If you think definitions are a great way of getting rid of confusions, if you think definitions can help you get crystal clear understanding of the way things are, well, read on.
Ask young kids the difference between animals and birds, and the general response will be
birds fly, animals cannot
As we age, we learn that, “all birds are animals, except that birds are animals that can fly”. Then we learn about birds that cannot fly, like Kiwi, Ostrich, Penguin etc. Then we also learn about what we thought earlier to be birds, are actually not birds, like bats. We learn that bats are mammals (animals) that can fly.
But who decided all this? That bats cannot be birds? And if birds are creatures that fly, then Kiwi is still a bird, but the one which cannot fly?
We then realize that it is all in the definition. Like, animals are defined as multicellular, eukaryotic organisms. Which means all multi-cellular beings are animals. But what about plants? Common sense tells us that they definitely aren’t animals. But going by this definition, they are!! Except that, plants produce their own food via photosynthesis, while animals do not or rather cannot.
But wait, there are plants that are not photosynthetic as well! And historically, in ancient times, plants and animals were two different classes of living beings! And back then, algae and fungi were plants as well. But today, by definition, plants are animals as well, while algae and fungi are neither plants nor animals! And, additionally today we have prokaryotes and viruses as well!
So it is not just in the definition. But in the time period of definitions. If we go back in time, definitions were different. Take the case of Pluto. A couple of years ago, Pluto was a planet and there were nine planets. Today, Pluto is not a planet anymore, and there are only 8 planets! Pluto was demoted due to a change in the definition of what a planet is.
But again, even after this change of definition, there are people who do not approve of Pluto not being a planet. And it is not just some ordinary folks. NASA Administrator Jim Bridenstine doesn’t agree with Pluto not being a planet. There is a whole movement out there that wants to restore the status of Pluto as a Planet.
So now, it is not just about changing definitions over time. It is about, which definition you agree with. Those who think Pluto is a planet have a different definition for planets when compared to those who do not think it is a planet.
So what are students supposed to do in exams? Well, go by the text book definition of things. If their text book says it is a planet, then it is, otherwise it is not! That way, leave aside the confusion to the experts, and focus on what amounts to be the right answer in the exam.
What then really is Pluto? A planet, or not? Ask Pluto, and well, it doesn’t care. Whether we call it a planet or not, it remains and will continue to remain what it is. An astronomical body in the outer solar system, that sometimes comes closer than Neptune to Sun. Does Neptune care whether we call Pluto a planet or not? Well, no, it is too big to care.
Now, let us get back to the basic definition of ourselves. Life. What is a living being? By definition, it is an entity that is living. So what is it like to live? The ability to grow, adapt, respond and reproduce. So living beings grow, adapt to their surroundings, respond to stimuli and multiply by reproduction.
So far so good. Now, if I write a computer program that grows in size as it gathers more information and learns to map complex input to output, can adapt to different types of input, can respond to user interactions and other network stimuli, and can reproduce with other similar programs to create an even better one, does that make that computer program a living being? Will that computer program have life? Is it living? If so, can it then be regarded as a person? If so, can it have fundamental rights guaranteed by our constitution? In that case, terminating that program amounts to killing a person? A crime?
To do away with this ambiguity of granting a computer program the rights of a person, assume that the definition of life is altered to restrict it only to entities having biological processes. So then, by definition, a computer program, being a digital process, cannot be termed as having life. But wait, for an entity to be self aware and to have cognition, does it matter whether the process is a biological one or a digital one?
Today, the advancements in technology have allowed us to substitute vital organs with their artificial counterparts – like artificial limbs, pace makers, etc. In the future, the technology will become even more perfect, and we may have exact artificial replacements for natural organs. Imagine one day, we end up having artificial brains that can replace a natural brain. All the neurons and connections in a person’s brain are replaced with their digital equivalents. Will that person who has received an artificial brain transplant cease to be a living entity? If that person still continues to be considered a living person, then a computer program with similar cognitive abilities can be termed a living person as well. Isn’t it?
So we see that things are now getting more complex than simple definitions. It is not just about altering definitions or the way we define things. It is becoming more about, the way things really are. Irrespective of whether we define a computer program with cognitive abilities and awareness as a living person or not, the program has the ability to provide all reasons and to make all arguments that support its case of it being classified as a living person, and be granted all rights and liberties that a person can have.
So, finally, it is not about definitions any more, it is about what the entity being defined has to say about it being defined this way or that?
The computer program can point out to the hollowness in the definition of life. For instance, viruses are generally not considered as living entities because they cannot replicate outside their host cells. But then, we also have few bacteria like chlamydia and rickettsia that can replicate only inside host cells, just like viruses. And yet these bacteria are classified as living beings, while viruses are not! How confusing?!
Do we really need definitions then? Well, we certainly do, because that is how we categorize stuff and that makes us easy to learn and relate things. But what we should understand is that nature has no such distinct boundary that are generally intended by our definitions. In nature, systems and attributes are continuous, hence there always will be border cases when we try to define things. That is the reason, even though we like science to be compartmentalized into Physics, Chemistry and Biology, we still have to deal with Physio-chemistry, Biochemistry, Biophysics if we want to study stuff that lie on either side of the borders of our otherwise well defined boundaries. That is the reason why viruses exist as a transition from inanimate to animate stuff. That is the reason quantum world is a transition from probabilistic wave world to deterministic particle world.
So, the next time you are in confusion, have a look at the definition, just in case