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  • Writer's pictureSiddharth Srivastava

Science and Incertitude

Updated: Jun 16, 2020

"Skepticism and wonder are the two uneasily cohabiting modes of thought that are central to the scientific method" - Carl Sagan


A lot of the people I interact with (including friends and family) question the scientific method, particularly citing the things that science "can't explain". After some thought, I realized that most people are uncomfortable with ambiguity and uncertainty -- a central part in empirical science. Richard Hamming once said that "great people can believe and disbelieve at the same time". It is this ability to handle ambiguity and uncertainty that I wish to talk about. I hope by the end of this post, I convince at least some of you that scientific thinking plows through the nonsense in a way that no other method of thinking does. Undoubtedly I falter in places, but it's the big picture that counts, and hopefully, that big picture is lucid.

Medicines work, cars move, and airplanes fly. I am not going to speak about the contribution of science in society. If its prevalence and miracles(?) (at least in the form of technology) aren't obvious to someone, a blog post by a 20-year-old will do nothing for them. In this piece, I want to speak about what I feel is the central element and the biggest weapon of science: uncertainty, doubt, and relentless skepticism. There are many factors of good science, but I want to talk about uncertainty, doubt, and skepticism since these are things that we often associate with alarm bells and apprehension.

I can say nothing that a practitioner of science wouldn't already know. I'm sure that Feynman and Sagan and many other scientists can and have described these ideas much better than I can. In fact, I'm sure 17th-18th century philosophers would recognize the ideas here too. Why repeat all of this then? Because there are great ideas developed in the history of humankind, and it's imperative that these ideas last. A steadfast and clear exposition of these ideas from generation to generation is vital to their survival. Many ideas have become common knowledge today without their critical evaluation. It's important to describe these again and renounce/appreciate them.

I am going to talk about (inexhaustively) the several hot-spots where uncertainty is engendered and propagated in each stage of the scientific method. I wish to describe the role of uncertainty in the following order, which can also be interpreted as multiple ways of thinking about science itself: application (technology), ideas (body of knowledge), and the method of doing science itself.

Applications (Technology)

The application of the scientific body of knowledge leads to devices, gadgets and the level of abstraction that can possibly be beneficial to society. When people say scientists should be careful about their work, they actually mean scientists should be careful about the applications of their work. The study of atoms is not dangerous, the bomb that we make with that knowledge is.

This is the first important level of uncertainty. The question of technology. Recently, this was epitomized by the invention of CRISPR-Cas9, a technology that can enable (crudely) cutting and pasting of DNA in organisms altering their genome at once. Jennifer Doudna, one of the co-inventors behind the science (essentially enabling precise gene editing) of CRISPR actually spoke against its use as a prevalent technology (at least till we can be sure about its thorough implications). Medicines can have side effects, space shuttles can crash during landing, and nuclear reactors can wreak chaos. This is probably the most difficult manifestation of uncertainty that a scientist can go through. The exact implications of paradigm-changing work, cannot be predicted no matter the amount of Nobel Prizes or the strength of your prediction machine. But the reason why this is the most inimical one, is because saying that this is a scientific problem is an exaggeration. It is actually a humanitarian problem, probably the most important one. It is our collective responsibility to decide when, and if, humans would want a gene-editing technology that could have an impact on future generations of our species, or what kind of a future we want when/if we actually end up making superintelligent machines.

Decision-makers (politicians, policy-makers, etc) and the general public are usually just concerned with this level of uncertainty in science. Let me delve deeper.

Ideas (Knowledge)

This is why most scientists work. To contribute to the ever-expanding and humongous body of knowledge that we acquired over centuries. It is simultaneously the most exciting and the most daunting thing imaginable. To be at the forefront and represent humanity's collective knowledge is a task not to be taken lightly. The accumulation of knowledge and the excitement that it creates is incredible. Imagine knowing that your body, an intricate web of biochemical processes and anatomical marvels, is just a carrier of information and nothing else. All we have to show for our collective history is in each one of our bodies. Information that can be read, quantified, mapped to functions. Information that shares its fundamentals with a machine that we made, and today we are fervently working towards imparting this machine the same information so that it can act and make decisions (probably better) than us. If it sounds magnificent, imagine being a scientist who gets to pull a chair, have a seat, and claim that you're contributing to the advancement of knowledge that not only shapes our understanding of the world, but also the exact nature of our society.

"Great job, scientist!", you say. "How do you go about doing this?"

It really is a beautiful thing that our universe is (mostly) reducible to a set of rules or laws, and even more astounding that these rules can usually be represented in all their glory in just one language - mathematics. How do we come up with these rules? We guess.

The famous 'turtles all the way down' hypothesis is a guess. It claims that the earth sits on the back of a turtle. Where does the turtle sit? On top of another turtle and so on ad infinitum. This is a good, imaginative guess. Why don't we accept this as a theory?

This is where observation comes in. Observation has been the judge of all hypotheses in science. I speak about observations more in the next section, but it's important to know here that hypotheses become theories, when hypotheses are subject to intense scrutiny and experiments.

Here is where another level of uncertainty arises when you're doing scientific work. You study the work that people have done previously, and you try to guess further. But, how are you to just take their experimental results for their face value? You try and reproduce their results and you seem satisfied when you get the same results. Now here is where an example would be best to demonstrate why uncertainty arises. Newton's equations of motion are not wrong. We've seen that when we calculate the speed of the car by seeing how far it traveled and how long its journey was, we get the same reading as the car's speedometer. Experiment successful; theory accepted. It's easy to imagine that this theory must be valid for all motion no matter where you are in the universe. Nobody would blame you for making this simple extrapolation. However, do remember, the law/theory was a guess and guesses can be wrong especially when you start extrapolating. Furthermore, it's not extraordinary for experiments to be wrong, even a bit of dirt can sometimes ruin the best experiments. If they're not wrong, they're incomplete and this is what happened with Newton's equations. These equations are fine for the things we observe in motion in our day-to-day life, but to actually guess the true nature of motion of all objects in this universe on a planetary scale too, a new guess was needed. That guess was Einstein's theory of relativity. The entire concept was so discordant with Newton's, it is difficult to believe that they described the same phenomena. Now that we performed more experiments, expanding our coverage (but still possibly incomplete), we understand that Einstein's theories are right and Newton's mechanics fail at the planetary scale.

After this anecdote (which is perhaps a rare one) you may call the scientific method hypocritical. Unscientific too. But it is not unscientific, just uncertain. Even today we are uncertain. As our species advances, so does our power to experiment and observe.

Another important thing to note is the huge jump that had to be made in imagination and conception of a guess, even though it described the same phenomena at a larger scale and even though the earlier equations seemed right.

Isaac Newton (left) and Albert Einstein (right)

As you can imagine, there are many levels of uncertainty, when studying ideas even in a discipline like science which takes pride in its rigor and consistency. Namely, the line between more experiments and extrapolation for novel knowledge, the extent of our imagination while guessing and many other micro-factors that always makes an adept scientist question things systematically. This doesn't mean that the work published before us was wrong (or any form of incrimination about the scientists that came before), quite the contrary. But it gives us an idea about where to search for the next big answer.


The most important part of science is coming up with the ideas, the guesses, the laws themselves. I spoke briefly about how observation is the sole judge of which guess is right and which guess is using turtles a little too casually. The exceptions and outliers to a theory cannot be ignored, in fact, the outliers are the most important parts as they disprove whatever theory was in place. They also give rise to a newfound excitement to actually find out what is right, what is true. It's a very simple, very powerful ingredient - Falsifiability.

If my guess is incompatible with the observation, it's false. Easy. If you claim that a man in your garage just turned to wine and cheese and only you can see it happening, I cannot disprove it. But any decently educated person would know what the chances of that happening are. Here is why science is an unadulterated quest for truth, it is always falsifiable. A claim that something happened that only you can see cannot be disproved by its very nature, and therefore it doesn't even qualify to be a guess in science.

This is how science makes things work.

It is also important these guesses must be as specific as possible. If I claim that my body is filled with some stuff that makes it work, it does us no good (even though it is right). If I tell you about the various organs, and the exact chemical processes that engender anatomy and physiology, it enables us to use that knowledge to actually do something. More specific the rule, more powerful it is in understanding and predicting. (Note that specificity also entails falsifiability).

It's important to note that your guess can be specific, falsifiable, based on observation and still fundamentally wrong (subject to fallacies). I can claim purely on observation that my golden retriever dog eats more than my labrador. This seems scientific enough to be a guess. However, I failed to tell you that I had 2 more golden retrievers than I did labradors. This must sound preposterous, but it happens all the time. "I cut my hair on Tuesday, and today I fell down the stairs, therefore....". As you can imagine some people are more prone to such fallacies than others.

At this point, I should mention that it is crazy that some people claim science doesn't require imagination and creativity. It is a very interesting kind of imagination that science requires, unlike that of an artist. The great difficulty here is to envision something that nobody before (or even in your time) has ever dared to see, that is consistent with every minuscule detail with what has already been seen and is still different from what was thought of. In this process, you are also supposed to be very far away from fallacies and false information. Furthermore, it must not be a vague proposition but specific and definite. It is not bounded by a brush or the frets on your guitar, the possibilities really are endless and so is the difficulty. Exciting, isn't it?

Even when a scientist says "I bet this is going to work", she says it with a certain sense of uncertainty. Our knowledge is bounded by what we can analyze and this is subject to observation. When we go wrong with our guesses, we systematically doubt things that could possibly go wrong and this leads us to better guesses.

Scientists are always uncertain and mistakes are ideally celebrated in science classrooms. There is no elaborate guessing without failure. It is important to recognize that we are actually always living in a state of uncertainty. We never know everything or even anything. Living like that is easy. How to get to know these things is the interesting part.

If we did not recognize ignorance or have any doubt, we would never get any new ideas. There would be nothing worth exploring. The appreciation and celebration of uncertainty in science is what makes it so powerful. I hope other fields, domains, and individual persons can learn to celebrate and harness uncertainty as well as science does (as is evident by the wonders that science has accomplished in its eternal quest for the truth - even in the most uncertain territory).

As for any person unfamiliar with the scientific method of thinking, I hope you find that this process of critical thinking, systematic evaluation, joyous curiosity, and skepticism can not only lead you closer towards the truth but also help you detect baloney when you come across it.


This page is highly regarded as the inception of the evolution theory - one of the biggest achievements of science. The 'Tree of Life' is the first-known sketch by Charles Darwin of an evolutionary tree describing the relationships among groups of organisms.

At the top of the page, Darwin writes two words demonstrating all that I've said till now.

"I think". Uncertainty truly is the driver of good science (along with several other factors but that lies outside the purview of this post).

Similar language and an "It seems to me...." every now and then is observed in Einstein's paper on Relativity signifying some level of uncertainty.

Doubt and uncertainty even with all the evidence and consistency is the key to good science. No matter how big or small the scientific work is deemed.

As Carlo Rovelli put it, "Genius hesitates".



Many thanks to Erin, Aadrika and Preity for reading the initial draft and providing their feedback.

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