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Science, Knowledge and Belief



By Rafi Moor





Scientific knowledge and belief are two complementary, inseparable and essential parts of our view of the world. Yet it is important to distinguish between them. There are different tools to handle each one of them.



Why are we asking why?

It was an October evening. A wonderful sunset inflamed the sky, coloring it with every possible shade between orange and purple. I was standing on the road in front of my house; my three year old son was sitting beside me on the hood of a parking car. I've seated him there to let him see the sunset; He was just shorter then the weeds on the roadside.

"Why did you put me up here?" He asked.

 "To let you see well." I replied.


"We wanted to see the sunset, didnít we?"


"Because it's beautiful, isn't it?"

"Why is it beautiful?"

"Look!" I said. "The sky is all red. Donít you like it?"

"Why is it red?"

"Well, you have those red sunglasses and when you wear them everything looks red, right?"

"I'm not wearing them now."

"No, but when the sun goes down we look at it through a lot of air. The air is like the sunglasses."

"Why is it going down?"

"Actually it isn't really going down, the Earth is turning and it looks as if the sun was going down."

"Why is it turning?"

Ö"I don't know." I had to admit.

"You don't know?" He asked, not as surprised as I expected.

"No." I said.


We start asking why as soon as we discover this magic word. After a while we find out that the answers we can get from our parents are very limited and we start searching for other sources of answers; but we never stop asking. We are born curious and remain curious as long as we live. Different people are interested in different things, but curiosity is a major motive common to all of us.

Curiosity might have killed the cat, but there must be something good for survival in it, otherwise natural selection would have eliminated this property from living creatures. Everyone who looks at animals can see that almost all animals of the more developed species are curious, not only dogs and cats, but also birds and rodents.

What is the contribution of curiosity to our survival?

Curiosity motivates us to learn about the world and its rules. It makes us more prepared to face new situations. By rolling stones down a hill and watching them, for instance, we learn that they take the shortest path down. If we later face a stone rolling towards us, we know that moving aside would be a better idea then running down the hill.

But curiosity is not limited to things that might be practically helpful. Researching the elementary particles and the farthest parts of the observable universe as well as philosophical debates about metaphysics and esthetics, have very little to do with survival. How can nature justify the desire for answers of this kind? The answer to this is that evolution is not a process of designing the best possible solution but a process of selecting the best from things that are randomly created. If a property is not too harmful for survival, it might remain in living creatures. A creature that is more curious than necessary has a better chance to survive than a creature with no curiosity at all.  Just as hunger is not limited to the amount of food we need to maintain our body, the hunger for knowledge is not limited to practical information.

So, we are asking questions because it is in our nature. We just can't help it. But where can we find answers? Science looks like a good source for answers about nature. Let's see what kind of answers we can expect from science.


The limits of science

The questions what exactly science is and what is a scientific method are widely discussed in the philosophy of science. Without entering into these questions at this point, it is quite clear that science involves theories, laws of nature, experiments and observation. We can safely say that a product of science is a theory about the laws of nature that matches the results of experiments and observations. So, these three elements Ė theories, laws of nature and experiments or observations, are essential for science.

Senses are our interface with reality. They are the only way by which we can get information about reality external to ourselves. Since experiments and observations are the tools science use to check nature and reality, their results must be something we can perceive by our senses. It might be very faint and indirect evidence to what we actually want to check, like the trace of a particle on a photographic plate or the computerized image of some photons that were caught by a radio telescope, but it must be sense-perceptible.

This limits science to dealing with things from which we can get perceptible evidences. The boundaries of science are thus partly determined by the level of our technology and our knowledge of the ways by which we can get perceptible signals from reality. Such boundaries might expand with time giving us more and more to explore. But some things will always remain beyond these boundaries and will always be out of reach for science. An example to such thing is the existence of higher than 3 dimensional spaces. Since we are three dimensional creatures that live in a three dimensional universe, no signal from higher dimensional (or lower dimensional) universes can be perceptible to us.

A theory can extend beyond these boundaries, but then it cease to be a pure scientific theory. There is no way to confirm or refute it. This doesn't mean that scientists don't deal with subjects and theories that are not purely scientific. There is no reason why they shouldn't. But it is important to distinguish between the things.  

These boundaries also form an upper limit to our knowledge. At any point in time we most probably donít have all the information about nature that we are able to get, and we most probably donít have a satisfactory theory about all the information we possess, but we surely don't have any knowledge about what we are not able to get any perceptible evidence of.


Laws of nature

How does science work? I have already said that science develops theories about laws of nature, so first we have to understand what a law of nature is. It is quite clear that a law is some kind of a generalization, but not every generalization is a law. "Everybody here is seated" is a generalization but it is clearly not a law. An effort is made in philosophy of science to distinguish between laws and non-law generalization, but it seems to me that there is no definite distinction between them. "Everybody here is seated" is not a law because it is not general enough. It is only locally true. It is local in time and local in space. We usually think that laws of nature are not local in time or space. Yet, we can never know it for sure because all our knowledge is local in time and space. Many laws and theories turned out to be in some way local.

"Things thrown in the air move in a parabolic path" can be considered a law of nature as long as we talk about a small enough range, so that the earth can be considered flat and the gravity field can be considered uniform and parallel. On a larger scale the trajectory would be elliptic according to Newton's law of universal gravity. But this law is not so universal either. It is true only for relatively low velocities and weak gravity fields. For higher velocities and stronger gravity fields the equations of general relativity show a much more complicated course.

So, instead of trying to distinguish between non-law generalizations and laws, we can say that the more general, the better a law is.

Another criterion is the simplicity of a law. We still use Newton's laws and not relativity whenever possible. They are much simpler and easier to use. So, for laws of nature it stands also - the simpler the better.

Science searches for order in nature. This order is described in what we call laws of nature. Science tries to find the best laws possible, that is, the most simple and general description of the behavior of nature.

Kepler's laws describe the motion of planets exactly the same as Newton's laws. But Newton's laws are both simpler and more general then Kepler's laws. While Kepler's laws describe only the motion of planets, Newton's laws describe all the dynamics of bodies. So after Newton's laws had been introduced, Kepler's laws were not needed anymore.

Ideally science would eventually find a set of simple equations that describes everything in nature. But this is not likely to happen. As we go further from our everyday experience in size, speed or time, things get more and more complicated. We need higher mathematics to write the rules and we have difficulty in comprehending the meaning of what we can mathematically describe. We need familiar models to help us understand it.

We live in a reality that is most probably infinite. Time and space are infinitely large and can be divided to infinitely small fractions. The amount of information about such a reality must be thus infinite too. It is hard to believe that a finite set of laws can describe everything in this infinite reality. Several times in the history of science we found out that what we thought was an ultimate law of nature, was after all only an approximation to a more general law, and the approximation was only good enough for certain conditions. I find it reasonable that as we go on exploring reality further we shall continuously discover that our knowledge about its rules is partial and local.


The belief

There is a debate in the philosophy of science whether science explains nature or only describes it. Clearly, laws of nature are only descriptive. They describe by words or by mathematical equations the rules and order of nature. They give an answer to the question how things happen in nature, but they don't answer the question why things happen this way. This descriptive knowledge of nature is enough for any practical purpose, but curious creatures like us are not content with this kind of knowledge. We also want answers to the question why.

The question "why" is about reason. Reason is not something that exists in nature, at least not in a way that we can perceive by our senses. Reason exists in our minds, in our thoughts. It is beyond the boundaries of our possible knowledge about nature. What tools do we have to deal with what lies beyond these boundaries?

What lies beyond our knowledge is the domain of belief. Dealing with things of which we cannot get any perceptible clue is totally subjective. There is no objective way to judge a belief. It is true as someone believes it and it is true for the one who believes it. Most of the issues that philosophy deals with, including everything that is written in this paper, are about beliefs. As I define it, science is descriptive and is about knowledge. Philosophy, or more precisely metaphysics, deals with meaning, reasoning and being, and is about belief.

The questions why things happen and what things really are - questions that are widely discussed among scientists - are actually philosophical question and as such do not have a single objectively true answer.



Theories usually try to explain things, not only describe them. That makes theories partly scientific and partly philosophical. The scientific part of a theory is usually not a subject to debate. This is the descriptive part of the theory and is about how it fits the perceptible reality. The hard arguments are usually about the philosophical part of theories. About what it means and about what things really are.

Einstein said in his theory of general relativity that gravity is a curvature in time-space and not a force field. Though Einstein started with this assumption, found the equations on purely theoretical basis and the observations and experiments that verified it only came later, the only thing that we can scientifically determine about this theory is that the equations seem to be correct. Though it is hard to see how anyone could get to these equations in a different way, it is equally correct saying that gravity is a force field that behaves differently than electric or magnetic fields. Any other explanation that suit the mathematics and does not have logical contradiction in itself would be correct too. The fact that Einstein's explanation makes sense to us is subjective and depends on how our brain works. It means nothing about how real or true it is.

Things make sense to us if they fit to what we use to think is true Ė to our paradigm. Not so many years ago, a thought that the earth is round or that it is not the center of the universe did not make any sense to anyone. One of the longest and hardest debates in the history of science was due to such patterns of thinking. It was about the question whether light is wave or matter. The supporters of each side fought hard for their ideas and put a lot of effort in trying to prove them. The simple answer to this question is that light is neither wave nor matter. It is just a different thing that has some cyclic properties similar to those of waves and some dynamic properties similar to those of matter. Even the complex explanation of the quantum theory,that says that it is potentially both wave and matter and it turns to be one of them as we measure it, is not necessary. The whole debate came from the assumption that light had to belong to a known category. Establishing a new category for things like light is not easy for us. It means reducing generality and simplicity of our knowledge about nature. But as Einstein once said: "Everything should be made as simple as possible, but not simpler".

Many scientists find the quantum theory a bit problematic. This is not because its laws are not general or simple enough, but because they are not definite. They cannot predict the behavior of things in nature, but can only predict the probability for each one of the different possible behaviors. Most scientists agree about the validity of the laws and equations of the quantum theory. They are supported by many experiments and observations. But the thought that there is no one definite way in which things can develop from one situation to another is incompatible with the scientific outlook. What bothers even more is the interpretation given to the theory. It says that things do not have a definite state before they are measured or observed. They are in some superposition of all the possible states they can have and this superposition collapses to a single definite state only as we measure or observe them. It actually means that reality depends on our perception of it. Ervin Schrödinger, one of the founders of the theory, described once a (rather cruel) hypothetical experiment to show how absurd it looks when we use such theory for our everyday life and not for tiny invisible particles. He suggested the following scenario: A cat is locked in a sealed metal box with some atomic device that has fifty percent chance to lethally poison the cat. We have no way of knowing whether the cat is alive or dead until we open the box. According to the above theory, as long as the box is sealed the cat would be in a superposition state in which it is both dead and alive. Only when we open the box it turns to one of the states.

This looks completely unreasonable to us. We have never seen a cat that is both dead and alive. But on the other hand, we have never seen a cat when we can't see itÖ

The questions how things are when we don't observe them, is the ultimate example of something that is out of our possible knowledge limits. There is no way we can get any perception of something that we donít perceive. The question is thus philosophical and not scientific and the answer depends on our belief. The superposition theory is exactly as true as the theory that claims that things are in one of the possible states when we don't observe them, only we can't know in which.


The importance of beliefs

The reader so far might have got the wrong impression about the importance of philosophic theories and beliefs. As opposed to scientific knowledge they are subjective and undetermined and have little or no practical value. But philosophical issues and beliefs are not only complementary to scientific knowledge; they are also the foundations upon which science is built. We must have some premises, some assumptions that cannot be verified or checked, to start with. Without philosophy and belief science could not exist.

First we need the belief in the existence of an objective reality that is perceived more or less the same by everyone. This assumption is the fulcrum of science and knowledge. Without presuming that, there is nothing much to explore or know.

There were many attempts in the history of philosophy, from the skeptics in ancient Greece through Descartes to the physicists of the quantum theory, to doubt this assumption. Descartes, for instance, tried to base all knowledge on a more solid fulcrum: "I think therefore I am". I know that I exist because otherwise I couldn't be thinking. I don't need any assumptions or beliefs to know this. This looks like a very good starting point for building knowledge. The only problem is that it is a dead end. The information about my own existence is internal to me. It tells me nothing about external reality. In order to know anything about external reality I still need my senses to get the information for me and there is no way I can know that they don't deceive me; I can only believe it. In his second step, Descartes tries to conclude that he is a thinking creature. But he immediately understands that this cannot be concluded just from knowing that he exists and is thinking. The term creature is already taken from reality that he knows from his experience. Reality he perceives by his senses; reality in which creatures exist. Descartes needs a few assumptions that are not deduced from this starting point in his curved way to prove the existence of external reality. There is no way to continue from Descartes' starting point to external reality without going back to assumptions and beliefs.

Apparently, also the quantum theory denies the existence of an objective reality. According to the theory reality depends on our perception of it. Only when we measure or observe it, it gets a certain form. But if we take a better look at it we can see that this does not deny the objectivity of reality, even for those who accept and believe this interpretation of the theory. The superposition is also a state of things in reality. Everybody who believes it exists agrees that this is the way things are when nobody observes them. This doesnít break the objectivity of reality. Also, nobody suggests that two different people read the same measurement differently. Reality is perceived the same by everyone. But what happens if one person is observing an object and another is not? Is the object in a definite state for one and still in the superposition state for the other? Is reality different for the two? No, it is not! Once an object collapsed to a definite state it cannot collapse to a different state for anyone else. The information about the object's state can be passed from one to another and it must be the same for everyone. We can only believe that objects are in superposition state when no one is observing it. Believing in this interpretation of the quantum theory does not contradict with the objectivity of reality.

So, a belief or assumption of the existence of objective reality is essential for science. Other assumptions we need are that there is an order and consistency in nature, that there are rules to its behavior, and that if a certain behavior repeats itself many times it will most probably recur in all cases. Without believing in these assumptions there is no meaning to science, laws of nature, or anything we know about the world.



Science and belief are two complementary, inseparable and essential parts of our view of the world. Yet it is important to distinguish between them. There are different tools to handle each one of them.

From time to time I hear about someone who claims to have a "scientific proof of the existence of God". This man, I think to myself, has no idea what belief is or what science is. Religion is an interpretation of what we experience or a premise according to which we interpret what we experience, but it is by no means a part of our experience. As a belief it is unprovable by definition. Science, on the other hand, does not deal with beliefs; they are completely out of its scope.

Scientists too mix the two from time to time. They frequently try to find a proof to the philosophical part of a theory. They also loose their objectivity in looking at things sometimes because they believe in a theory. They refuse to accept anything that does not fit their theory. Such scientists hold science back instead of helping to develop it.

It is very hard for anyone to change his beliefs. Max Planck once said:

"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grow up that is familiar with it."

But science should be always objective and open to changes and new ideas.