Relation of physics to other sciences?

Answer 1

Sociology and Psychology are overlapping in that social influences effect the psychological development of individuals. Sociology is obvious in history in that the social interactions of individuals have effected history, and then of course there is the history of Sociology itself. The study of economics in sociology is stratification, which is the study of how we are a part of a certain economic level in society and how we got there and how it effects us. Finally, political science has been studied by many Sociologists for such issues as slavery, women in politics, etc.

Answer 2

The Relation of Physics to Other Sciences

3-1 Introduction

Physics is the most fundamental and all-inclusive of the sciences, and has

had a profound effect on all scientific development. In fact, physics is the presentday

equivalent of what used to be called natural philosophy,from which most of

our modern sciences arose. Students of many fields find themselves studying

physics because of the basic role it plays in all phenomena. In this chapter we

shall try to explain what the fundamental problems in the other sciences are,

but of course it is impossible in so small a space really to deal with the complex,

subtle, beautiful matters in these other fields. Lack of space also prevents our

discussing the relation of physics to engineering, industry, society, and war, or

even the most remarkable relationship between mathematics and physics. (Mathematics

is not a science from our point of view, in the sense that it is not a natural

science. The test of its validity is not experiment.) We must, incidentally, make it

clear from the beginning that if a thing is not a science, it is not necessarily bad.

For example, love is not a science. So, if something is said not to be a science,

it does not mean that there is something wrong with it; it just means that it is not

a science.

3-2 Chemistry

The science which is perhaps the most deeply affected by physics is chemistry.

Historically, the early days of chemistry dealt almost entirely with what we now call

inorganic chemistry, the chemistry of substances which are not associated with

living things. Considerable analysis was required to discover the existence of the

many elements and their relationships-how they make the various relatively

simple compounds found in rocks, earth, etc. This early chemistry was very

important for physics. The interaction between the two sciences was very great

because the theory of atoms was substantiated to a large extent by experiments

in chemistry. The theory of chemistry, i.e., of the reactions themselves, was

summarized to a large extent in the periodic chart of Mendeleev, which brings out

many strange relationships among the various elements, and it was the collection

of rules as to which substance is combined with which, and how, that constituted

inorganic chemistry. All these rules were ultimately explained in principle by

quantum mechanics, so that theoretical chemistry is in fact physics. On the

other hand, it must be emphasized that this explanation is in principle. We have

already discussed the difference between knowing the rules of the game of chess,

and being able to play. So it is that we may know the rules, but we cannot play

very well. It turns out to be very difficult to predict precisely what will happen in

a given chemical reaction; nevertheless, the deepest part of theoretical chemistry

must end up in quantum mechanics.

There is also a branch of physics and chemistry which was developed by both

sciences together, and which is extremely important. This is the method of

statistics applied in a situation in which there are mechanical laws, which is aptly

called statistical mechanics. In any chemical situation a large number of atoms are

involved, and we have seen that the atoms are all jiggling around in a very random

and complicated way. If we could analyze each collision, and be able to follow

in detail the motion of each molecule, we might hope to figure out what would

happen, but the many numbers needed to keep track of all these molecules exceeds

so enormously the capacity of any computer, and certainly the capacity of

3-1

3-1 Introduction

3-2 Chemistry

3-3 Biology

3-4 Astronomy

3-5 Geology

3-6 Psychology

3-7 How did it get that way?

the mind, that it was important to develop a method for dealing with such complicated

situations. Statistical mechanics, then, is the science of the phenomena

of heat, or thermodynamics. Inorganic chemistry is, as a science, now reduced

essentially to what are called physical chemistry and quantum chemistry; physical

chemistry to study the rates at which reactions occur and what is happening in

detail (How do the molecules hit? Which pieces fly off first?, etc.), and quantum

chemistry to help us understand what happens in terms of the physical laws.

The other branch of chemistry is organic chemistry, the chemistry of the

substances which are associated with living things. For a time it was believed

that the substances which are associated with living things were so marvelous

that they could not be made by hand, from inorganic materials. This is not at

all true-they are just the same as the substances made in inorganic chemistry,

but more complicated arrangements of atoms are involved. Organic chemistry

obviously has a very close relationship to the Biology which supplies its substances,

and to industry, and furthermore, much physical chemistry and quantum mechanics

can be applied to organic as well as to inorganic compounds. However, the main

problems of organic chemistry are not in these aspects, but rather in the analysis

and synthesis of the substances which are formed in biological systems, in living

things. This leads imperceptibly, in steps, toward biochemistry, and then into

biology itself, or molecular biology.

3-3 Biology

Thus we come to the science of biology, which is the study of living things.

In the early days of biology, the biologists had to deal with the purely descriptive

problem of finding out what living things there were, and so they just had to

count such things as the hairs of the limbs of fleas. After these matters were worked

out with a great deal of interest, the biologists went into the machinery inside the

living bodies, first from a gross standpoint, naturally, because it takes some effort

to get into the finer details.

There was an interesting early relationship between physics and biology in

which biology helped physics in the discovery of the conservation of energy, which

was first demonstrated by Mayer in connection with the amount of heat taken in

and given out by a living creature.

If we look at the processes of biology of living animals more closely, we see

many physical phenomena: the circulation of blood, pumps, pressure, etc. There

are nerves: we know what is happening when we step on a sharp stone, and that

somehow or other the information goes from the leg up. It is interesting how that

happens. In their study of nerves, the biologists have come to the conclusion that

nerves are very fine tubes with a complex wall which is very thin; through this

wall the cell pumps ions, so that there are positive ions on the outside and negative

ions on the inside, like a capacitor. Now this membrane has an interesting

property; if it "discharges" in one place, i.e., if some of the ions were able to move

through one place, so that the electric voltage is reduced there, that electrical

influence makes itself felt on the ions in the neighborhood, and it affects the

membrane in such a way that it lets the ions through at neighboring points also.

This in turn affects it farther along, etc., and so there is a wave of "penetrability"

of the membrane which runs down the fiber when it is "excited" at one end by

stepping on the sharp stone. This wave is somewhat analogous to a long sequence

of vertical dominoes; if the end one is pushed over, that one pushes the next,

etc. Of course this will transmit only one message unless the dominoes are set

up again; and similarly in the nerve cell, there are processes which pump the ions

slowly out again, to get the nerve ready for the next impulse. So it is that we know

what we are doing (or at least where we are). Of course the electrical effects

associated with this nerve impulse can be picked up with electrical instruments,

and because there are electrical effects, obviously the physics of electrical effects

has had a great deal of influence on understanding the phenomenon.

The opposite effect is that, from somewhere in the brain, a message is sent

out along a nerve. What happens at the end of the nerve? There the nerve branches

3-2

out into fine little things, connected to a structure near a muscle, called an endplate.

For reasons which are not exactly understood, when the impulse reaches

the end of the nerve, little packets of a chemical called acetylcholine are shot off

(five or ten molecules at a time) and they affect the muscle fiber and make it contract-

how simple! What makes a muscle contract? A muscle is a very large number

of fibers close together, containing two different substances, myosin and

actomyosin, but the machinery by which the chemical reaction induced by acetylcholine

can modify the dimensions of the molecule is not yet known. Thus the

fundamental processes in the muscle that make mechanical motions are not known.

Biology is such an enormously wide field that there are hosts of other problems

that we cannot mention at all-problems on how vision works (what the light does

in the eye), how hearing works, etc. (The way in which thinking works we shall

discuss later under psychology.) Now, these things concerning biology which

we have just discussed are, from a biological standpoint, really not fundamental,

at the bottom of life, in the sense that even if we understood them we still would

not understand life itself. To illustrate: the men who study nerves feel their work

is very important, because after all you cannot have animals without nerves.

But you can have life without nerves. Plants have neither nerves nor muscles,

but they are working, they are alive, just the same. So for the fundamental problems

of biology we must look deeper; when we do, we discover that all living

things have a great many characteristics in common. The most common feature

is that they are made of cells, within each of which is complex machinery for doing

things chemically. In plant cells, for example, there is machinery for picking up

light and generating sucrose, which is consumed in the dark to keep the plant

alive. When the plant is eaten the sucrose itself generates in the animal a series

of chemical reactions very closely related to photosynthesis (and its opposite

effect in the dark) in plants.

In the cells of living systems there are many elaborate chemical reactions,

in which one compound is changed into another and another. To give some impression

of the enormous efforts that have gone into the study of biochemistry,

the chart in Fig. 3-1 summarizes our knowledge to date on just one small part of

the many series of reactions which occur in cells, perhaps a percent or so of it.

Here we see a whole series of molecules which change from one to another

in a sequence or cycle of rather small steps. It is called the Krebs cycle, the respiratory

cycle. Each of the chemicals and each of the steps is fairly simple, in terms

of what change is made in the molecule, but-and this is a centrally important

discovery in biochemistry-these changes are relatively difficult to accomplish in a

laboratory. If we have one substance and another very similar substance, the one

does not just turn into the other, because the two forms are usually separated by

3-3

an energy barrier or "hill." Consider this analogy: If we wanted to take an object

from one place to another, at the same level but on the other side of a hill, we could

push it over the top, but to do so requires the addition of some energy. Thus

most chemical reactions do not occur, because there is what is called an activation

energy in the way. In order to add an extra atom to our chemical requires

that we get it close enough that some rearrangement can occur; then it will stick.

But if we cannot give it enough energy to get it close enough, it will not go to completion,

it will just go part way up the "hill" and back down again. However,

if we could literally take the molecules in our hands and push and pull the atoms

around in such a way as to open a hole to let the new atom in, and then let it snap

back, we would have found another way, around the hill, which would not require

extra energy, and the reaction would go easily. Now there actually are, in the cells,

very large molecules, much larger than the ones whose changes we have been describing,

which in some complicated way hold the smaller molecules just right, so

that the reaction can occur easily. These very large and complicated things are

called enzymes. (They were first called ferments, because they were originally

discovered in the fermentation of sugar. In fact, some of the first reactions in

the cycle were discovered there.) In the presence of an enzyme the reaction will go.

An enzyme is made of another substance called protein.Enzymes are very

big and complicated, and each one is different, each being built to control a certain

special reaction. The names of the enzymes are written in Fig. 3-1 at each reaction.

(Sometimes the same enzyme may control two reactions.) We emphasize that the

enzymes themselves are not involved in the reaction directly. They do not change;

they merely let an atom go from one place to another. Having done so, the enzyme

is ready to do it to the next molecule, like a machine in a factory. Of course, there

must be a supply of certain atoms and a way of disposing of other atoms. Take

hydrogen, for example: there are enzymes which have special units on them which

carry the hydrogen for all chemical reactions. For example, there are three or four

hydrogen-reducing enzymes which are used all over our cycle in different places.

It is interesting that the machinery which liberates some hydrogen at one place

will take that hydrogen and use it somewhere else.

The most important feature of the cycle of Fig. 3-1 is the transformation

from GDP to GTP (guanadine-di-phosphate to guanadine-tri-phosphate) because

the one substance has much more energy in it than the other. Just as there is a

"box" in certain enzymes for carrying hydrogen atoms around, there are special

energy-carrying "boxes" which involve the triphosphate group. So, GTP has more

energy than GDP and if the cycle is going one way, we are producing molecules

which have extra energy and which can go drive some other cycle which requires

energy, for example the contraction of muscle. The muscle will not contract

unless there is GTP. We can take muscle fiber, put it in water, and add GTP,

and the fibers contract, changing GTP to GDP if the right enzymes are present.

So the real system is in the GDP-GTP transformation; in the dark the GTP

which has been stored up during the day is used to run the whole cycle around the

other way. An enzyme you see, does not care in which direction the reaction goes,

for if it did it would violate one of the laws of physics.

Physics is of great importance in biology and other sciences for still another

reason, that has to do with experimental techniques. In fact, if it were not for the

great development of experimental physics, these biochemistry charts would not

be known today. The reason is that the most useful tool of all for analyzing this

fantastically complex system is to label the atoms which are used in the reactions.

Thus, if we could introduce into the cycle some carbon dioxide which has a

"green mark" on it, and then measure after three seconds where the green mark

is, and again measure after ten seconds, etc., we could trace out the course of the

reactions. What are the "green marks"? They are different isotopes. We recall

that the chemical properties of atoms are determined by the number of electrons,

not by the mass of the nucleus. But there can be, for example in carbon, six

neutrons or seven neutrons, together with the six protons which all carbon nuclei

have. Chemically, the two atoms C12 and C13 are the same, but they differ in

weight and they have different nuclear properties, and so they are distinguishable.

3-4

By using these isotopes of different weights, or even radioactive isotopes like C14,

which provide a more sensitive means for tracing very small quantities, it is possible

to trace the reactions.

Now, we return to the description of enzymes and proteins. All proteins are

not enzymes, but all enzymes are proteins. There are many proteins, such as the

proteins in muscle, the structural proteins which are, for example, in cartilage and

hair, skin, etc., that are not themselves enzymes. However, proteins are a very

characteristic substance of life: first of all they make up all the enzymes, and

second, they make up much of the rest of living material. Proteins have a very

interesting and simple structure. They are a series, or chain, of different ammo

acids. There are twenty different amino acids, and they all can combine with

each other to form chains in which the backbone is CO-NH, etc. Proteins are

nothing but chains of various ones of these twenty amino acids. Each of the amino

acids probably serves some special purpose. Some, for example, have a sulphur

atom at a certain place; when two sulphur atoms are in the same protein, they

form a bond, that is, they tie the chain together at two points and form a loop.

Another has extra oxygen atoms which make it an acidic substance, another has

a basic characteristic. Some of them have big groups hanging out to one side, so -

that they take up a lot of space. One of the amino acids, called prolene, is not

really an amino acid, but imino acid. There is a slight difference, with the result

that when prolene is in the chain, there is a kink in the chain. If we wished to

manufacture a particular protein, we would give these instructions: put one of

those sulphur hooks here; next, add something to take up space; then attach something

to put a kink in the chain. In this way, we will get a complicated-looking

chain, hooked together and having some complex structure; this is presumably

just the manner in which all the various enzymes are made. One of the great triumphs

in recent times (since 1960), was at last to discover the exact spatial atomic

arrangement of certain proteins, which involve some fifty-six or sixty amino acids

in a row. Over a thousand atoms (more nearly two thousand, if we count the

hydrogen atoms) have been located in a complex pattern in two proteins. The

first was hemoglobin. One of the sad aspects of this discovery is that we cannot see

anything from the pattern; we do not understand why it works the way it does.

Of course, that is the next problem to be attacked.

Another problem is how do the enzymes know what to be? A red-eyed fly

makes a red-eyed fly baby, and so the information for the whole pattern of enzymes

to make red pigment must be passed from one fly to the next. This is done by a

substance in the nucleus of the cell, not a protein, called DNA (short for desoxyribose

nucleic acid). This is the key substance which is passed from one cell

to another (for instance, sperm cells consist mostly of DNA) and carries the

information as to how to make the enzymes. DNA is the "blueprint." What does

the blueprint look like and how does it work? First, the blueprint must be able

to reproduce itself. Secondly, it must be able to instruct the protein. Concerning

the reproduction, we might think that this proceeds like cell reproduction. Cells

simply grow bigger and then divide in half. Must it be thus with DNA molecules,

then, that they too grow bigger and divide in half? Every atom certainly does not

grow bigger and divide in half! No, it is impossible to reproduce a molecule

except by some more clever way.

The structure of the substance DNA was studied for a long time, first chemically

to find the composition, and then with x-rays to find the pattern in space.

The result was the following remarkable discovery: The DNA molecule is a pair

of chains, twisted upon each other. The backbone of each of these chains, which

are analogous to the chains of proteins but chemically quite different, is a series

of sugar and phosphate groups, as shown in Fig. 3-2. Now we see how the chain

can contain instructions, for if we could split this chain down the middle, we would

have a series BAADC . . . and every living thing could have a different series.

Thus perhaps, in some way, the specific instructions for the manufacture of proteins

are contained in the specific series of the DNA.

Attached to each sugar along the line, and linking the two chains together, are

certain pairs of cross-links. However, they are not all of the same kind; there are

3-5

four kinds, called adenine, thymine, cytosine, and guanine, but let us call them

A, B, C, and D. The interesting thing is that only certain pairs can sit opposite

each other, for example A with B and C with D. These pairs are put on the two

chains in such a way that they "fit together," and have a strong energy of interaction.

However, C will not fit with A, and B will not fit with C; they will only fit

in pairs, A against B and C against D.Therefore if one is C, the other must be

D, etc. Whatever the letters may be in one chain, each one must have its specific

complementary letter on the other chain.

What then about reproduction? Suppose we split this chain in two. How

can we make another one just like it? If, in the substances of the cells, there is a

manufacturing department which brings up phosphate, sugar, and A, B, C, D

units not connected in a chain, the only ones which will attach to our split chain

will be the correct ones, the complements of BAADC . . .,namely, ABBCD ...

Thus what happens is that the chain splits down the middle during cell division,

one half ultimately to go with one cell, the other half to end up in the other cell;

when separated, a new complementary chain is made by each half-chain.

Next comes the question, precisely how does the order of the A, B, C, D units

determine the arrangement of the amino acids in the protein? This is the central

unsolved problem in biology today. The first clues, or pieces of information,

however, are these: There are in the cell tiny particles called microsomes, and

it is now known that that is the place where proteins are made. But the microsomes

are not in the nucleus, where the DNA and its instructions are. Something

seems to be the matter. However, it is also known that little molecule pieces come

off the DNA-not as long as the big DNA molecule that carries all the information

itself, but like a small section of it. This is called RNA, but that is not essential.

It is a kind of copy of the DNA, a short copy. The RNA, which somehow carries

a message as to what kind of protein to make goes over to the microsome; that

is known. When it gets there, protein is synthesized at the microsome. That is

also known. However, the details of how the amino acids come in and are arranged

in accordance with a code that is on the RNA are, as yet, still unknown. We do

not know how to read it. If we knew, for example, the "lineup" A, B, C, C, A,

we could not tell you what protein is to be made.

Certainly no subject or field is making more progress on so many fronts at

the present moment, than biology, and if we were to name the most powerful

assumption of all, which leads one on and on in an attempt to understand life,

it is that all things are made of atoms, and that everything that living things do can

be understood in terms of the jigglings and wigglings of atoms.

3-4 Astronomy

In this rapid-fire explanation of the whole world, we must now turn to

astronomy. Astronomy is older than physics. In fact, it got physics started by

showing the beautiful simplicity of the motion of the stars and planets, the understanding

of which was the beginning of physics. But the most remarkable discovery

in all of astronomy is that the stars are made of atoms of the same kind as those on

the earth* How was this done? Atoms liberate light which has definite fre-

* How I'm rushing through this! How much each sentence in this brief story contains.

"The stars are made of the same atoms as the earth." I usually pick one small topic like

this to give a lecture on. Poets say science takes away from the beauty of the stars-mere

globs of gas atoms. Nothing is "mere." I too can see the stars on a desert night, and

feel them. But do I see less or more ? The vastness of the heavens stretches my imagination-

stuck on this carousel my little eye can catch one-million-year-old light. A vast

pattern-of which I am a part-perhaps my stuff was belched from some forgotten

star, as one is belching there. Or see them with the greater eye of Palomar, rushing all

apart from some common starting point when they were perhaps all together. What

is the pattern, or the meaning, or the why ? It does not do harm to the mystery to know

a little about it. For far more marvelous is the truth than any artists of the past imagined!

Why do the poets of the present not speak of it ? What men are poets who can speak of

Jupiter if he were like a man, but if he is an immense spinning sphere of methane and

ammonia must be silent?

3-6

quencies, something like the timbre of a musical instrument, which has definite

pitches or frequencies of sound. When we are listening to several different tones

we can tell them apart, but when we look with our eyes at a mixture of colors we

cannot tell the parts from which it was made, because the eye is nowhere near as

discerning as the ear in this connection. However, with a spectroscope we can

analyze the frequencies of the light waves and in this way we can see the very tunes

of the atoms that are in the different stars. As a matter of fact, two of the chemical

elements were discovered on a star before they were discovered on the earth.

Helium was discovered on the sun, whence its name, and technetium was discovered

in certain cool stars. This, of course, permits us to make headway in

understanding the stars, because they are made of the same kinds of atoms which

are on the earth. Now we know a great deal about the atoms, especially concerning

their behavior under conditions of high temperature but not very great

density, so that we can analyze by statistical mechanics the behavior of the stellar

substance. Even though we cannot reproduce the conditions on the earth, using

the basic physical laws we often can tell precisely, or very closely, what will happen.

So it is that physics aids astronomy. Strange as it may seem, we understand the

distribution of matter in the interior of the sun far better than we understand the

interior of the earth. What goes on inside a star is better understood than one might

guess from the difficulty of having to look at a little dot of light through a telescope,

because we can calculate what the atoms in the stars should do in most circumstances.

One of the most impressive discoveries was the origin of the energy of the

stars, that makes them continue to burn. One of the men who discovered this was

out with his girl friend the night after he realized that nuclear reactions must be

going on in the stars in order to make them shine. She said "Look at how pretty

the stars shine!" He said "Yes, and right now I am the only man in the world

who knows why they shine." She merely laughed at him. She was not impressed

with being out with the only man who, at that moment, knew why stars shine.

Well, it is sad to be alone, but that is the way it is in this world.

It is the nuclear "burning" of hydrogen which supplies the energy of the sun;

the hydrogen is converted into helium. Furthermore, ultimately, the manufacture

of various chemical elements proceeds in the centers of the stars, from hydrogen.

The stuff of which we are made, was "cooked" once, in a star, and spit out. How

do we know? Because there is a clue. The proportion of the different isotopes-

how much C12, how much C13, etc., is something which is never changed by

chemical reactions, because the chemical reactions are so much the same for the

two. The proportions are purely the result of nuclearreactions. By looking at the

proportions of the isotopes in the cold, dead ember which we are, we can discover

what the furnace was like in which the stuff of which we are made was formed.

That furnace was like the stars, and so it is very likely that our elements were

"made" in the stars and spit out in the explosions which we call novae and supernovae.

Astronomy is so close to physics that we shall study many astronomical

things as we go along.

3-5 Geology

We turn now to what are called earth sciences, or geology. First, meteorology

and the weather. Of course the instruments of meteorology are physical instruments,

and the development of experimental physics made these instruments

possible, as was explained before. However, the theory of meteorology has never

been satisfactorily worked out by the physicist. "Well," you say, "there is nothing

but air, and we know the equations of the motions of air." Yes we do. "So if

we know the condition of air today, why can't we figure out the condition of the

air tomorrow?" First, we do not really know what the condition is today, because

the air is swirling and twisting everywhere. It turns out to be very sensitive, and

even unstable. If you have ever seen water run smoothly over a dam, and then

turn into a large number of blobs and drops as it falls, you will understand what I

mean by unstable. You know the condition of the water before it goes over the

3-7

spillway; it is perfectly smooth; but the moment it begins to fall, where do the

drops begin? What determines how big the lumps are going to be and where they

will be? That is not known, because the water is unstable. Even a smooth moving

mass of air, in going over a mountain turns into complex whirlpools and eddies.

In many fields we find this situation of turbulent flowthat we cannot analyze today.

Quickly we leave the subject of weather, and discuss geology!

The question basic to geology is, what makes the earth the way it is? The

most obvious processes are in front of your very eyes, the erosion processes of

the rivers, the winds, etc. It is easy enough to understand these, but for every bit

of erosion there is an equal amount of something else going on. Mountains are

no lower today, on the average, than they were in the past. There must be mountsim-

forming processes. You will find, if you study geology, that there are

mountain-forming processes and vulcanism, which nobody understands but which

is half of geology. The phenomenon of volcanoes is really not understood. What

makes an earthquake is, ultimately, not understood. It is understood that if

something is pushing something else, it snaps and will slide-that is all right.

But what pushes, and why? The theory is that there are currents inside the earth-

circulating currents, due to the difference in temperature inside and outside-

which, in their motion, push the surface slightly. Thus if there are two opposite

circulations next to each other, the matter will collect in the region where they

meet and make belts of mountains which are in unhappy stressed conditions, and

so produce volcanoes and earthquakes.

What about the inside of the earth? A great deal is known about the speed of

earthquake waves through the earth and the density of distribution of the earth.

However, physicists have been unable to get a good theory as to how dense a

substance should be at the pressures that would be expected at the center of the

earth. In other words, we cannot figure out the properties of matter very well in

these circumstances. We do much less well with the earth than we do with the

conditions of matter in the stars. The mathematics involved seems a little too

difficult, so far, but perhaps it will not be too long before someone realizes that

it is an important problem, and really work it out. The other aspect, of course, is

that even if we did know the density, we cannot figure out the circulating currents.

Nor can we really work out the properties of rocks at high pressure. We cannot

tell how fast the rocks should "give"; that must all be worked out by experiment.

3-6 Psychology

Next, we consider the science of psychology.Incidentally, psychoanalysis is

not a science: it is at best a medical process, and perhaps even more like witchdoctoring.

It has a theory as to what causes disease-lots of different "spirits,"

etc. The witch doctor has a theory that a disease like malaria is caused by a spirit

which comes into the air; it is not cured by shaking a snake over it, but quinine

does help malaria. So, if you are sick, I would advise that you go to the witch

doctor because he is the man in the tribe who knows the most about the disease;

on the other hand, his knowledge is not science. Psychoanalysis has not been

checked carefully by experiment, and there is no way to find a list of the number

of cases in which it works, the number of cases in which it does not work, etc.

The other branches of psychology, which involve things like the physiology

of sensation-what happens in the eye, and what happens in the brain-are, if

you wish, less interesting. But some small but real progress has been made in

studying them. One of the most interesting technical problems may or may not

be called psychology. The central problem of the mind, if you will, or the nervous

system, is this: when an animal learns something, it can do something different

than it could before, and its brain cell must have changed too, if it is made out of

atoms. In what way is it different ? We do not know where to look, or what to

look for, when something is memorized. We do not know what it means, or what

change there is in the nervous system, when a fact is learned. This is a very important

problem which has not been solved at all. Assuming, however, that there is

some kind of memory thing, the brain is such an enormous mass of interconnect-

3-8

ing wires and nerves that it probably cannot be analyzed in a straightforward

manner. There is an analog of this to computing machines and computing elements,

in that they also have a lot of lines, and they have some kind of element,

analogous, perhaps, to the synapse, or connection of one nerve to another. This

is a very interesting subject which we have not the time to discuss further-the

relationship between thinking and computing machines. It must be appreciated,

of course, that this subject will tell us very little about the real complexities of

ordinary human behavior. All human beings are so different. It will be a long

time before we get there. We must start much further back. If we could even figure

out how a dog works, we would have gone pretty far. Dogs are easier to understand,

but nobody yet knows how dogs work.

3-7 How did it get that way?

In order for physics to be useful to other sciences in a theoretical way, other

than in the invention of instruments, the science in question must supply to the

physicist a description of the object in a physicist's language. They can say "why

does a frog jump?," and the physicist cannot answer. If they tell him what a frog

is, that there are so many molecules, there is a nerve here, etc., that is different.

If they will tell us, more or less, what the earth or the stars are like, then we can

figure it out. In order for physical theory to be of any use, we must know where

the atoms are located. In order to understand the chemistry, we must know

exactly what atoms are present, for otherwise we cannot analyze it. That is but

one limitation, of course.

There is another kind of problem in the sister sciences which does not exist

in physics; we might call it, for lack of a better term, the historical question.

How did it get that way? If we understand all about biology, we will want to

know how all the things which are on the earth got there. There is the theory of

evolution, an important part of biology. In geology, we not only want to know

how the mountains are forming, but how the entire earth was formed in the beginning,

the origin of the solar system, etc. That, of course, leads us to want to

know what kind of matter there was in the world. How did the stars evolve?

What were the initial conditions? That is the problem of astronomical history.

A great deal has been found out about the formation of stars, the formation of

elements from which we were made, and even a little about the origin of the

universe.

There is no historical question being studied in physics at the present time.

We do not have a question, "Here are the laws of physics, how did they get that

way?" We do not imagine, at the moment, that the laws of physics are somehow

changing with time, that they were different in the past than they are at present.

Of course they may be, and the moment we find they are, the historical question

of physics will be wrapped up with the rest of the history of the universe, and then

the physicist will be talking about the same problems as astronomers, geologists,

and biologists.

Finally, there is a physical problem that is common to many fields, that is

very old, and that has not been solved. It is not the problem of finding new fundamental

particles, but something left over from a long time ago-over a hundred

years. Nobody in physics has really been able to analyze it mathematically

satisfactorily in spite of its importance to the sister sciences. It is the analysis of

circulating or turbulent fluids. If we watch the evolution of a star, there comes a

point where we can deduce that it is going to start convection, and thereafter we

can no longer deduce what should happen. A few million years later the star

explodes, but we cannot figure out the reason. We cannot analyze the weather.

We do not know the patterns of motions that there should be inside the earth.

The simplest form of the problem is to take a pipe that is very long and push water

through it at high speed. We ask: to push a given amount of water through that

pipe, how much pressure is needed? No one can analyze it from first principles

and the properties of water. If the water flows very slowly, or if we use a thick

goo like honey, then we can do it nicely. You will find that in your textbook.

3-9

What we really cannot do is deal with actual, wet water running through a pipe.

That is the central problem which we ought to solve some day, and we have not.

A poet once said, "The whole universe is in a glass of wine." We will probably

never know in what sense he meant that, for poets do not write to be understood.

But it is true that if we look at a glass of wine closely enough we see the entire

universe. There are the things of physics: the twisting liquid which evaporates

depending on the wind and weather, the reflections in the glass, and our imagination

adds the atoms. The glass is a distillation of the earth's rocks, and in its

composition we see the secrets of the universe's age, and the evolution of stars.

What strange array of chemicals are in the wine? How did they come to be?

There are the ferments, the enzymes, the substrates, and the products. There in

wine is found the great generalization: all life is fermentation. Nobody can

discover the chemistry of wine without discovering, as did Louis Pasteur, the cause

of much disease. How vivid is the claret, pressing its existence into the consciousness

that watches it! If our small minds, for some convenience, divide this glass

of wine, this universe, into parts-physics, biology, geology, astronomy, psychology,

and so on-remember that nature does not know it! So let us put it all

back together, not forgetting ultimately what it is for. Let it give us one more final

pleasure: drink it and forget it all!

Answer 3

they are directly interelated, Social science is the study of behavior of organisms behavior with eachother. Natural science is the study of all things in nature, therefore social science is a subset of natural science.

Answer 4

Relationship with biology< Ecology being the study about the interaction between living organism and abiotic components and biology being the study of living organisms they hold some basic base line that is they deal with the living organisms.

Its application can be that with the help of biological interpretition we can have the knowledge about the organisms and ultimately their interactions with the abiotic component of the environment

Ecology is also related to chemistry in that our changing environment changes the chemical makeup of the air and water, potentially throwing the Earth's chemistry off balance.

Answer 5

Sociologists study the behavior and relationships in groups, they could be related with anthropology which studies cultures and they are related because both are interested in the relationships,behaviors,cultural,etc of humans.

Answer 6

Anthropology is related to Archaeology because these sciences are used to reconstruct the past based on archaeological records. It is also related to sociology.

Answer 7

Science is related to everything.