural. Reason tells us that everything has a cause, but the First Cause problem defeats us. Our language allows us to formulate self-contradictory impossibilities. Before the beginning, we say and after the end. When our reason and our logic make recourse to infinite regress, it is often dismissed because it is incomprehensible. When we reach the unknowable, we invent new labels for abstract concepts such as divine or supernatural or infinity or forever. Never mind that they are unknowable. An infinite space or a forever existence are inherently incomprehensible and magical. We pretend that inventing a label brings us closer to understanding.

God Theories and the invention of Gods

In human discourse, the invention of God Theories and of Gods came about as we sought answers and explanations for inexplicable relationships observed in the surrounding physical world. The invocation of Sun-gods and wind-gods and weather-gods seems both obvious and inevitable in the early history of man. The invented explanations – again inevitably – required the existence of supernatural states and the exercise of powers beyond human capability. It was entirely logical and reasonable, then, that postulating the existence of supernatural or superhuman powers or states was entirely justified by the greater need to bring a perceived order to the observed world. To have a perceived order in the physical world was primal. The emotional human need for spirituality was also partly satisfied by the inclusion of the supernatural. With this world view, which allowed incomprehensible states and supernatural powers, these Great Explanations invoking the unknowable were quite reasonable, even if they were all merely labels for what could not be comprehended. Mysteries were replaced by labels which implied, but never actually bestowed, understanding. As human knowledge and sophistication increased, the need for the supernatural also adjusted to the new mysteries uncovered. It was not necessary for these supernatural states or powers to be invested in imaginary Beings, but some mediator was necessary for the exercise of supernatural powers. What the human mind considers reasonable is dynamic and shifts as learning occurs and knowledge increases. Given the existence of unknown, extra-natural forces, it was entirely reasonable, then, to imagine a living entity, a Being, as the mediator. Doing so certainly did improve the narrative. The first Sun God had the power to make the Sun rise every day. This explanation did not necessarily have to be invested in a Being, but it was convenient. It was merely for the ease of the narrative that these Beings took on forms and shapes and behaviours that were close enough to human forms and behaviours to be recognised and identified with. And so were born the Theories of Gods, the Gods, and the various pantheons of gods.

It is my contention that

  1. Human comprehension is finite and limited, and
  2. demands that order be perceived in the world.
  3. Incomprehensibilities and mysteries need to be explained to maintain the perceived order of the world, and
  4. invoking supernatural states and powers allows unanswerable questions and infinite regressions to be closed.
  5. Supernatural states and powers need a mediator, and therefore
  6. Beings invested with such states and powers have been invented as the mediators.

Inexplicabilities and mysterious events were most conveniently explained as the work of unknowable, supernatural or superhuman things. That these imagined things, labelled gods, were then imbued with the quality of being and of having forms and shapes and behaviour and families was, and is, mere embellishment. The fundamental reason for inventing any god was to be able to answer or explain the inexplicable. Every God ever invented was, at its core, a Theory of Explanation.

Religion, of course, is something else (see Notes).

The Great Mysteries

Where once we resorted to supernatural Beings, cosmology and metaphysics now resort to equally fanciful Theories. We have not had a new God invented for over a thousand years. We have had many Theories propounded though. The theories of today are consistent with the knowledge of today. They are as astute (or as ridiculous) as the God Theories of old.  The number of theories in cosmology about the origins of the universe are as numerous today as the multitude of ancient creator gods. The common feature is that these Theories, then as now, speculate about the incomprehensible and the unknowable. I observe that atheism today is very often all about debunking these God Beings, these deities in the image of man. They often focus on the attributes of the invented Beings. But this is superficial, and atheism rarely addresses the great mysteries which led to the invention of the God Theories in the first place.

What is considered inexplicable has changed over the years though many of the inexplicabilities have only changed cosmetically and in formulation. None of the great, deep mysteries about life the universe and everything have changed much or been resolved. The ultimate questions about the physical world regarding matter and energy and motion have not vanished either; they have just become much more sophisticated. We now say we know why the earth rotates around the Sun though we still have no clue as to how gravity is mediated. We know exactly how the effects of gravity can be calculated and we can traverse the distant reaches of space. But we have no clue as to why the perceived force follows an inverse square law and not the inverse cube law or something else. We can calculate the effect of electro-magnetic fields and can generate light and electricity and heat and motion almost at will. But we still have no clue as to how the earth communicates to a raindrop that it must move towards the surface of the earth. When we throw a ball in the air, we still have no idea of how the earth tells the ball it is time to change direction and fall. Einstein’s spacetime would say that the earth’s gravity distorts the fabric of the spacetime in which the ball exists such that it has no choice but to move down the spacetime slope towards the earth. But “down” is defined by gravity. To “move down” merely invokes another form of some kind of super-gravity, for there is no reason for any motion up or down a slope unless there is an overriding force. (When in doubt we can always just invent a new fundamental particle imbued with supernatural powers as the mediator. Let us call it a graviton). Nevertheless, we believe we now know why the earth orbits the Sun and have consigned the Sun-gods to the realm of the redundant. But the stark reality is that we still do not know how gravity is mediated.  It is noteworthy that the word gravitation could be replaced by the words magical attraction in any scientific text without any loss of meaning. (See notes). Admitting to magic, however, is not politically correct or acceptable. Instead, we now invoke the Theories of Relativity and Quantum Mechanics with spooky actions shrouded in mystery, except that we no longer label these metaphysical Theories as Gods.

Quantum mechanics dreams of a single all-encompassing quantum wave function, as just one particular instance of an incomprehensible infinity of possible wave functions. This Ultimate Wave Function which happens, by chance, to collapse to give all the other wave functions which in turn give us and the universe which we inhabit. One Ultimate Wave Function to rule them all. The quantum vacuum is not quite completely empty since it has the laws of quantum mechanics embedded within it. It is another Theory of Explanation which might as well be called the God of Quantum Mechanics. Though I am not clear if the God of Random Interaction is the Son or the Father. With the God of Gravity they make up a Trinity.

All the Great Mysteries – Existence, Causality, Time, the arrow of time, Life, Identity, Consciousness, Spirituality, Ethics, and Morality – have been great mysteries for at least 10,000 years and are still great mysteries. I do not include Mathematics in my list of Great Mysteries. I take the view that Mathematics is an invented language describing relationships in our observed world. Like all languages, it can also describe things that do not exist or are ridiculous. The beauty of relationships observed in the real world are not due to Mathematics, but due to the mystery of Existence and as described by Mathematics. Beauty lies in the thing not in the language describing the thing.

Mathematics started in prehistory with counting and the study of shapes

The metaphysics of existence remain mystical and mysterious and beyond human cognition, as much today as in prehistoric times. Nevertheless, it is the cognitive capability of having the concept of a unique identity which enables the concept of one……. Numbers are not physically observable. The concept of one does not, by itself, lead automatically to a number system. That needs in addition a logic system and invention (a creation of something new which presupposes a certain cognitive capacity). It is by definition, and not by logic or reason or inevitability, that two is defined as one more than the identity represented by one, and three is defined as one more than two, and so on. Note that without the concept of identity and the uniqueness of things setting a constraint, a three does not have to be separated from a two by the same separation as from two to one. The inherent logic is not itself invented but emerges from the concept of identity and uniqueness. That 1 + 1 = 2 is a definition not a discovery. It assumes that addition is possible. It is also significant that nothingness is a much wider (and more mysterious and mystical) concept than the number zero. Zero derives, not from nothingness, but from the assumption of subtraction and then of being defined as one less than one. That in turn generalises to zero being any thing less than itself. Negative numbers emerge by extending that definition. The properties of zero are conferred by convention and by definition. Numbers and number systems are thus a matter of “invention by definition”, but constrained by the inherent logic which emerges from the concept of identity.

We have discovered and can enumerate more Laws of Nature now than we ever could. But why these particular laws exist and none other, remains a Great Mystery. The existence of the natural laws, of matter, of energy and even of space itself remain as answers to unknown questions. We do not know what compels them to be what they are. The spark of life remains elusive. If nothing else the apparent purpose of all living things to survive, grow and replicate has appeared from Chance knows where. A purposeful chance is to delve into the unknowable. 

They all boil down, in my view, to two fundamental Great Mysteries. I find that they can be grouped either under Existence or under Life. Causality, Time, and Identity all emerge from the Great Mystery of Existence. It seems logical to me that Consciousness, Spirituality, Ethics, and Morality are mysteries which follow from the Great Mystery of Life. I used to subordinate the Life Mystery to the Mystery of Existence, but I think the injection of an apparent purpose elevates Life to be as great a mystery as Existence.

The fundamental questions

What leads to life the universe and everything?

God or no-God? is, in my view, a rather shallow question. There is no great mystery in the invention of gods. Every God ever invented was, at its core, a Theory of Explanation. And even if we get to find the God of the Theory of Everything, we would still have to reach for the unknowable to comprehend Existence and make sense of Life.

The fundamental Great Mysteries have always been, and still are:

  1. Why existence? and
  2. Why life?

Note 1.

Gods need to be distinguished from religions.

My take on religions is that they came later, after beliefs in gods had caught the human fancy. They came together with, or because of, an increasing need for human societies to organise themselves. They provided a way for the exercising of political power by utilising the human need for spirituality and exploiting the established beliefs in gods. All organised religions, whether they admit to it or not, are attempts to influence the behaviour of others and are all, unavoidably, cases of exploiting belief for the exercise of political power. I find the lip-service paid to the separation of state and religion rather meaningless since all organised religions – as all states and political parties – are involved in the business of influencing the behaviour of others.

Note 2.

Take, for example, this text from the Wikipedia article on Gravity where I have replaced the words “gravity” and “gravitation” with “magical attraction”.

Gravitation Magical Attraction, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light —are attracted to (or gravitate toward) one another. On Earth, gravity magical attraction gives weight to physical objects, and the Moon’s gravity magical attraction causes the tides of the oceans. The gravitational magical attraction of the original gaseous matter present in the Universe caused it to begin coalescing and forming stars and caused the stars to group together into galaxies, so gravity magical attraction is responsible for many of the large-scale structures in the Universe. Gravity Magical Attraction has an infinite range, although its effects become weaker as objects get further away.

Gravity Magical Attraction is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915), which describes Gravity Magical Attraction not as a force, but as a consequence of masses moving along geodesic lines in a curved spacetime caused by the uneven distribution of mass. The most extreme example of this curvature of spacetime is a black hole, from which nothing—not even light—can escape once past the black hole’s event horizon. However, for most applications, Gravity Magical Attraction is well approximated by Newton’s law of universal gravitation Magical Attraction, which describes Gravity Magical Attraction as a force causing any two bodies to be attracted toward each other, with magnitude proportional to the product of their masses and inversely proportional to the square of the distance between them


If a virus is not alive, how does it die?

March 24, 2020

You can’t strictly kill a virus since it is not alive.

Outside living cells, some viruses remain potentially active for thousands of years. A virus recovered from permafrost was able to infect an amoeba. Influenza and corona viruses are thought to stay active for a few hours or days. But the smallpox virus can remain active for years

These days there are many reports about how long the coronavirus remains “alive” or “viable” or “active” on surfaces.  For example this is an abstract of a new paper (yet to be published):

Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1

Abstract
HCoV-19 (SARS-2) has caused >88,000 reported illnesses with a current case-fatality ratio of ~2%. Here, we investigate the stability of viable HCoV-19 on surfaces and in aerosols in comparison with SARS35 CoV-1. Overall, stability is very similar between HCoV-19 and SARS-CoV-1. We found that viable virus could be detected in aerosols up to 3 hours post aerosolization, up to 4 hours on copper, up to 24 hours on cardboard and up to 2-3 days on plastic and stainless steel. HCoV-19 and SARS-CoV-1 exhibited similar half-lives in aerosols, with median estimates around 2.7 hours. Both viruses show relatively long viability on stainless steel and polypropylene compared to copper or cardboard: the median half-life estimate for HCoV-19 is around 13 hours on steel and around 16 hours on polypropylene. Our results indicate that aerosol and fomite transmission of HCoV-19 is plausible, as the virus can remain viable in aerosols for multiple hours and on surfaces up to days.

But then I also read that viruses are not “alive”. They are just a bunch of chemicals, non-bacterial pathogens,  which, by unknown mechanisms, just happen to have

  1. long molecules of DNA or RNA that encode the structure of the proteins by which the virus acts;
  2. a protein coat, the capsid, which surrounds and protects the genetic material; and
  3. in some cases an outside envelope of lipids

Scientific American:

For about 100 years, the scientific community has repeatedly changed its collective mind over what viruses are. First seen as poisons, then as life-forms, then biological chemicals, viruses today are thought of as being in a gray area between living and nonliving: they cannot replicate on their own but can do so in truly living cells and can also affect the behavior of their hosts profoundly. The categorization of viruses as nonliving during much of the modern era of biological science has had an unintended consequence: it has led most researchers to ignore viruses in the study of evolution. Finally, however, scientists are beginning to appreciate viruses as fundamental players in the history of life. …..

What exactly defines “life?” A precise scientific definition of life is an elusive thing, but most observers would agree that life includes certain qualities in addition to an ability to replicate. For example, a living entity is in a state bounded by birth and death. Living organisms also are thought to require a degree of biochemical autonomy, carrying on the metabolic activities that produce the molecules and energy needed to sustain the organism. This level of autonomy is essential to most definitions.

Viruses, however, parasitize essentially all biomolecular aspects of life. That is, they depend on the host cell for the raw materials and energy necessary for nucleic acid synthesis, protein synthesis, processing and transport, and all other biochemical activities that allow the virus to multiply and spread. One might then conclude that even though these processes come under viral direction, viruses are simply nonliving parasites of living metabolic systems. But a spectrum may exist between what is certainly alive and what is not.

A rock is not alive. A metabolically active sack, devoid of genetic material and the potential for propagation, is also not alive. A bacterium, though, is alive. Although it is a single cell, it can generate energy and the molecules needed to sustain itself, and it can reproduce. But what about a seed? A seed might not be considered alive. Yet it has a potential for life, and it may be destroyed. In this regard, viruses resemble seeds more than they do live cells. They have a certain potential, which can be snuffed out, but they do not attain the more autonomous state of life. Another way to think about life is as an emergent property of a collection of certain nonliving things. Both life and consciousness are examples of emergent complex systems. They each require a critical level of complexity or interaction to achieve their respective states. A neuron by itself, or even in a network of nerves, is not conscious—whole brain complexity is needed. Yet even an intact human brain can be biologically alive but incapable of consciousness, or “brain-dead.” Similarly, neither cellular nor viral individual genes or proteins are by themselves alive. The enucleated cell is akin to the state of being braindead, in that it lacks a full critical complexity. A virus, too, fails to reach a critical complexity. So life itself is an emergent, complex state, but it is made from the same fundamental, physical building blocks that constitute a virus. Approached from this perspective, viruses, though not fully alive, may be thought of as being more than inert matter: they verge on life.

But how then do they die? Clearly there has to be a chemical change. Is it just a case of going from active to inactive as chemistry changes?

And that begs the question as to what that chemical change might be.


 

Life exists as a succession of identities

November 18, 2017

Life is an abstract concept manifested as living things. The thread of life has no discernible beginning.

Life – to be life – must be manifested in an entity capable of reproduction. The elements displaying life either continue or come to an end. The thread is carried as a possibility by every sperm and every egg but the sperm and egg cannot themselves reproduce. Most of these possibilities come to an end before the two combine. If – and only if – a sperm and egg do combine, then life continues as, and within, a unique identity created by that combination. It is the creation of the identity – at conception – which continues life. About one in 300 billion sperm survives to combine with about one in 200 eggs to create an identity. It is a unique genetic identity. That identity, first as a fetus may end before birth. Or it may continue after birth as a child. It may grow to be an adult human and give rise to further sperm or eggs before itself coming to an end. When that identity qualifies to be considered a human entity and protected by society is a choice for the societies and the individuals concerned. Most societies start assigning the identity some rights and protections before birth but only after about 20 weeks of life as a fetus.

There is little doubt, however, that a unique genetic identity is created at conception, whether in a test tube or in a womb. At what stage of development that identity achieves consciousness and then self-awareness is not certain but almost certainly only after a rudimentary brain has formed. That would be some weeks after conception but probably some little time before birth. At what point that identity is to be afforded legal “rights” is then a matter for the surrounding society to determine.

Until the identity reaches birth – whether by natural or by artificial means – it has no options and no choices to exercise. Whether self-aware or not, its existence is in the gift and the power of others. It starts acquiring choices and freedoms of action only after birth, as allowed or constrained by its own development and the rules of the society it finds itself in.

Life then only exists as a succession of identities.

To trace the beginning of life would require going back from identity to identity to the specific cells some 3.7 billion years ago. A collection of sperm and eggs may contain the elements for life to continue but do not in themselves constitute life. The beginning of an identity is not the beginning of life. But the act of conception brings a unique identity into being and it is surely the beginning of a specific new life.

Life may be continuous as a concept but can only be realised and manifested as a succession of unique, discrete identities.


 

When is a strawberry dead?

June 25, 2013

An interesting discussion yesterday on BBC Radio

What Is Death?

Series 8 Episode 1 of 6 Monday 24 June 2013

“What Is Death?”

In the first of a new series of the award winning science/comedy series, Brian Cox and Robin Ince are joined on stage by comedian Katy Brand, biochemist Nick Lane and forensic anthropologist Sue Black to discuss why death is such an inevitable feature of a living planet. As well as revisiting such weighty scientific issues, such as when can a strawberry, be truly declared to be dead, they’ll also explore the scientific process of death, its evolutionary purpose and whether it is scientifically possibly to avoid it all together.

The death of a strawberry had apparently been discussed on an earlier program last year:

Brian Cox Strawberry

A fascinating discussion regarding when a cell can be truly considered “dead” though I couldn’t quite agree that death was necessary to evolution. Only birth is of course. It would be pretty crowded without death but life – or death – after procreation no longer has any part to play in the passing on of genes to the next generation or on evolution. With immortality there would, of course, be no need for procreation or for any future generations. But if immortal beings did beget other immortal beings then an Infinite Universe would come in very handy. However, the fertility rate needed for replenishment of the mortal members of a species is unconnected to the longevity of the individuals and I cannot see that death, per se, has any impact on evolution.

As far as the life and death of a strawberry are concerned it seemed to me that the question was essentially meaningless. You could as well ask if your finger could be alive when it no longer was connected to your body. A finger -like a strawberry is never truly alive unless connected to the body that it is a part of and the question of life or death when it is separated from its host body is moot.

Self-replicating fingers – or strawberries – would make John Wyndham’s Triffids seem benign.