Lecture 2-4-scientific methods

Question 1

Science of phrenology

Answer 1

At the end of the eighteenth century at the University of Vienna in central Europe, two lecturers, F. C. Gall and J. C. Spurzheim, developed the “science” of phrenology. The theory was that the brain determined human personality. Different character traits were
formed by different parts of the brain and the relative size of each part would therefore indicate the strength of each characteristic of an
individual. Most importantly, Gall and Spurzheim believed that by studying the external shape of the skull, they could reveal these
characteristics.

Question 2

Reputation of science

Answer 2

It is now fully supported by our educational systems; the sciences are taught in schools and universities around the world.
* The increase in human knowledge that has resulted from science has led to many improvements in our lives. By applying scientific methods and the resulting knowledge, human beings can now control their environment to a far greater extent than was possible before.
* Improvements in medicine and developments in science and technology based industries, have brought scientists respect and considerable financial support from governments and the private sector.
* Some people see science as the “highest” form of human reasoning.
* The scientific approach is now applied to a wide range of disciplines that were previously considered non-science

Question 3

Why is scientific knowledge considered “proven knowledge”?

Answer 3

This reputation rests on the belief that scientific knowledge is objective and reliable because of the methodology of science. Scientific
methods are seen as making use of observation and experiment, to discover natural laws from which theories can be constructed and
predictions made. These methods are considered to be culturally neutral and open to all. Given the right tools and the opportunity,
any individuals conducting a particular investigation properly should reach the same conclusions.

Other cognitive practices are believed to possess considerable weaknesses when compared to science. Science is said to be rational, based
on reason, while other practices are judged to be ideological, based on theoretical ideas and assumptions, not necessarily based on
facts. It is thought that the scientific method allows us to escape from ideology. But does the practice of science actually live up to
these high ideals?

Question 4

The inductivist view of science

Answer 4

According to the inductivist, science starts with observation. The observer should have normal sense organs, should record with an
unprejudiced mind what he or she can see, hear, smell, and touch with respect to the situation. Facts about the world can be determined and established as true by an observer’s use of his or her senses. In the inductivist perspective, these facts constitute the base from which the laws and theories that make up scientific knowledge
are derived

Question 5

Inductive reasoning

Answer 5

means that a general rule is framed on the basis of a collection of individual observations (or “facts”).

Question 6

Inductive method

Answer 6

How do we go from making observations to making statements of scientific knowledge or laws? The inductivist says that we can justify
scientific laws on the basis of a finite number of observations and that if certain conditions are met we can then generalise from observations to a universal law. As an example, let us consider the heating of bars of metals. When bars of metal are heated, it can be shown that they expand, although only by small amounts. Thus we go from observing heated metal bars to the general law, “Metals expand when heated”

Question 7

The inductivist view of scientific progress

Answer 7

According to inductivists, science continues to grow as the quantity of data available to us increases. As the number of facts established
by observation increases, and the facts become more precise (due to improved methods of observing and better equipment), more and more laws and theories of greater scope may be constructed by inductive reasoning. The perception that inductivist science is objective and reliable derives from the fact that both observation and inductive reasoning are themselves believed to be objective

Question 8

Difficulties with induction

Answer 8

From an inductivist point of view scientific laws are generalisations from observations. As we call these generalisations “laws” they sound certain. (The word law seems to imply that nature must obey them!) In fact, scientific laws cannot be firmly established, confirmed or proven in this way. This is because they cannot cover
all the possible situations to which they are applied. Scientists cannot make all the observations that would be necessary so there is always the possibility that an exception will arise.

Question 9

Problem of induction

Answer 9

Induction cannot be justified on logical grounds. (Chalmers 1982). Induction is therefore not a logically valid process. It appears that
scientific knowledge has so-called laws, which are not derived in a logical way

Question 10

How does science progress?

Answer 10

by accumulating facts from making
observations.

Question 11

Difficulties with incision

Answer 11

An exception may turn up despite previously making a large number of observations. There is no way to know how many observations or how many different circumstances are enough, except by referring to a theory. Using
theory contradicts the supposedly objective nature of inductive reasoning.

Question 12

A deduction

Answer 12

is therefore a statement about the properties
or behaviour of a particular object (or situation) that is derived from what
is already known about the group to which the particular object (or situation) belongs.

Question 13

Deductive reasoning

Answer 13

involves inferring particular instances from a
general law i.e. using what is general to predict what is true for a specific case

Question 14

Induction vs deduction

Answer 14

In induction we argue from the particular to the general. After making observations about an object or situation we apply and extend the
resulting statement to new objects or situations. In deduction, on the other hand, we go from the general to the particular; we apply the consequences of a general statement to one particular object or situation that belongs to the class to which the general statement refers.
Deductive arguments are logically valid but inductive arguments are not. Deductive reasoning is therefore safer than induction provided the initial general statement is true. An inductive statement, however, always involves an element of doubt, as it is possible to arrive at a
wrong inference from correct information.

General statements (laws) do not necessarily follow from the particular observations
made and we cannot be sure that laws will always be obeyed. Only inductive reasoning opens new horizons and sets new problems.
Deduction does not, give us anything new. Not only does induction summarise the information we have gathered but it also expands
our knowledge. For example, observations may suggest hypotheses to be tested. Induction, although it has its problems, can play a
useful role in furthering scientific knowledge. Deduction only relates the consequences of the initial statements to the case being considered. It does not suggest further investigation.

Question 15

Deductive reasoning and scientific theory

Answer 15

We can now understand one way that scientific laws and theories may be used to either predict future events from present knowledge or
explain events that have occurred.

Question 16

The Hypothetico-Deductive
Approach

Answer 16

It is based on using observations to formulate hypotheses, testing them under controlled conditions and arriving at conclusions,
based on the findings of the tests. These findings may not support the original hypothesis.

Question 17

This scientific method can be broken down into four steps:

Answer 17

1. Observation: Some event or situation is observed that presents a problem. It may be the results of a previous investigation or some occurrence in nature that a scientist wishes to know more about.
2. Hypothesis formation: An explanation for the event is put forward. This hypothesis suggests a cause for the observation.
3. Prediction: The hypothesis is used to make one or more predictions as to what would happen, if it were true.
4. Experimentation: Finally, the hypothesis is tested to see if the predictions were accurate. These tests are carried out under carefully controlled conditions to ensure that the results are reliable.

Question 18

Define a hypothesis

Answer 18

as a reasoned guess formulated as a statement of expectation about the things being studied

Question 19

The role of hypotheses-explanation

Answer 19

Since the hypothesis suggests a cause scientists can predict that if certain conditions are
met then particular results will follow. A very simple example will make the point. If a hypothesis states that “seeds of species X need
light to germinate” then it can be predict that they will not germinate if kept in the dark. Scientists can then collect many of the seeds, divide them into two batches expose both sets to conditions ideal for germination except that one set will be kept in the dark and the other in the light.

Question 20

The main value of hypotheses

Answer 20

is that they encourage and initiate
experimental activity. If this activity supports the hypothesis we may maintain the hypothesis for further testing. If the initial results
of testing lead to rejection of the hypothesis it points the researcher in another direction

Question 21

Hypothesis and testing: Dependent and independent variables

Answer 21

Common sense tells us that because two things happen at the same time it does not mean that one causes the other. There may be other
factors (variables) involved in this coincidence that are less obvious. (Ignoring this possibility is a very common error in explaining the
causes of everyday events.) Experimentation takes observation further and usually involves
making observations under carefully controlled conditions. A central feature of many experiments is that all but one of the variables that are under the experimenter’s control, are kept constant. By controlling conditions important relations are not obscured by accidental, unimportant or interfering circumstances.

Question 22

Experiments and testing theories
Galileo and the importance of observed “ facts”

Answer 22

Galileo was one of the first scientists to break with the tradition of his day. He felt that established facts or observations should be accepted as such even when the observations did not fit into a currently accepted theory. This may seem obvious to us but in Galileo’s day
scientific observations were frowned on if they did not support accepted versions of the world. For Galileo, the important thing was
to accept the facts and build or modify the theory to fit them.

Question 23

Popper and falsifying theories

Answer 23

More recently the philosopher Karl Popper emphasised the use of experiments that can show theories to be false. He holds that it is
precisely the fact that scientific theories can be falsified by experiment that distinguishes scientific knowledge from other ideologically based disciplines, where whenever contrary evidence is presented it is always explained away. In Popper’s view, science proceeds by the formation of hypotheses and by attempts to disprove the hypotheses by testing them. Progress is made when a hypothesis is tested and a new observation or experimental result shows that something is “wrong” with a theory.
The theory must then be modified or corrected to accommodate the new findings thus improving its accuracy; the result is a better theory. This is very different from the popular view of science, which focuses on gathering evidence to prove a theory.

Question 24

Example of

Answer 24

As an everyday example, consider the boiling point of water. Repeated measurements of the boiling point of water in Bridgetown, Kingston, Roseau, Port of Spain, St. John’s and so on, support the law, “The boiling point of water is 100 degrees Celsius (100oC)”. When the boiling point of water is measured at Knox College in
Jamaica, however, it is always a couple of degrees less than 100 oC.
Can you think of two effects this might have?
1. It disproves the original law (it falsifies the law).
2. It leads to a search for a suitable way to modify the law to include the new information.
The lower boiling point is explained by the fact that Knox College is about 1,000 metres (over 3,000 feet) above sea level. At this altitude
the pressure is lower than at sea level and the boiling point is lower at lower pressures. Thus, the addition of the phrase “at one atmosphere pressure” improves the law, making it more precise. What should the law now state?
Similarly, if instead of pure water we use seawater (which contains many dissolved substances) in the test, at sea level, the boiling point is higher than usual. Thus, a phrase referring to the purity of the water also needs to be added to the law, again improving its precision.

Question 25

The inductive method v e r s u s the hypothetico-deductive approach

Answer 25

Inductivists see experiments and observation as enlarging our store of accepted facts. In the hypothetico-deductive model experiments are designed to test, and potentially deny, our theories and hypotheses. As a way of comparing the two read the following passage and then answer the questions that follow

Question 26

What is a scientific paradigm?

Answer 26

is the set of fundamental beliefs (or premises)to which scientists subscribe and which they use as a framework for conducting research. A scientist that belongs to a certain branch of science is accepting a given set of paradigms. Sometimes when a particular set of beliefs, or ways of looking at some aspect of nature, is accepted for the first time a new paradigm is created and a new discipline or specialisation comes into being.

Question 27

Process of scientific paradigm

Answer 27

Initially new concepts have to be repeatedly defined and defended as the discipline develops its own identity. As more work is done in the area definitions become more detailed and precise. It may reach a point when only scientists working in that area are able to read and understand fully, academic reports of the work. In this way, scientific, and other forms of knowledge, have become sub-divided into more and more specialisations and less available to the general public. Once a paradigm is generally accepted, scientists can take its premises for granted. Work is done to expand knowledge only in the doubtful areas of the paradigm.

Question 28

Scientific revolutions

Answer 28

One inductivist argument claims that science increases knowledge cumulatively. A look at the history of scientific knowledge shows that this is a false description of how science progresses. A new theory often does not add to an old theory but shows instead that it had been false. For example, Copernicus’ (1543) heliocentric theory of the universe (where the Sun is taken as stationary and the Earth orbits around it) did not add to Ptolemy’s (384 BC) theory (where the Sun was believed to orbit the Earth). It showed that Ptolemy was mistaken.

Question 29

Two types of scientific parts

Answer 29

Normal science and extraordinary science

Question 29

Normal and extraordinary science

Answer 29

is research that is based on the currently accepted paradigm. Extraordinary science, on the other hand, takes place outside the paradigm. In the latter case, experiments and observations begin to produce results that contradict parts of the accepted paradigm. As the number of these difficulties grows “extraordinary science” begins. When a body of data starts to accumulate that poses major problems for a theory Kuhn’s process of radical change may occur. A new paradigm takes over, a new consensus begins to prevail and the revolution is underway. The new ideas enable a range of previously puzzling phenomena to be explained and so activities are undertaken to examine these phenomena.

Question 30

Moving continents: rejecting and accepting theories

Answer 30

Scientific revolutions or “paradigm shifts” are usually not instantaneous; years of argument between scientists may precede the final acceptance of the new paradigm. Example: Continents were thought to be unmoving, permanent blocks, surrounded by the oceans, without a history of change. In the eighteenth century, however, it was noticed that the coasts of the continents to the West of the Atlantic (North and South America) and the continents to the East (Africa and Europe) if brought closer, would fit together, somewhat like the pieces of a jigsaw puzzle. Two scientists, the German von Humboldt and the American Snider Pellegrini, suggested that in the past the continents on either side of the Atlantic had been joined together and later separated by floods. A German scientist, Alfred Wegener, then presented a more startling hypothesis; there was once a single original continent that had separated and drifted apart. He offered a wide variety of evidence to support his claim but he was unable to explain how this took place. In the northern hemisphere most scientists scorned Wegener’s idea and did not consider much of the evidence seriously, until the late 1950s. Geophysicists also ridiculed the idea of lateral movements on this large scale on the grounds that the earth’s crust was too rigid. Those who rejected other evidence presented by Wegener, such as the similarity of fossils found on distant continents, had difficulty providing alternative explanations. (By contrast, many geologists in the southern hemisphere had accepted the new paradigm even before the Second World War, as in the South evidence of former links between continents is strong).

Question 31

We have considered a variety of approaches to science and have seen that scientific progress involves changes in the:

Answer 31

(a) findings (the facts) of science; (b) concepts, laws, and theories; (c) methods of reasoning.

Question 32

Thus, an idealised scheme of scientific method could be described by the following:

Answer 32

1. Scientists use systematic observations and quantitative measurements to supplement everyday experience. In most cases instruments are necessary to detect signals that human senses cannot detect or analyse adequately. 2. Predictions based on the theories are tested by experiments designed specifically to check whether a predicted effect exists or not. 3. Scientific investigations are characterised by the careful control of variables while making systematic observations and measurements. 4. Evidence obtained in this way is recorded and analysed. The aims are to discover regularities and patterns and, if possible, to suggest a theory that explains the observations. 5. Sometimes the results of such tests and experiments require rejection of a theory and consequently a paradigm change. More often they provide additional data for refining or modifying the theory.

Question 33

How to verify a scientific theory

Answer 33

educated guesses that work to “explain” observed patterns in the world. Then we test such models for their ability to predict new observations. If such a theory, model or explanation accurately predicts the observations made in a wide variety of tests, it is held to be “verified”

Question 34

o identify two common aspects of any human endeavour that claims to be scientific

Answer 34

1. Its aim is the discovery, description and understanding of facts about the natural world, both living and non-living, whether on a large or small scale. 2. Its methods are based on combinations of observation, experiment, and reasoning

Question 35

Results of observations and experiments

Answer 35

The results of observations and experiments provide a starting point for formulating new hypotheses, models, and theories. New observations and experiments again test these hypotheses, theories, and models. From this process we come to realise that science does not offer certainty. The generalisations are theories that are retained only as long as they are consistent with the known facts of nature or as long as they are useful in making sense of the world. We can assume that someday a number of the present scientific theories, in which we place such great faith, will seem as absurd as “cylindrical objects burn” in our earlier story.