Title Page: The Philosophy and History of ScienceUniversity of the Western CapeBotany Honours: 1999

Guest Lecturer: Dr Karen Joan EslerKje@land.sun.ac.za(021) 808 3063

Contents:1. The Philosophy and History of Science2. Falsification in practice

Theories are generally not rejected simply because they have anomalies nor are they generally accepted simply because they are empirically confirmed. Larry Laudan

For the truth of the conclusions of science, observation is the supreme court of appeal. Sir Arthur Eddington

Science is divided into two categories, physics and stamp-collecting. Lord Rutherford

The early scientistsFrom historical records it appears that Aristotle (384-322 BC) was the first to construct a conceptual framework which we would describe as the science we call Biology. (The word “science” comes from the latin scire, to know, or scio, I know, while “biology” is derived from the Greek, bios, life). Aristotle’s Historia Animalium is a text on general zoology in which he set down all he knew about the animals of the world. Theophrastus (371-287 BC), a contemporary of Aristotle, did for botany what Aristotle did for zoology. However, after these men, and a handful of others, (notably, the philosopher Plato, 428-347 BC), there was little development for many centuries. The Church became the keeper of knowledge and dogma took the place of enquiry. Not that the darkness was complete. Points of light included the likes of Cardinal Nicolas of Cusa, 1401-1464, and Leonardo da Vinci, 1452-1519. The former was sympathetic to science and encouraged the study of mathematics, while the latter eloquently denounced those who preferred to study authorities rather than nature itself.

Figure 1 A time line, showing the years in which selected persons were alive.

Moore (1993) gives the birth year of the Scientific Revolution as 1543, the year Copernicus died. At this time, (European) human beliefs were under the rigid control of the church. Men like Bacon, Hume and Popper developed the philosophy of science. In 1687, Newton published his major contribution to physics, but his theories were to be made more general by Einstein some 250 years later. Einstein’s work was to have considerable influence on a young Karl Popper. Amongst musical composers, Newton could have been Beethoven, or Brahms, both of whom were known to Einstein (he played violin). Jan van Riebeeck was in the Cape from 1652 to 1662, establishing a way station to the East

and the country known as South Africa today. Shaka and Beethoven were contemporaries (but how different their worlds were!) and Jan Smuts (soldier, statesman, philosopher, botanist) lived through the Anglo-Boer wars (1880-1881 and 1899-1902) as well as both World Wars (1914-1918 and 1939-1945).

Moore, in his book, Science as a Way of Knowing, pinpoints 1543 as the birth year of the re-awakening known as the Scientific Revolution, listing three reasons. Firstly, the recovered and translated works of Archimedes (287-212 BC) were published. Secondly, Copernicus (1473-1543) published his theory that the earth revolves around the sun (and not the other way around, as the dogma of the day declared). Thirdly, Vesalius (1514-1564) published his book, based on dissections, on the anatomy of the human body. Vesalius’ account replaced that of Galen who was born around 129 AD and died around200 AD. We are again reminded of relative inactivity that lasted some 17 centuries.

Names like Tycho Brahe (astronomy, 1546-1601), Galileo Galilei (physics and astronomy, 1564-1642), Johannes Kepler (astronomy, 1571-1630), William Harvey (physician, 1578-1657) and René Descartes (philosophy and mathematics, 1596-1650) are found in the record of the Scientific Revolution. To illustrate the contributions made by these people, Descartes, sometimes called the founder of modern philosophy, wrote the famous phrase “cogito ergo sum” – “I think, therefore I am” and we remember him every time we refer to “Cartesian co-ordinates”. However, the name we must emphasize in connection with the philosophy of science is that of Sir Francis Bacon (philosopher, 1561-1626).

The awakening of experimentation – induction and deductionPrior to Bacon, people’s thoughts were guided largely by myth and legends of the day. Superstition and supernatural played important roles. Instead of accepting the word of the authorities of the day, Bacon emphasized that it was better to accumulate knowledge by experiencing the natural world. Up until then, the method was to start an enquiry with a point of view dictated by the Church and then to derive the consequences. For example, the teaching of the Church that man was god’s special creation, all else being put there for the benefit of man, lead to the dogma that the Earth was the centre of the Universe. The observation that the stars and planets moved lead to the conclusion that these rotated about the earth. There are (beautifully crafted) models in museums in Europe which depict this representation of reality. Earth is shown in the middle of the model, with the sun, moon, planets and stars on hoops, encircling the earth. Copernicus published his contrary ideas in 1543, dying shortly after this. Bacon, 50 years later, emphasized the importance of experimentation, the gaining of knowledge about reality by experiencing reality. (It is interesting that the French word “expériences” means “experiment” – to refer to an experience one must use the word “éprouver”. This is probably because the word used by medieval writers, “esperienza” was sometimes used with the meaning “experience”, sometimes “experiment”.

Bacon wanted scientists to begin their studies with data not faith. Collecting data by observation or experiment, the scientist would then be able to formulate an explanation for the workings of the world around them. Today we use the word “induction” to describe a process whereby one argues from the particular (the facts that one has gathered) to the general (the theories one formulates). Bacon was arguing against the form of deductive reasoning that was current in his day. He did not want scientists to begin with statements based on faith (religion) and to deduce the nature of reality from this. Instead he wanted scientist to begin with their experiences in the real world and to build knowledge on these (he wanted scientists to practice induction). This does not mean that deduction, as a method of reaching conclusions, is invalid. Deduction (arguing form the general to the particular) is an important tool used by all modern scientists.

As an example of deduction, a popular misrepresentation of the facts is to be found in cartoons that depict a cave man, a wooden club on his shoulder, dragging a cave woman by the hair while a dinosaur raises its long neck in the background. If (scientists might say to themselves) man evolved from small, furry pre-mammals which scurried around in the undergrowth at the time when the likes of Tyrannosaurus rex lived and died, then we would not expect to find fossils of man in the same rocks containing fossils of dinosaurs. The fact that no rocks have ever been discovered containing fossils of man and dinosaurs is one of the pieces of evidence which allows us (induction) to formulate the hypothesis that man and dinosaurs did not co-exist. Thus, both induction and deduction are thought process used by modern scientists.

All the scientists of his day and for the next three centuries accepted Bacon’s emphasis of induction as a means of learning about the real world. This period is characterized by an explosion in the amount of knowledge gathered by scientists and by the development of the tools that allowed scientists to gather this knowledge. Perhaps the most important of these tools was the microscope, developed to a high degree by Anton von Leeuwenhoek (1632-1723), and used by him to describe micro-organisms. (Recall that Bacon dies in 1626). Robert Hooke (1635-1701), who developed the compound microscope (two lenses, one at either end of the tube, compared to von Leeuwenhoek’s single-lens instrument), studied the finer detail of animals and plants. Hooke was the first to describe cells, but it would be another 200 years before the nature and role of cells would be understood.

Hypothesis, Theory and LawSir Isaac Newton (1642-1727) may have been the first scientist to use the word “hypothesis” as we use it today. (It is difficult to be precise because the word had a somewhat different meaning up until about this time. Therefore, when one finds him being critical about hypotheses, saying that they had no place in scientific investigation, one must first ask what he meant by the word “hypothesis”). Reading between the lines, it seems that he thought of a hypothesis as an explanation for observations made and that such hypotheses would be the basis for experiments that would produce further information. Today, we might define this term in the following way: A hypothesis is a tentative conjecture, proposition or supposition encapsulating the best available knowledge about some phenomenon. Clearly, Newton was thinking in Baconian terms in which knowledge is accumulated by observation (experimentation).

Davis Hume (1711-1776) was a Scottish philosopher who, like Bacon, maintained that knowledge came from observation and experience (rather than from church-supported dogmas). However, contrary to Bacon, Hume was highly critical of induction as a method. Hume’s attack on induction was part of a wider criticism of causal inference (that some event could be inferred to be the cause of another). In regard to induction, Hume pointed out observing that a certain pattern of events lead to a concluding event on a couple of occasions could under no circumstance be taken to justify a belief in a particular pattern would always lead to the concluding event.

Although Hume is considered the first to be critical of induction, it remained the approach taken by scientist for some two centuries following. For example, Darwin (1809-1822) wrote that he used the “true Baconian method”. Ralph W. Lewis, a professor of the department of Natural Sciences at Michigan State University, records (in a paper published in 1988) that in the early 1930’s, when he started to study biology, textbooks and teachers taught the Baconian method as the method of science. This he describes with the words: “gather all the facts, classify them and then somehow, if you have gathered the right facts, they will crystallize into a theory”.

Note Lewis’ use of the word “theory” as a synonym for “hypothesis”. In our opinion, use of this word should be restricted to cases where a hypothesis could no longer be described as being a tentative proposition. We think of a theory as a hypothesis for which there is some considerable degree of acceptance amongst the majority of scientists, without elevating it to the next level, that of “fact”, “truth” or “law”. Atabout the time of Lewis was a student, being taught the Baconian method, Popper was writing a book that would revolutionise scientist’s view of the scientific method.

The modern approach to science: FalsificationAccording to Sir Karl popper (1902-1994), the crucial distinction between science and non-science relates to the presence or absence of falsifiability. If a line of thought has implications that could be used to test the validity of that line of thought, if it could be falsified, then that line of thought could be described as scientific. On the other hand, if a line of thought produced no means of testing the ideas contained, then that line of thoughtcould not be described as scientific. (An obvious example would be to compare astrology to astronomy.) This basic idea, that of falsification, stating that the ability to falsify demarcates science from non-science, was published by Popper in 1934, in the book titled Logik der Forshung. He translated this

book into English (expanding it at the same time) and published it as The Logic of Scientific Discovery in 1959.

Popper began where Hume left off. No matter how many times (he wrote) we see a swan and observed it to be white, we can never logically derive the universal statement “all swans are white”. However, he then went on to point at a logical asymmetry between verification on the on ehand and falsification on the other. He pointed out that one need record only one instance of a black swan to be logically entitled to derive the statement “not all swans are white”. Popper suggested that scientists are never involved in verification (induction); they are always involved in falsification.

Some authors credit Popper with the invention of the “hypothetico-deductive method” but others traced this method back to Newton while others traced it all the way back to Plato. According to this description of how scientists practice their profession, a scientists starts by formulating a hypothesis to describe the workings of some phenomenon. Statements that make predictions about consequences that would allow if the hypothesis were valid are then deduced from the hypothesis. The scientist then exposes him or herself to the conditions of the prediction (for example, an experiment is conducted), and the results are examined to see whether the predicted outcomes occurred. If they did not, then the hypothesis is an adequate description of the phenomenon; falsification has occurred. However, if observations are as predicted then the scientist does not conclude that the hypothesis is true. Instead a properly trained scientist will try to think of some other experiment with which to test the hypothesis.

As we have indicated, we do not agree that Popper invented the hypothetico-deductive method. In our opinion, Popper did no more than write down clearly what was in the minds and practice of the foremost scientists of his day. For example, the first edition of Sir Ronald Fisher’s book Statistical Methods for Research Workers (he was born in 1890 and died in 1962) appeared in 1925. This book sets out many of the basic ideas used today by scientists in the statistical processing of hypotheses. Neyman and Pearson published such a framework in a series of papers appearing between 1928 and 1936. Recall that Popper’s Logik der Forshung was published in 1934.

The first reaction to Popper’s concept of falsification is that the distinction between scientists and non-scientists is that the first are forever trying to falsify their theories. Popper wnet so far as to be prescriptive, suggesting that one should distinguish a scientist from a non-scientist on this basis. An examination of the historical record indicates however that this notion is false. In 1962 Thomas Kuhn (1922-1996) publisked his book The Structure of Scientific Revolutions. In this book he suggested that scientists have, at any one time, a core of information which they do not question (make no attempt to falsify) and that they spend their time working in the periphery around tis core, colouring in the details, as it were. In this phase, Kuhn describes them as practicing normal science and he refers to the basic core as the paradigm. In simplistic terms, scientists practicing normal science are people looking for puzzles to solve. The tools with which these puzzles are solved are supplied by the paradigm, the basic, unquestioned core. The anomalies these scientists might encounter while solving such a puzzle will be noted but the will not necessarily be taken to be critical of the paradigm to such an extent that it should be discarded. However, when enough of these anomalies have accumulated that they can no longer be ignored, a revolution may occur an the paradigm of the day can be replaced by another paradigm, Like all revolutions, this can be a very painful time, with much controversy. However, if the paradigm is accepted an an improvement on the old, then this new paradigm is taken up as the unquestioned core of a new normal science and scientists return to the fleshing out the detail around this core.

Kuhn’s view of science is very attractive because it is such a strikingly accurate description to be found in the historical record of the progress of knowledge. Later in his life, Popper had to concede that his concept of demarcation based on falsifiability was insufficient, that reality is more complicated than this. However, we are of the opinion that Popper’s suggestion that modern scientist should spend their day trying to falsify what they consider to be the truth should not be discarded. According to Kuhn most scientist are practicing normal science most of the time, but, we belive, a healthy dose of self-criticism is always valuable. Popper wanted scientists to formulate their theories unambiguously as possible, so as to expose these theories as far as possible to the possibility of falsification.

We hope that the brief description we’ve given of the history and philosophy of science will help you to walk a middle road between Popper and Kuhn. One day, when you’ve constructed a fine piece of theory, keep in mind that the very best service you could do for your hypothesis (and yourself) would be to think of a strong test which could be used to falsify your hypothesis. The body of knowledge we refer to as science should never be thought as a series of true statements; instead think of science as a collection of statements, none of which has yet been falsified.

ReferencesBlake RM, Ducasse CJ and Madden 1960. Theories of Scientific Method: The Renaissance through the Nineteenth Century. University of Washington Press, Seattle. 346pp.

Brittanica Online. http://www.eb.com/search. (The Encyclopaedia Brittanica on the internet. Search for items such as “induction” and “Hume”).

Dykes N 1996. A Tangled Web of Guesses: A critical Assessment of the Philosophy of Karl Popper. http://www.digiweb.com/igeldard/LA/philosophical/tangled_preface.html.

Fisher RA 1925. Statistical Methods for Research Workers. Oliver and Boyd, Edinburgh. (Subsequent editions appeared in 1928, 1930, 1932, 1934, 1936, 1938, 1941, 1944, 1946, 1950, 1954, 1958, 1970. This book was an immensely important tool for the scientists who lived and worked in the time when it was written.)

Gillespie CC (Ed) 1980. Dictionary of Scientific Biography. Charles Scribner’s Sons, New York. (A rich source of information about the scientists who brought us to where we are today.)

Hacking I (Ed) 1981. Scientific Revolutions. Oxford University Press. 180pp.Hill L 1985. Biology, philosophy. And the scientific method. Journal of Biological Education, 19, 227-231.Kuhn TS 1962. The Structure of Scientific Revolutions. University of Chicago Press. 172pp.Lewis RW 1988. Biology: A Hypothetico-Deductive Science. The American Biology Teacher, 50, 362-366.Magee B 1974. Popper. The Woburn Press, London. 109pp. (A very readable account of the man and his ideas.)Moore JA 1993. Science as a Way of Knowing. Harvard University Press, Cambridge, Massachusetts. 530pp. (A fascinating history of science.)Neyman J and Pearson ES 1928. On the use and interpretation of certain test criteria for the purposes of statistical inferences. Biometrika, 20A, 175 and 263.Neyman J and Pearson ES 1936. Sufficient statistics and uniformly most powerful tests of statistical hypothesis. Statist. Res. Mem., 1, 113.Popper KR 1935. Logik der Forshung. Julius Springer Verlag, Vienna.Popper KR 1959. The Logic of Scientific Discovery. Hutchinson, London. 480pp.Schick T 1997. The End of Science? Skeptical Enquirer. http://www.csicop.org/si/9703/end.htmlShermer M 1992. Sum Ergo Cogito – I Am Therefore I Think: A Skeptical Manifesto. Skeptic, 1, 15-21 or http://www.skeptic.com and follow the pointers to the Skeptic Magazine through to Volume 1, Number 1.Stove D 1982. Popper and after: Four modern irrationalist. Pergamon Press. 116pp. (Discusses Popper, Kuhn and two other important philosophers of this century, Lakatos and Feyerabend.)Tobey RC 1997. Horus Gets In Gear: A Beginner’s Guide to Research in the History of Science. http://www.kaiwon.com/~lucknow/horus/guide/tp1.html.Zalta EN (Ed) 1997. Stanford Encyclopedia of Philosophy. http://plato.stanford.edu

Falsification in practiceAim: To provide some examples of how falsification works in practice

In attempting to explain what scientists do (Chapter 1), we needed to enter in the realms of philosophy and to delve somewhat into the history of science and scientists. One thing that should be clear to you at this stage is that there is no universal conception of science and its methodology. Still, it is possible to identify certain steps that are commonly accepted as components of the scientific method. In this chapter, we will outline the procedure in a slightly more formal way – using both imaginary and real examples.

We have seen how the processes of deductive and inductive logic are both important components of the scientific method. Induction alone is sufficient to allow data collection in an entirely objective manner, but it is often a useful first step, and can certainly lead on to rigorous scientific pursuit.

The inadequacies of the inductive methodJungwirth and Dreyfus (1992) clearly illustrate the inadequacies of the inductive method by asking the following: “If one were asked to consider the following situations and to detect their common features, what should one do?”

A. Students grew plants in the laboratory. One day a gas tap was left open, which was soon discovered. During the following week, purple spots appeared on the leaves of the plants. The students concluded that the escaping gas had caused the spots.

B. One year, the University employed a new hockey coach. Each year, the team plays ten matches in the regional league. Under the previous coach, the University had won almost all the matches, but this year, it lost the first five. At this point, the students went to the sports administrator, and asked that the previous coach be re-hired for the rest of the season.

Apart form the common contextual features of each situation (both cases occurred at education institutions), it is clear that both situations contain certain conclusions about cause-effect relationships. In A, the purple spots were regarded as the effect of the gas leakage, and in B, the teams defeat was attributed to the new coach’s inefficiency. The common denominator of both situations is that they contain invalid conclusions about cause-effect relationships. A logical fallacy was committed. Although the purple spots MIGHT have been attributed to the gas leakage, and the team’s defeats MIGHT have been the new coach’s fault, attributing these changes to the gas and the coach without looking further into the matter, is a blatant case of jumping to conclusions. We have to be sure that the data available to us addresses the questions we have. The problem with the inductive method of science is that it skips this important point.

Figure 2.1. The inductive and hypothetico-deductive methods. The inductive method is unsound on three grounds: logically an unrestricted general statement can never be derived from a limited number of observations; the decision to collect a certain kind of information means that some pre-existing theory must exist; without a theory ‘one might as well go into the gravel pit and count pebbles and describe their colours’ (Darwin). The hypothetico-deductive method is commonly used in science, but falsification presents philosophical difficulties and the complex nature of science often makes decisive falsification impossible; this scheme also fails to recognize the sociological and psychological elements implicit in the practice of science.From: Hill L 1985. Biology, philosophy, and the scientific method. Journal of Biological Education 19: 227.

The hypothetico-deductive methodIt is the aim of science to be OBJECTIVE rather than SUBJECTIVE. The inductive method id problematic because a) one can never derive a “law” from a limited set of observations and b) the decision to collect a certain kind of information means that some pre-existing theory must exist (i.e. it is subjective). Although

the hypothetico-deductive method is commonly used in science, it also represent some philosophical difficulties. However, it is useful to use these ideas to describe the SCIENTIFIC METHOD. Science helps human beings understand the natural world. It is a method based on OBSERVATION, EXPERIMENT and the DEVELOPMENT and TESTING of THEORY. Although the approach is as varied as scientists themselves, there are still certain processes that can be identified as typical of the scientific method.

Scientists are commonly an inquisitive group of people, oftwn having more questions to ask than the answers to provide! On the basis of accumulated scientific DATA (factual information which may have been collected by someone previously – like for example, the purple spots on the protea leaves), scientists generally generate their questions. From these questions, the skill lies in formulating HYPOTHESES. The word sounds rather formal, but a hypothesis can often be no more than an intuitive feeling that the researcher has about the value of some parameter or the existence of some relationship amongst variables. However vague a hypothesis is, its purpose is to give data collection direction.

The hypothetico-deductive method (Figure 1) of proceeding is to recast one’s hypothesis in a version called the “null hypothesis” which is such that one may collect data which will (if the hypothesis in its original form was valid) FALSIFY the null hypothesis. A null hypothesis is generally simply the opposite of the hypothesis one has formulated. (The word “null” is being used here in the sense of “null and void”, not “zero”. The word “null” is intended to indicate that we do not seriously consider the hypothesis concerned to be true!) For example, if we have come to suspect that a certain gas causes purple spots on the leaves of a certain species of plant then our hypothesis might be:

“Butane gas causes localized decay in the leaves of Protea magnifica which manifests in the form of purple spots”.

However, we formulate this in the form of the following null hypothesis (abbreviated to H0):

H0: Butane gas does not cause purple spots on the leaves of Protea magnifica.

The null form of our hypothesis suggests data we might consider collecting. We might consider using the 20 potted specimens of Protea magnifica available to us in two equal groups of size 10. We could enclose each pot in its own large plastic bag for 35 minutes (the time that tap was left on last month) and we could randomly select 10 of these pots. Butane gas could be pumped through the 10 plastic bags while ordinary air is pumped through the plastic bags of the other 10 plants. We could then count the number of purple spots on the leaves of each of the twenty plants in our experiment. If every plant exposed to butane gas (but no other plant) developed purple spots, we would have very strong evidence contradicting the null hypothesis. If none of the 10 treated plants developed purple spots, we would have the weakest possible eveidence against the null hypothesis. Note how we are careful to make statements about the strength of contradictory evidence (the extent of falsification), rather than statements about something “which our experiment has proved”. The point is that our experiment has (in the final analysis) proved nothing. For al we know, it wasn’t just the butane gas, but the combined effect of sunlight and butane gas. (Perhaps we did our experiment at night.) That would explain why we didn’t observe any purple spots in our experiments. Conversely, if we did, perhaps it’s not the presence of butane which is damaging, but the absence of oxygen. Consequently, scientists do not speak of “proof”, but of “strength of the evidence contradicting a null hypothesis”.

On the basis of the evidence collected, it is perfectly natural that in future the scientist will behave in some way consistent with this evidence. Perhaps 7 out of 10 plants exposed to butane gas developed purple spots. Then anybody, not just our scientist, would in future take care not to expose valuable protea plants to butane gas! Using knowledge (even “truths” which are subsequently shown to be false) is a different activity to accumulating knowledge.

Notice that the experiment involved a PREDICTION. IF (our scientist was saying to him or herself) a protea plant is exposed to butane gas, THEN it will develop purple spots. Our scientist had developed a representation of reality in his or her mind that allowed a prediction to be formulated. Such a representation is called a MODEL.

Model formulation is a process by which a scientist combines available knowledge, impressions formed, guesses made and null hypotheses which may need to be tested. A model is not a statement of fact, but something that stands in for reality. Scientists use models because reality is generally much too complicated to be able to make simple unambiguous statements about aspects of that reality. No scientist believes a model. All scientists use models. A model being used today may be shown to be inadequate tomorrow, in which case scientists will use a different model, which works more generally, from the day after tomorrow. In short, a model includes a list of assumptions the scientist is willing to make about the reality being studied.

Scientists are in the business of formulating models, making predictions (statements of consequences that follow on the model), collecting data relevant to these predictions and testing the model with the collected data. If there is some part of the model that the scientists has doubts about, then these doubts will be expressed in the form of an appropriate null hypothesis. Corresponding data will be collected and this will be used to evaluate the strength of evidence contradicting the null hypothesis. On the basis of this evidence, the scientist might reformulate the model, collect new data, and so on and so forth.

The following real-life example should illustrate a cycle in the process of scientific research.

An ExampleLet’s use the example of Myrmecochory in Fynbos.Myrmecochory = seed dispersal by antsFynbos = the small-leaved shrublands found in the western and south-western Cape of South Africa.

Accumulated scientific data: Biologists working with the seeds of Fynbos species observed that seeds of many species (from different families) bear structures called ELIASOMES on the seeds. A survey showed that there were as many as 1300 species with eliasomes (myrmecochorous species) out of a total of 6500 strictly Fynbos species (20%). When surveying for this phenomenon world-wide, biologists found that the only other region to show abundance of these species was Australia (1500 spp out of 18 000, or 8%). Both regions have soils which are nutrient poor and both are subjected to common fires. This scarcity of nutrients suggests that since it is generally costly to produce seeds, there is an advantage to plants which protect those seeds that are produced. On the other hand, the fact that fires can be hot enough to kill seeds that lie on the surface, lead biologists to suspect that these eliasomes might provide a mechanism of seed protection via dispersal. Casual observation indicated that ants were commonly seen in association with these species.

The question:What is the function of the eliasomes in these regions?

The hypothesis: Formulating the hypothesis involves INDUCTIVE REASONING. That is, scientists often use isolated facts to arrive at a possible explanation of the observed phenomenon. In this case, the hypothesis was: Eliasomes on seeds have evolved as an attractant to ant that disperse the seeds to areas below ground thereby protecting the seeds against fire and predation.

To recap: In DEDUCTIVE reasoning, we reason from a hypothesis to a conclusion (if..then). INDUCTIVE reasoning, by contrast, argues backward from a set of observations to a reasonable hypothesis.

Observation and experimentation:Once the hypothesis has been stated, DEDUCTIVE REASONING comes into play, and PREDICTIONS are generated. These often take the form of an “if…then” statement:If ants are responsible for the dispersal of seeds with eliasomes, then we should see ants primarily removing seeds with eliasomes and not those without eliasomes.

In the above example, we have phrased the prediction in terms of the OUTCOME it leads us to expect. This prediction, for example, leads us to expect that ants will remove mostly seeds with eliasomes. We can then test this example by doing a suitable experiment and evaluating the evidence. Formally, however, we do

not test predictions in this form. Rather, we test them in a NULL form that is expressed as a statement AGAINST the prediction. This is know as the NULL hypothesis, and is often expressed in shorthand as H0. The null hypothesis in this example is that ants are not involved in the dispersal of seeds with eliasomes.

To test this null hypothesis, an experiment was formed. Seeds of species with eliasomes (A – E), and seeds of a species without eliasomes (F = CONTROL) were placed near the nest of a common indigenous ant species (Anoplolepis custodiens / Pugnacious ant). The behaviour of the ants in relation to the seeds was observed, and the number of seeds remaining for each species was recorded at five-minute intervals. A typical completed record chart is shown in Figure 2 (from: Slingsby and Bond 1981). Note that NUMERICAL DATA (Figure 2) allows us to investigate some situation OBJECTIVELY, with a minimum of influence from the scientist’s SUBJECTIVE feelings. We use STATISTICS as a tool for evaluating the strength of the evidence (contradicting the null hypothesis) observed in an experiment, but we will deal with this aspect in more detail in later lectures.

Conclusion: In this instance, the data offers strong evidence against the null hypothesis, that ants are not involved in the dispersal of seeds with eliasomes. In other words, the scientist is justified in using the knowledge accumulated in this experiment to behave in future as though ants and eliasomes are part of the seed-dispersal method of the species concerned. However, we can not say that the hypothesis is proven, because there are a whole variety of other possible reasons for the observations recorded. To give an example, perhaps the seeds of Leucadendron xanthoconus (species F) give off a chemical which ants perceive as particularly unpleasant (explaining why none of these seeds were taken) and perhaps eliasomes play no role in the life cycle of the other five plant species. Alternatively, perhaps these five plant species have evolved eliasomes in relation to an activity of a bird species and perhaps none of these seeds taken by the ants ever germinate (all are consumed by the ants).

TIME A B C D E F5:00 20 20 20 20 20 205:05 18 17 17 20 19 205:10 12 11 16 16 19 205:15 7 8 13 16 19 205:20 4 1 10 9 17 205:25 0 0 6 4 16 205:30 0 0 0 2 10 205:35 0 0 0 0 9 205:40 0 0 0 0 6 205:45 0 0 0 0 1 205:50 0 0 0 0 0 20

Figure 2. A record card indicating the preference of an ant species for certain seeds.

NEAREST NEST: 2.5 m FIRST ANT/SEED CONTACT: 20 secSEEDS (20 per species)A = Leucospermum prostratum (Proteaceae); B = Serruria rubricanlis (Proteaceae);C = Sickmannia radiate (Cyperaceae); D = Diosma oppositifolia (Rutaceae);E = Hypodiscus aristatus (Restionaceae); F = Leucadendron xanthoconus (Proteaceae)

None of this speculation detracts from the fact that Slingsby and Bond (the researchers concerned) found strong evidence against their null hypothesis. Instead, they are asking themselves questions like those we have mentioned (Do all species of ants disperse seeds? How well protected are the seeds in ant nests?, as their research continues.(Note: for another example see page 15 of Mader SS 1995. Biology. WC Brown Publishers).

Where do scientific questions come from?

Questions do not spring out of a vacuum. They are usually triggered by something and they may arise from a number of sources. Like: curiosity, casual observation, exploratory observations and previous studies.

One of the richest sources of questions is of course past and ongoing research. This is one of the main reasons why a university is not only a teaching institution, but also a research institution. In order to train YOU, as scientists, we need, as teachers, to be active in our relative fields of research. If there is any message to be gained from this book is that science is DYNAMIC. You can be certain of one thing; we will never be able to understand the natural world entirely. There is always room for new ideas. Finally, we can say that our understanding of the universe to date is based entirely on theories (models) that have not yet been falsified. Some of these theories will stand up to the tests of time, but others will be falsified as scientists look at things from a new perspective.

Will any of you be prepared to accept this challenge?!

Prescribed and recommended readingPrescribed reading:

For information on scientific methodology:Barnard C, Gilbert F and McGregor P 1993. Asking Questions in Biology. Longman Group Limited, Harlow. 1-11; 33; 34-37.

Recommended reading:Cowling R 1992. The Ecology of Fynbos. Oxford University Press, Cape Town. Pages: 187-189. (For information on myrmecochory).

Jungwirth E and Dreyfus A 1992. After this, therefore because of this: one way of jumping to conclusions. Journal of Biological Education 26: 139-142. (For information on the logical problems of the inductive method).

Slingsby P & Bond W 1981. Ants – friends of the Fynbos. Veld and Flora 67: 39-45. (For information on myrmecochory).

How to make a NISL Powerpoint PresentationThe aim of this sectionAn introduction to the most basic of PowerPoint tasks, which enable you to make a PowerPoint presentation.

Note:1. This is not intended to be a comprehensive PowerPoint tutorial. Also a general awareness and understanding of the Windows operating system (98, NT, 2000, XP) is assumed. 2. The tutorial text will be displayed on the left-hand side and accompanying graphics and description on the right-hand side wherever possible.3. The sequence for this tutorial will follow a logical path, that is, how a novice would create a PowerPoint presentation, as opposed to a tutorial which aims to cover all the functions available in PowerPoint.

Start of Instructions

Open up PowerPoint by:A. Clicking on the PowerPoint icon on your desktop ORB. Clicking on the Start button and then on the PowerPoint menu PowerPoint desktop icon

item. Start button

PowerPoint menu item

Views in PowerPointPowerPoint will open up, showing the Outline View on the left-hand side, the Notes Area at the bottom, and the Slide View which normally takes up the largest part of the screen.

Additional Objects

Sometimes PowerPoint will have additional objects displayed, depending on its setup on a particular computer, for example, the Office Assistant

or the Task Pane (graphic on the right-hand side) might be visible.

Also PowerPoint might respond differently depending on the version of PowerPoint you are using. This tutorial was developed using PowerPoint 2002 (Office XP). However, this should not be a major concern as only the most basic of PowerPoint tasks and function will be explored here.

The aim was just to familiarise you with the three basic work areas when opening up PowerPoint, that is the Outline View, the Notes Area, and the Slide View (point 2).

PowerPoint Task Pane

Structure of PowerPoint PresentationBefore you start with your PowerPoint presentation, you need to think about the structure of your presentation. The structure of your presentation could look as follows:Slide 1. Project Title (TITLE)Slide 2. Introduction (CONTENT)Slide 3. Methodology (TITLE)Slide 4. Methodology (CONTENT)Slide 5. Methodology (CONTENT)Slide 6. Methodology (CONTENT)Slide 7. Results (TITLE)Slide 8. Results (CONTENT)Slide 9. Results (CONTENT)Slide 10. Conclusions (TITLE)Slide 11. Conclusions (CONTENT)

You will notice that the presentation in the above example uses title and content slides. PowerPoint allows you to create templates or masters for your title and content slides. These masters (templates) control the overall look (in terms of graphics and text) of your slides. The masters may also significantly reduce the size of your final PowerPoint file by preventing duplication of graphics, which are common to all or some of your slides.Note: The benefits of using master slides will become more apparent as we move through this exercise.

Open NISL_Template_EI_2.pptThe NISL slides need to have the same look in terms of graphics and text. The specific requirements for the slides have been listed in a template file called “NISL_Template_EI_2.ppt”. Open this file by clicking on the menubar File|Open and selecting the file in its containing folder.

Open NISL_Template_EI_2.pptThis template does not use master slides. You can check this by clicking on the menubar, View|Master|Slide Master (see below).

The Slide Master is blank.The four slides you are looking at have a similar look. Slide 1 is a title slide, whereas slides 2-4 are content slides. The graphics have been duplicated (quadrupled?) on all the slides. To eliminate this duplication, we have to set up master slides, that is, (1) title masters and (2) content masters.

Click on Close Master View on the Slide Master View to return to Normal View (see below), alternatively, click on the menubar View|Normal.

Display the GridWhen in Normal View, make the grid visible by clicking on the menubar, View|Grid and Guides and set the grid size to 0.083 inches (the default setting), as shown below.

Click OK.

The Grid as a Visual Aid

The grid is not really necessary, but it provides you with a sense of perspective; allowing you to position elements, such as graphics, where you want them to be. The Snap objects to grid feature allows you to easy position elements in the Slide View area.

Making Master SlidesWe can now start making the master slides (title and content slides) for the template file “NISL_Template_EI_2.ppt”.The common elements on slide 1 which can be used for all your content slides are:1. Green circle 1 = Main background image2. Green circle 2 = Content background image3. Blue rectangle 1 = Main heading (Research Methodology)4. Blue rectangle 2 = Subheading (How to Create…)5. Blue rectangle 3 = Side text (E=I2)6. Image 1 = Africa7. Image 2 = FruitflyImportant note: Element 4 (the text box), “How to Create a NISL PowerPoint” must NOT be copied onto the Master Slide if this subheading changes from slide to slide. So this text box will need to be copied from slide to slide.

Selecting the common elementsSelect all six (6) elements listed above by holding down the shift key and clicking on each element. Notice Element 4 has not been selected.

Normal ViewClick on Close Master View on the Slide Master View to return to Normal View (see below), alternatively, click on the menubar View|Normal.

Normal View 2Content slide 1 will display all six (6) elements from the master content slide. These elements can only be selected and edited in the Slide Master View. Content slide 1 will also display element 4. However, unlike the six (6) elements, element 4 can be selected and edited in Normal View.

Insert a New Slide?Insert a new slide (menubar Insert|New Slide or Ctrl-M).

Insert a New Slide?2The newly inserted slide will have all the elements of the master content slide, as well as two extra text boxes.

Copy and Paste a New Slide InsteadThis is not always the best way to insert new slides. Instead of inserting a new slide, it is better to select slide 1 on the Outline View (left panel) and then to copy and paste it. So undo (Ctrl-Z) the insertion of the new slide, select slide 1, copy (Ctrl-C or Edit|Copy or ) it, and immediately paste (Ctrl-C or Edit|Paste or ) it.

The resultant second slide can now easily be edited. If you need more slides, just copy any of the preceding slides to add a new slide.

Creating a Title Master1You should be able to create a content slide master at this stage. The next step is to create the second master slide, namely, the title master. Go to the Slide Master View by clicking on the menubar, View|Master|Slide Master (see below).

Creating a Title Master2In the Slide Master View, click on the Insert New Title Master.

A new slide gets appended to the Slide Master. If you move the mouse cursor over the two slides, you will see the following:

Editing your Title MasterYou can now edit your title master slide, by removing elements which make it look like a content slide.You could end up with a Title Master that looks as follows:

Click on Close Master View on the Slide Master View to return to Normal View (see below), alternatively, click on the menubar View|Normal.

Inserting your Title Slide

In Normal View, select slide number 1. Insert a new slide (menubar Insert|New Slide or Ctrl-M).

Set Slide as Master Slide1Drag the newly created slide, from slide position 2 to the top position (slide 1 position) in the Outline View.

►

Set Slide as Master Slide2With the slide still selected, go to the Slide Layout Pane (the right hand panel), and select Text Layouts: Title Slide (as shown on the graphic).

Set Slide as Master Slide3

Once you have clicked Text Layouts: Title Slide, as shown above your first slide will change as follows:

Inserting new Content Slides or Master SlidesIf you are working with a content slides and need to insert another content slide, simply copy the one you busy with in the Outline View and then edit the newly recreated slide to continue your sequence of slides.However if you want to add a new title slide, you will do exactly the same as above, but you will have to change the layout of the slide from a content slide to a title slide. You do this by simply clicking on the Text Layouts: Title Slide on the Slide Layout Pane (the right hand panel).

Formatting for the NISL Content Slides 1Before I start with the specific formatting for NISL slides in terms of text (size, colour, etc) and custom animations, you should removed duplication of graphics on slides 4-6.

You will see the duplication (in Normal View) when you select and delete the larger white background on any of the slides 4-6. Even though the white background was selected and deleted, it does not disappear. Although, the background image on the content slide was deleted; the background image on the master stays in place. This goes for the other elements (fly, Africa, title text, etc) as well, and these can be deleted from slides 4-6.

Remember: As a rule, always delete the larger background image when doing this as it will obscure the smaller elements on the slide, which you also need to delete (in Normal View).

Slides 4-6 in your presentation have instructions that determine how NISL slides should look. Next, I will show you how to create these slide.

Select Slide 6 and Insert a new slide (menubar Insert|New Slide or Ctrl-M).

Formatting for the NISL Content Slides 2

The new slide (Slide 7) is empty except for the elements which is on the Content Master Slide. The presentation header, “Research Methodology” can only be edited when you go to view the Master Slide by clicking on the menubar View|Master|Slide Master.

Formatting for the NISL Content Slides 3The presentation header is a special kind of text called WordArt. When you right-click on the header, “Research Methodology”, select Format WordArt to edit it.

The settings for the presentation header is as follows:

Colors and LinesText Font Arial Black

Text SizeFont StyleFont Fill ColourFont Line ColourFont Line DashedFont Line Weight

32Italics White (R:255, G:255, B:255)Grey (R:150, G:150, B:150)Solid0.75 pt

SizeHeightWidth Rotation

0.56”6.8”0°

PositionHorizontalVertical

1.46” From Top Left Corner0.44” From Top Left Corner

Note: You can insert your own WordArt by clicking on the Insert WordArt icon on the Drawing toolbar.

Formatting for the NISL Content Slides 4The settings for the side header (EI-2) is as follows:

Colors and LinesText FontText SizeFont StyleFont Fill ColourFont Line ColourFont Line DashedFont Line Weight

Arial Black36Italics White (R:255, G:255, B:255)Grey (R:221, G:221, B:221)Solid0.75 pt

SizeHeightWidth Rotation

0.24”0.79”90°

PositionHorizontalVertical

9.29” From Top Left Corner1.19” From Top Left Corner

Click on Close Master View on the Slide Master View to return to Normal View (see below), alternatively, click on the menubar View|Normal.

Formatting for the NISL Content Slides 5In Normal View: Add a slide header to your slide. Click on the Text Box icon on the Drawing Toolbar, or alternatively click on the menubar Insert|Text Box. Drag the text box onto your slide and enter your text. Note: Do not worry about the text box size, it will expand as you type text into it.

The settings for the slide header is as follows:

Colors and LinesText FontText SizeFont StyleFont ColourFont Effects

Arial24 up to 39BoldMaroon (R:153, G:0, B:0)Shadow

These settings can be added to the text box, by selecting the text (see below) and then clicking on the menubar Format|Font.

Formatting for the NISL Content Slides 6

Position the cursor over the text, and then right click to Format Text Box.

Formatting for the NISL Content Slides 7You can now change the Position and Size of your Text Box (or Placeholder) using the following settings:

SizeHeightWidth

0.76”7.78”

Rotation 0°

PositionHorizontalVertical

1.37” From Top Left Corner1.23” From Top Left Corner

These changes will give you the following result:

Formatting for the NISL Content Slides 8The next step is to insert a second text. Similarly as with the first text box, Click on the Text Box icon on the Drawing Toolbar, or alternatively click on the menubar Insert|Text Box. Drag the text box onto your slide and enter your text.

Formatting for the NISL Content Slides 8The specifications for the text of the second text box are as follows:

Colors and LinesText FontText SizeFont StyleFont ColourFont Effects

Arial or VerdanaAt least 16 ptRegularDark Green (R:70, G:70, B:0)None

When applied your slide should look more or less as follows:

I will now convert the three points in the slide to bullets. Select the text in the text box, and click on the menubar Format|Bullets and Numbering. Select the square buttons and change their colour to a greenish colour R:128, G:128, B:0 (see below).

Click OK. The result should be that your text is dark green and the buttons are grey.

Note: If you get hanging indents when clicking on the Bullets icon

then you need to click set the bullets to numbers and then change them back to bullets .

Right-click on the text box to change it size and position. The specifications for the text box are as follows:

SizeHeightWidth Rotation

4.46”8.15”0°

PositionHorizontalVertical

1.02” From Top Left Corner2.27” From Top Left Corner

Your slide should look like the image above, that is, have greenish bullets (128:128:0), dark green (70:70:0) text, and the text box is within the display area (preventing text from being clipped when the Slide Show is running).

Formatting for the NISL Content Slides 9You need to add animation to the points in the text. Select the text in the text box (see below).

Click on the menubar Slide Show|Custom Animation (see below).

The right-hand side Task Pane will change or appear as the Custom Animation Task Pane (see below).

Select Add Effect from the Custom Animation Task Pane.

The Custom Animation for text is blinds. Click on Add Effect, then on Entrance and then on 1. Blinds, as shown below:

.

After you have clicked on 1. Blinds, your Slide View and Custom Animation Task Pane will look as follows:

You will need to make the following changes to the above settings:

Change the speed of the animation from Very Fast to Fast. The setting can be change on the Custom Animation Task Pane, Modify Blinds: Speed: Fast. Do this for all three (3) points.

Then, double-click Point 1 on the Custom Animation Task Pane (see below).

Change the settings from this (see below):

To this (see below):

Now do the same for Point 2 and Point 3.

You have now set the animation effect for Points 1-3. Next you will need to change the animation sequence for Points 1-3. You do this by right-clicking Point 2 in the Custom Animation Task Pane, and then changing it form Start With Previous to Start On Click.

Repeat this for Point 3. When you have done this you will notice that the grey numbers next to the points have changed from 1-1-1 to 1-2-3 (see below).

Select Slide Show (from current slide) on the bottom left of your screen, to view the animation.

Formatting for the NISL Content Slides 10That concludes inserting headers, text boxes, and custom animation. I will show you how to do some additional text formats that you must use on your NISL slides.

Shadow Text

Select the text from Point 1 (see below).

Click on the menubar Format|Font.

Change Point 1’s text to Shadow text.

Click OK. Select Slide Show (from current slide) on the bottom left of your screen, to get a better view of the shadow text.

You should know by now how to change font colours. Click on the menubar Format|Font.

If you want to use other colours on your slides, you can use the following:

Colour RGB (red, green, blue)Secondary 100 : 100 : 0

Tertiary 128 : 128 : 0Emphasis 204 : 153 : 0

You can also refer to slide 7 to see the effect of the above colours on the slide.

Hyperlink colours

Hyperlink colours are different to Primary, Secondary and the other colours that you can apply to your slides. The reason for this is that hyperlink colours (unvisited link and visited link) are set to a default colour (usually corresponding to your web browser’s setting for these colours). You can change the hyperlink colours as follows:

Click on the menubar Format|Slide Design.

The Slide Design Task Pane will appear on the right-hand side of your screen.

Click on Color Schemes on the Slide Design Task Pane.

Click on Edit Color Schemes, at the bottom of the Slide Design Task Pane.

The Edit Color Scheme dialog (above) allows you to change a number of colours for your slides. However, only the last two in the list is of interest to us, namely, Accent and hyperlink and Accent and followed hyperlink.

Double-click the Accent and hyperlink colour as shown above. The following dialog will appear which will allow you to change the Accent and hyperlink colour.

The colour settings for hyperlinks on NISL slides are:

Colour RGB (red, green, blue)Accent and hyperlink 96 : 132 : 113Accent and followed hyperlink 204 : 102 : 0

After you have inserted the above settings for the two types of hyperlinks, insert a hyperlink onto your slide.

Change the text of Point 2 and 3 as follows:

Select the text as follows:

Click on the menubar Insert|Hyperlink.

Or click the Insert Hyperlink icon on the Standard toolbar (see below).

Insert http://www.google.co.za. (Do not click on this link!)

Do the same for the text for Point 3 (was been changed to “Google (visited link).

Both points now have hyperlinks.

Select Slide Show (from current slide) on the bottom left of your screen, to view the animation.

Both links are still unvisited, so both shows the unvisited hyperlink colour. While still in Slide Show mode, click now on the link, “Google (visited link)”. You will be taken to Google in your web browser.

Return to the slide show and the link will show the orange visited hyperlink colour (see below).

Formatting for the NISL Content Slides 11Before concluding this section, “How to make a NISL Powerpoint Presentation”, there is just two more things which need to be done, that is insertion of extra text boxes and images.

Additional text boxes can be inserted onto your NISL slide as long as it does not obscure other elements (text or images) on your slide. These textboxes also need to have rounded corners to show that they have been added to the slide (see below).

Insert a rounded text box, by clicking on the AutoShapes icon on the Drawing Toolbar. Go to Basic Shapes and click on the Rounded Rectangle (see below).

Once selected, you can drag the rounded rectangle onto your slide (you can position it later not to obscure other elements on your slide).

Type your text into the rounded rectangle. Make it bigger so that your text fits, by dragging the anchors of the rounded triangle out. Then drag it into the position you want it to take on your slide.

Next, right-click on the rounded triangle to format it (see below, Format AutoShape).

Change the Fill Color to No Fill, and click OK (see below).

Select the text in the rounded rectangle and change the font colour to R:70, G:70, G:0.

Next, you need to add a custom animation to the rounded rectangle, which will allow it to appear in sequence with the other elements on your slide.

Select the rounded rectangle, and then click on the menubar Slide Show|Custom Animation (see below).

The right-hand side Task Pane will change or appear as the Custom Animation Task Pane (see below).

Select Add Effect from the Custom Animation Task Pane.The Custom Animation for text is blinds. Click on Add Effect, then on Entrance and then on More Effects, as shown below:

.

After you have clicked on More Effects, another window will appear.

Select Dissolve In from the above window. Your slide should look as follows:

Select Slide Show (from current slide) on the bottom left of your screen, to view the animation.

That concludes inserting additional textboxes to your NISL slide. The insertion of an image is very similar to that of the rounded rectangle. Both have Dissolve In as a custom animation effect, so I will not be repeating this effect. I will instead just show the effect when it is finished.

That concludes this section, “How to make a NISL Powerpoint Presentation”.