Statistics and P value

The How Science is done? (previous article) mentions the Scientific Method. One of the most important steps of this algorithm is formulating a hypothesis, a statement that will undergo validation by design of appropriate experiments.

To validate our hypothesis (alternate hypothesis), we make a null hypothesis. Let’s go with an example again.
The desert area outside West Texas is famous for Marfa Lights which are basically glowing orbs of the size of basketballs. For quite a long time, people were scared of the sight when suddenly glowing gas balls appeared in the midst of air. Local university students thought that they were caused by the car headlights passing along the US Highway 67. Now how does one check this hypothesis.
Let’s give it a try.
Here, the alternate hypothesis would be “Marfa lights are caused by car headlights” and the null hypothesis would be ”Marfa lights are not caused by car headlights”.

Now to validate our hypothesis, we can design an experiment to reject the null hypothesis.

Experiment: “Calculate the number of cars on the US Highway 67 and calculate the number of Marfa lights observed.” Now if this experiment is done just once, we cannot conclude anything about our null hypothesis. The experiment results would vary on a sunny day or on a foggy day. Also, it may simply be possible that you turn out to be lucky to get the number of cars equal to the number of Marfa lights. Thus to make a more precise conclusion, it is essential for the experiment to be repeated several times. Exactly many times depends on the nature of experiment, the error bars involved and the analyst in question.

Suppose that the experiment has been repeated several times, maybe 5 times a day over a year. This would be an enormous data.
Now if our null hypothesis were true, the data obtained from these experiments would fit well with the expected data. The expectation would be that the number of car lights and the number of Marfa lights have a significant difference. Here is where statistics comes into play.
What do we mean by significant?

To answer such questions, statisticians have devised excellent methods to analyze data. Based on the null hypothesis and a significance level determined (like 5% significant or 1% significant), the data generated by experiments or observations is cross-verified against this significance level and something called a p-value is generated.
P-value is nothing but a probability value obtained from the distribution function that fits the expected data.
A significance level is a percentage below which the data is supposed to not fit this distribution function. Usually, a significance level of 0.05 (meaning 5%) or 0.01 (meaning 1%) is chosen, but it really depends on the needs of the test and the analyst. So if the data lies below the significance level, we can reject the null hypothesis, however, there exists a probability of (p * 100 %), (where p is the p-value for the given data) that the null hypothesis may be true. Now suppose that the p-value for the data lies above the significance level. One would assume that the null hypothesis is true. However, that isn’t the case. All we could say is the alternate hypothesis is not true.

In short, there exists no method to truly accept or reject the alternate hypothesis. All that is possible is to verify it to a certain significance level.

These statistical tests are very strong if used wisely. However, most of the times, they are not used properly. This leads to something called p-hacking, which I will address in my next blog.

References:
1. The Manga Guide to Statistics, Shin Takashi
2. What are Marfa Lights
3. 3 Times Science Debunked the Paranormal, SciShow

How Science is done?

One of the things that makes humans so special is probably their curiosity, the urge to know, to observe phenomena, to pose questions and above all trying to answer them. Science is one of the ways devised to answer these questions in a systematic and rational manner.

To begin with, I will introduce scientific method. Everything that scientists do can be roughly formulated into an algorithm called the scientific method. I will try to make it more clear using an example.

The first step is to “observe” some phenomena. Observation requires alert mind and constant vigilance. Observation basically includes anything that answers a question “What?”
For instance, we observe that everyday sun is rising in the east (maybe for 20 years of your life and you also know it from historical reports say of at least a few hundred years).

To make sense of it, one then makes a hypothesis, which is basically an answer that may explain the phenomena. This is an important step. It is essential for the hypothesis to be “falsifiable”: meaning that one should be able to disprove the converse of the statement. For instance, the statement that “Sun daily rises in the East” could be a valid hypothesis. Understand that one cannot prove this statement. To prove the statement the observer has to observe the Sun “daily” which is impossible for a normal human being. What can be done instead is to disprove the converse: “Sun doesn't rise in the West”. As far as we don’t see Sun rising in the West provides us with evidence to support “Sun daily rises in the East”. Stronger and increasing shreds of evidence, convert a hypothesis into a fact, a theory. However, a single valid observation of Sun rising in the West is enough to disprove the statement. Generalizing it, one can clearly see that there is nothing called a proof in Science (except maybe in Mathematics where you can provide definitive proofs).

Based on the hypothesis, predictions are made which can then be tested using experiments or analysis or a model can be built that suits well with the data. Experiments are then repeated and reformulated. New predictions are made which are further tested. All of these provide pieces of evidence supporting our hypothesis, never proves it. A single experiment giving a negative result simply crushes the hypothesis or causes it to be restated.

A well-supported hypothesis becomes a theory, a fact. This gives rise to new observations and the cycle continues.

The cycle appears quite simple. However, it does not really take into account all the aspects of “How Science is done?” It does not provide an answer to “What does a Scientist do?” Science like other disciplines requires a lot of hard work and patience. Apart from these steps (mentioned above), a scientist also plays with various parameters. Many experiments fail not because the hypothesis was false but because of errors in instrumentation, in handling and many times, the sources of these errors are difficult to find out. The results appear simple and interesting, but the work done before arriving at it is mostly unknown. The frustration, the excitement, the competition among labs to arrive at the answer first, the politics behind are hardly even recognized.

Why Love?

Emotions drive us throughout our lives. The feeling of happiness on receiving a packet of chocolate, feeling guilty on committing a mistake or sad on losing the grade you expected, ….. One of these emotions is the feeling of love. Humans have experienced this for many generations, and a lot of philosophers, psychologists, and even scientists have tried to understand the exact nature of love. But still, a lot remains unknown about this almost magical state.

So what exactly is love? According to Merriam-Webster’s Dictionary, Love is a “strong affection for another arising out of kinship or personal ties.” Romantic love is a warm and pleasurable sensation that is associated with but does not necessarily lead to sexual attraction.

It is a common belief that love arose from Western Culture. However, stories of love have been widespread across various cultures throughout the globe. Do animals also love the way humans do? It is not clear if animals experience the same kinds of emotions as we do, but the brain circuitries associated with the sensation of love in humans have prototypes in other mammalian brains. Studies have shown that dogs are attached to the owners not just for food and shelter, but they indeed exhibit the feeling of attachment and compassion. Other studies have also shown that animals also feel same for others of their kind.

The most striking question that follows up then is “Why on earth do we love?” Plato, an ancient Greek philosopher, argued that love makes us complete. It is a search for finding our true soulmate. Schopenhauer asserted that it is a trick of nature. The feeling of love brings two people together which gives rise to the sense of lust and ultimately separates them by producing children. Ultimately, the individuals are tricked into love to ensure that they propagate their genes.

Chimpanzees, our closest relatives, mate mainly when the female reaches her estrus. The olfactory cues and genital swellings provide them with the indications. In humans, however, ovulation is practically concealed. Except for minor changes in the physical appearance of a female (a slight glow of the skin or an increase in sexual desire), there are no indications of her ovulation. Mating then expanded over the entire menstrual cycle. This was a massive investment in the resources by both males and females. Long-term bonds were thus favored, which resulted in commitment-based relations. This explains why our body needs to expend resources on making us give the feeling of love. It has also been observed that falling in love brings about behavioral changes in the individuals.

Love then plays the role of ensuring a healthy relationship and thus healthy offsprings. However like other emotions, love too is fluid. Parting away from partners is observed to bring a suppression in the activity of the brain areas associated with the feeling. Also in some cases, other behaviors are affected which may trick the individual into depression and loneliness.

Whatever may be the reason for why we fall in love, but each one of us has a unique experience of our love. It could be an adventure or could be heartbreaking or even the best thing in your life!


References:
1. Ted Ed: Why do we love? A philosophical inquiry - Skye C. Cleary
2. http://www.youramazingbrain.org/lovesex/sciencelove.htm
3. Ted Ed: What is love? - Brad Troeger
4. The Evolution of Love, David M. Buss
5. Why We Love?, Helen Fisher
6. Wikipedia
7. https://www.psychologytoday.com/blog/the-mysteries-love/201402/can-animals-love

Science and the threat of Scienticism

Today we live in a world where the powers of mantras and prayers have diminished in their strength, to be taken over by logic and reasoning. We are now in the world of science, where questions that were earlier thought of as being unanswerable or having divine origins are currently being poked using the algorithm of “scientific method.”

Understanding nature has been one of the curiosities for early men. Pondering over the daily phenomenon and learning through experience with knowledge passing down the line, humans tried to gather information about the world predictably. Curiosity flavored with logic gave rise to Philosophy whereas fear backed by the necessity of a divine power ended up in Religion. Then the need to clarify and provide pieces of evidence offered a way to experimentation, and the field of Science emerged. Sometimes supported, sometimes opposed by the former two fields, science has entered in its full glory into the 21st century.

Science is neither good nor bad. Science is merely a process of gaining knowledge, understanding the world. What could be good or bad is the application of this acquired knowledge: the technology. With “science” being a buzzword today, people often end up blaming the scientists for the evil technological applications of their work. The problem becomes particularly more serious when the very “textbooks of science” ignore the difference. However, I am not going through this in my present article.

What I want to press on is a more severe problem of “Scienticism.” Scienticism is basically a belief, prevalent not only among commons but also among scientists, that the answers given by science are always true and hence to be believed upon. However, science doesn’t necessarily always provide answers that are true. To put it straight, science never “proves” anything. What it does instead is to prove that the converse of the statement is false. Hypotheses become theories when backed up by evidences. However, theories may fall off. A single evidence that reports a flaw in the theory breaks it down. Newton’s Gravitational Theory was supported by experimental evidence for over 200 years until Einstein came up with his General Theory of Relativity to address the flaws.

Crudely stating, science is malleable. Scienticism ends up the very nature of science to be plastic. Science is not about finding the answer to a problem but about finding an answer that is closest to being accurate. Perhaps this is what makes science beautiful and unique of its kind.

Scienticism could be thought of as superstition in its new form. Eradicating it is a need of today.

References:

1. http://www.intellectualtakeout.org/blog/science-scientism
2. https://www.al-isam.org/islamic-thought-book-one-muhammad-saidi-mihr-amir-divani/introduction-religion-modern-world#scienticism
3. Wikipedia
4. What is Theory? Jim Stewart, Victoria Harte and Sally Sambrook

Homo fictum

The story begins with a group of hunter-gatherers around 70,000 years ago when they set out from Africa to explore and settle themselves all over the world. Somehow their time of landing appears to be highly correlated with wiping out of many species from these lands. In this period (between 70000 - 30000 years ago), a large number of changes happened in their societies and culture.

Of the many changes that happened, the one that would change them entirely was the development of language: a means to communicate. But wait! All animals, plants and even bacteria communicate. In fact, higher animals like some insects, birds, and mammals have also evolved to use sound as a means of communication. Then what makes the human language unique? The answer is structure. Human language has a well-defined structure. A limited number of sounds can be connected to create many words which can then be joined in many different ways to form complex sentences.

Humans could now express their experiences with words. They could tell their group members what food is good, who is cheating whom and what do the neighboring tribe members do. Social learning was taken altogether to a new level.

The power of language, however, is not in this expression of memories but in passing down knowledge about things that don’t exist at all. The food that can’t be eaten could then be said of being evil. The natural phenomenon could be given divine powers. Myths, gods, demons, prophecies started to appear. What good could this be? After all, people who are going to spend hours with gods and demons or go out in search of mythological objects are going to get a small hunt. They and their families will strive and thus have a lesser chance of passing down their genes.

However, imagination also allowed with something more: to dream in groups. The tales began to spread across tribes, and people who believed in similar things started uniting in groups. A typical human can maintain healthy contacts with about 150 other humans (Dunbar’s number 5, it is based on the data from primates and extrapolating it to average human brain size). However, when it comes to same ideology, people can unite under one flag without needing to know each other. The flag of divine power, of being in the same tribe, of being in the same country and of being a human. The cognitive limit exceeded the biological constraints. Today we all coexist just because we all believe in this flag of humanity. This gave us the power to rule: rule over the weaker, the animals who can’t unite in such huge numbers.

Today’s world in which you and I live could all be accounted for this leap of fiction. We believe in gods, in nations, in human rights all of which don’t exist physically but are somewhere in our minds. It gives the power to unify. People working in companies can believe themselves to be a part of something big: an emblem. Institutes, colleges, nations, governments, laws, and society all work because their members have faith in them.

It’s incredible, right? We all work and live our lives for and with things that don’t exist! More strange is that we talk about these objects as being a part of the world. Ascribing to them existence!

References:
1. Sapiens: A Brief History of Humankind by Yuval Harari
2. http://whoami.sciencemuseum.org.uk/whoami/findoutmore/yourbrain/whatisspecialabouthumanlanguage
3. Wikipedia
4. Britannica
5. Dunbar (1992) "Neocortex size as a constraint on group size in primates"

Real or Not real?

    Reality - “it feels so real”, “it is obviously real” - we all hear of it but hardly think of it deeply. But wait! The real world to us is merely brought to us by our senses, right? The flower we see in the garden is only an interpretation of the sensory receptors in our eyes, processed by our brains. The smell of it, the sounds of birds all are brought to us by our senses. Thus we interpret the world using our senses. Then, the world that we perceive is merely the overall sum of all these interpretations.

Does that mean that the world is all there in our brains? Or maybe the reality exists but what we perceive as “our reality” is merely just a small part of it? (Phaneron)

    Let’s begin with senses first. We have the standard five senses that we know of (sight, smell, touch, sound, taste); but in addition to these, we have many other(2) like proprioception (the sense of space), kinesthetic sense, nociception (pain) and many more. They bring to our brains the signals from the outer world and our brain processes the signals to give us a feeling for the sense. And as we all know, these senses are not accurate. Optical illusions, the hotness-coldness experiment we did in our schools to get a sense of what temperature is provide a glimpse of how wrong these senses can go. Moreover, we also know that we don’t sense everything out there. Our eyes can detect only a small spectrum of the electromagnetic radiation (visible light), our ears can hear just those sounds lying in the frequency range of 20 - 20000 Hz. Thus clearly we cannot perceive the world merely with our senses. The reality for me then is just a small part of what exists and what can be sensed by my senses.

Now the question that arises is: Is my reality the same as yours?

As we discussed earlier, we perceive only a small part of the world. And we very well know that the senses of all animals have evolved over the years to fit their needs. The dogs and whales can thus smell more distinctly than we could. Therefore a garbage pile would smell filthy to you and me, but there would be many odors for the dog to sniff there. The reality for dog and us is different! Strange right?

What about within humans? Do all humans perceive the world in the same way? People with color-blindness cannot distinguish between green and red. Born blind people cannot see at all. World to them is brought to their minds by auditory, olfactory, tactile     and other senses. Similarly, born deaf humans cannot hear the sounds of the chirping birds at all. Then indeed “my reality” is different from yours? Yes, provided either you or I have some problem with our senses. But what about people that have all their senses intact since birth? The problem now grows difficult. There isn’t a satisfying answer to this question.

The human brain as we discussed processes the information from the external world to give us a sense of “our reality”. However, the very connections in the brain are determined genetically and modified by learning. Thus naturally my red may differ from your red. By red, I don’t mean the property the red color has got: like it’s wavelength. That can be checked by inserting electrodes in the retina. Instead, what I mean is the meaning that you and I associate with this red: my feeling for red. How do I know that what rose means to me is the same as what rose means to you? We have now landed in the difficult problem of Consciousness. With the search of science still going on to understand consciousness, we don’t yet have an answer to our question. Here I would like to point out that I haven't even touched an even more difficult problem of “Does the world at all exist outside our brains?” probably because it’s easier and better to believe that the world exists.

Though it is not clear if my world - my reality - is different from your world but now I know that it is at least different from that of the birds that I heard chirping. It is just surprising to me how the same world, the same nature could mean so differently to different life forms. Truly mesmerizing! The world is indeed beautiful! Probably we may never know what exactly is absolute reality. But my reality - my world - is astounding: with my friends, my family and myself in it.

References:

1. Is Anything Real? Vsauce
2. https://www.livescience.com/60752-human-senses.html
3. What is Reality - The Human Brain (Documentary)
4. Wikipedia
5. Britannica
6. In Search of Memory, Eric Kandel