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서강대학교 교수학습센터부소장 정유성

Chapt. 2 : What is scientific Method ?

September 14, 2015

* Questions of ‘Fact’ and ‘Value’

• The ‘is’ and the ‘ought’ - Means and Ends

1. fact and value

the descriptive vs the normative• a study of what exists or happens -> Questions of fact• a study of what ought to exist or happen -> Questions of value

 

-> Some questions call for descriptive statements and call for normative statements

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(1) Descriptive statements

: being factual

: assert alleged truth about reality

: deal with what is

not with what ought to be

: identify relationships, e. g. the efficacy or the consequences of the employment of given methods or means

: may indicate what people do or believe or desire

(2) Normative statements

: express conceptions of the desirable

: indicate value preferences

: concern not what is but what ought to be, endorsing ends, purposes or norms

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# What are the grounds of knowledge?

•To answer the question

1) positivism

2) rationalism

 •common–sense positivism

calls met only for a distinction between facts and value,

but also for a distinction between the definitional or logical/ and the empirical

(1) definitional and logical statements (sometimes called analytic)•designed simply to assign meanings, to words, and to clarify the meaning and logical implications of language

=> the principal points:•they should be recognized as such

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• the definition of a word (e.g. justice) should not be construed as the description of either a physical or a metaphysical reality

• For example:

“What is justice?”

-> this question ought to be reformulated in any of several possible ways

e.g. “what meaning is it useful to assign to the word justice?”

: The revised phrasing is preferable

because it is less likely to suggest that justice has a form or essence which men have the opportunity to discover and describe

• and

it is more likely to suggest that justice is what men define it to be.

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(2) empirical statements

•designed to indicate what happens in the world

 

=> the principal points:•they be either verified or verifiable through observation - through the use of one or another of the senses•they are supposed to be descriptive of reality

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2. Ends and means•ought (or should) statements

– sometimes ambiguous

For example: “The study of politics ought to be scientific?”

- Does this sentence express a postulated, self-justifying value – a good-value?

or

- does it come closer to being a factual assertion that the study of politics to be (should be, must be) scientific if some more remote value is to be served most effectively?

Obviously, the problem concerns ends and means •All (or nearly all) ends can alternatively be means, and all means can alternatively be ends.•It depends on where one chooses to break into the means-end chain.

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Therefore,

the problem of clarifying ends and means suggests that the two categories, normative and descriptive, are not entirely adequate•and

a third category is needed • prescriptive:

on the basis of an assumption concerning the end(s) or valued(s) to be promoted,

they prescribe a method or course of action that ought to be pursued.

-> Prescriptive statements thru reflect

a combination of a normative postulate with a descriptive finding.

-> They seem to be most common when the normative postulate its thought to be no generally and thoroughly accepted that it can signify be taken for granted

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1. Theory (1)

• the Greek ‘theorein’ = ‘to look at’

- a number of distinct meanings in different fields of knowledge, depending on their

methodologies and the context of discussion.

- a logically self-consistent model or framework for describing the behavior of a related

set of natural or social phenomena.

- originates from and/or is supported by experimental evidence.

- In this sense, a theory is a systematic and formalized expression of all previous

observations that is predictive, logical and testable.

- In principle, scientific theories are always tentative, and subject to corrections or

inclusion in a yet wider theory.

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• Theories as "models"

Humans construct theories in order to explain, predict and master phenomena (e.g.

inanimate things, events, or the behaviour of animals). In many instances we are

constructing models of reality. A theory makes generalizations about observations and

consists of an interrelated, coherent set of ideas and models.

1. Theory (2)

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* Stephen Hawking in A Brief History of Time

"a theory is a good theory if it satisfies two requirements:

(1) It must accurately describe a large class of observations on the basis of a model that

contains only a few arbitrary elements,

(2) and it must make definite predictions about the results of future observations."

"any physical theory is always provisional, in the sense that it is only a hypothesis; you

can never prove it. No matter how many times the results of experiments agree with some

theory, you can never be sure that the next time the result will not contradict the theory.

On the other hand, you can disprove a theory by finding even a single repeatable

observation that disagrees with the predictions of the theory."

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* Isaac Asimov, In Understanding Physics (1)

"theories as "arguments" where one deduces a "scheme" or model.

Arguments or theories always begin with some premises - "arbitrary elements" as

Hawking calls them, which are here described as "assumptions".

An assumption is "something accepted without proof, and it is incorrect to speak of an

assumption as either true or false, since there is no way of proving it to be either. (If there

were, it would no longer be an assumption.) It is better to consider assumptions as either

useful or useless, depending on whether deductions made from them corresponded to

reality. On the other hand, it seems obvious that assumptions are the weak points in any

argument, as they have to be accepted on faith in a philosophy of science that prides itself

on its rationalism. Since we must start somewhere, we must have assumptions, but at

least let us have as few assumptions as possible."

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not necessarily based on facts -> not required to be consistent with true descriptions of reality

In science,

a theory is a proposed description, explanation,

or model of the manner of interaction of a set of natural phenomena, capable of predicting future occurrences or observations of the same kind, and capable of being tested through experiment or otherwise falsified through empirical observation.

It follows from this that for scientists "theory" and "fact" do not necessarily stand in opposition.

For example, it is a fact that an apple dropped on earth has been observed to fall towards the center of the planet, and the theory which explains why the apple behaves so is the current theory of gravitation.

* Isaac Asimov, In Understanding Physics (2)

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2. Concept (1)

an abstract idea or a mental symbol,

typically associated with a corresponding representation in language or symbology,

abstract in that they omit the differences of the things in their extension, treating them as if they were identical.

universal in that they apply equally to every thing in their extension.

also the basic elements of propositions, much the same way a word is the basic semantic element of a sentence.

Unlike perceptions, which are particular images of individual objects, concepts cannot be visualized.

Because they are not, themselves, individual perceptions, concepts are discursive and result from reason. They can only be thought and designated by a name.

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bearers of meaning, as opposed to agents of meaning.

A single concept can be expressed by any number of languages.

For example,

concept 'DOG' = dog in English, Hund in German, chien in French, perro in Spanish.

The acquisition of concepts is studied in machine learning as supervised classification and unsupervised classification, and in psychology and cognitive science as concept learning and category formation.

A term labels or designates concepts. Several partly or fully distinct concepts may share the same term. These different concepts are easily confused by mistakenly being used interchangeably, which is a fallacy. Ironically, this often arises because the concepts of term and concept are confused, from lacking knowledge that the two are distinct phenomena.

2. Concept (2)

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3. Definition (1)

a form of words which states the meaning of a term.

a descriptive definition - either the meaning which it bears in general use ,

a stipulative definition - the speaker intends to impose upon it for the purpose of his or her discourse

the term to be defined = the definiendum (Latin: that which is to be defined).

the form of words which defines it = the definiens (Latin: that which is doing the defining).

Definition by genus and differentia

a definition consists of the genus of thing to which the defined thing belongs, and the differentia

the genus = the family

the differentia = the distinguishing feature which marks it off from other members of the same family

For example: 'triangle' is defined as 'a plane figure (genus) bounded by three straight sides (differentia).

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How to define ?

1. A definition must set out the essential attributes of the thing defined.

2. The definition must not be too wide or too narrow. It must be applicable to everything to which the defined term applies (i.e. not miss anything out), and to no other objects (i.e. not include any things to which the defined term would not truly apply).

3. A definition should not be negative where it can be positive. We should not define 'wisdom' as the absence of folly, or a healthy thing as whatever is not sick. Sometimes this is unavoidable, however. We cannot define a point except as 'something with no parts', nor blindness except as 'the absence of sight in a creature that is normally sighted'.

3. Definition (2)

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Stipulative definition and Genetic definition

(1) Stipulative definitions differ from descriptive definitions in that they prescribe a new meaning either to a term already in use or to a new term. A descriptive definition can be shown to be right or wrong by comparison to usage, while a stipulative definition cannot.

A stipulative definition, however, may be more or less useful.

A persuasive definition is a form of stipulative definition which purports to describe the 'true' or 'commonly accepted' meaning of a term, while in reality stipulating an altered use, perhaps as an argument for some view, for example that some system of government is democratic.

(2) A genetic definition describes the process or method by which a thing is formed.

"But if you define the circle as a pattern resulting from having a segment of a line revolve around one of its ends, this is a genetic definition because it tells you how to make a circle."

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4. SentenceLatin sententia : perception, in the subjective sense of how one feels reality is

several meanings:

(1) linguistics - a unit of language, characterized in most languages by the presence of a finite verb. For example, "The quick brown fox jumps over a lazy dog."

(2) mathematical logic - a formula with no free variables; it follows that, considering model theory, a sentence is either true or false in a given structure.

(3) law - the final act of a judge-ruled process, and also the symbolic principal act connected to his function. The sentence generally involves a decree of imprisonment, a fine and/or other punishments against a defendant convicted of a crime.

(4) music - "the smallest period in a musical composition that can give in any sense the impression of a complete statement."

It "may be defined as a period containing two or more phrases, and most frequently ending with some form of perfect cadence."

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5. Description

an enumeration of the quantitative and qualitative parameters which seek to provide a definition of some thing, such as what that thing looks like, sounds like, or feels like.

A complete description allows for not merely defining but distinguishing one state from another and general characteristics commonly noticed which in popular culture define or distinguish something. It can represent subtle differences in states.

A complete description is created and used in scientific disciplines as technical terminology. It may be representable as a set or vector of qualities.

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6. Explanation

a statement which points to causes, context, and consequences of some object, process, state of affairs, etc., together with rules or laws that link these to the object. Some of these elements of the explanation may be implicit.

only be given by those with understanding of the object which is explained.

In scientific research, explanation is one of three purposes of research (other two being exploration and description).

the discovery and reporting of relationships among different aspects of studied phenomenon.

Some different types of explanations: Deductive-nomological, Functional, Historical, Reductive, Teleological

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7. Prediction (forecast) (1)

Latin præ- "before" plus dicere "to say")

a statement or claim that a particular event will occur in the future.

(1) Informal prediction (hypothesis)

often confused with informed guess or opinion.

A prediction of this kind might be valid and useful if the predictor is a knowledgeable person in the field and is employing sound reasoning and accurate data. Large corporations invest heavily in this kind of activity to help focus attention on possible events, risks and business opportunities, using futurists. Such work brings together all available past and current data, as a basis on which to develop reasonable expectations about the future.

(2) Opinion Polls

In politics it is common to attempt to predict the outcome of elections (or assess the popularity of politicians) through the use of opinion polls.

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(3) Supernatural (prophecy)

Predictions have often been made, from antiquity until the present, by resorting to paranormal or supernatural means, such as prophecy or by observing omens. Disciplines including water divining, astrology, numerology, and fortune telling, along with many other forms of divination, have been used for centuries or even millenia to predict or attempt to predict the future. So far none of these means of prediction have been proven under controlled conditions and are heavily criticised by scientists and skeptics.

(4) Anticipatory science forecasts

In a scientific context, a prediction is a rigorous (often quantitative) statement forecasting what will happen under specific conditions, typically expressed in the form If A is true, then B will also be true. The scientific method is built on testing assertions which are logical consequences of scientific theories. This is done through repeatable experiments or observational studies.

7. Prediction (forecast) (2)

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8. Hypothesis (1)

Greek, hypotithenai meaning "to put under" or "to suppose"

a suggested explanation of a phenomenon or reasoned proposal suggesting a possible correlation between multiple phenomena.

a scientific hypothesis:

(1) The scientific method requires that one can test a scientific hypothesis.

Scientists generally base such hypotheses on previous observations or on extensions of scientific theories.

(2) A hypothesis requires more work by the researcher in order to either confirm or disprove it. In due course, a confirmed hypothesis may become part of a theory or occasionally may grow to become a theory itself.

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8. Hypothesis (2)

(3) Normally, scientific hypotheses have the form of a mathematical model. Sometimes, but not always, one can also formulate them as existential statements, stating that some particular instance of the phenomenon being studied has some characteristic and causal explanations, which have the general form of universal statements, stating that every instance of the phenomenon has a particular characteristic.

(4) Any useful hypothesis will enable predictions, by reasoning (including deductive reasoning). It might predict the outcome of an experiment in a laboratory setting or the observation of a phenomenon in nature.

(5) The prediction may also invoke statistics and only talk about probabilities.

Karl Popper : "a hypothesis must be falsifiable." "a proposition or theory cannot be called scientific if it does not admit the possibility of being shown false."

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Types of hypothesis

(1) A proposition may take the form of asserting a causal relationship (such as "A causes B").

If a particular independent variable is changed there also a change in a certain dependent variable. : an "If and Then" statement

(2) A hypothesis about possible correlation does not stipulate the cause and effect per se, only stating that 'A is related to B'.

Causal relationships can be more difficult to verify than correlations, because quite commonly intervening variables are also involved which may give rise to the appearance of a possibly direct cause-and-effect relationship,

(3) Also, a mere observation of a change in one variable, when correlated with a change in another variable, can actually mistake the effect for the cause, and vice-versa (i. e., potentially get the hypothesized cause and effect backwards).

8. Hypothesis (3)

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(4) Empirical hypotheses that experimenters have repeatedly verified may become sufficiently dependable that, at some point in time, they become considered as "proven".

(5) While some people are tempted to term such hypotheses "laws", this would be a mistake since the nature of a hypothesis is explanatory and the nature of a law is descriptive. A more accurate way to refer to such repeatedly verified hypotheses would to simply refer to them as "adequately verified", or "dependable".

8. Hypothesis (4)

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Evaluating hypotheses

The hypothetico-deductive method demands falsifiable hypotheses, framed in such a manner that the scientific community can prove them false (usually by observation).

As an example:

(1) Someone who enters a new country and observes only white sheep might form the hypothesis that all sheep in that country are white. It can be considered a hypothesis, as it is falsifiable.

(2) Anyone could falsify the hypothesis by observing a single black sheep. Provided that the experimental uncertainties are small, and provided that the experimenter has correctly interpreted the statement of the hypothesis, finding a black sheep falsifies the "white sheep only" hypothesis. This sort of example provides the easiest way to understand the term "hypothesis".

8. Hypothesis (5)

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researchers weighing up alternative hypotheses may take into consideration:

* Testibility -compare falsifiability

* Simplicity

* Scope - the apparent application of the hypothesis to multiple cases of phenomena

* Fruitfulness - the prospect that a hypothesis may explain further phenomena in the future

* Conservatism - the degree of "fit" with existing recognised knowledge-systems

8. Hypothesis (6)

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9. Generalization (1)

a foundational element of logic and human reasoning.

the essential basis of all valid deductive inference.

The concept of generalization has broad application in many related disciplines, sometimes having a specialized context-specific meaning.

For any two related concepts, A and B; A is considered a generalization of concept B if and only if:

* every instance of concept B is also an instance of concept A; and

* there are instances of concept A which are not instances of concept B.

For instance, animal is a generalization of bird because every bird is an animal, and there are animals which are not birds (dogs, for instance).

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Hypernym and hyponym

(1) generalization versus specialization (or particularization)

(2) A hypernym as a generic - a class or group of equally-ranked items,

such as tree does for beech and oak; or ship for cruiser and steamer.

a hyponym - one of the items included in the generic,

such as lily and daisy are included in flower, and bird and fish in animal.

(3) A hypernym is superordinate to a hyponym, and •a hyponym is subordinate to hypernym.

9. Generalization (2)

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10. Prescriptionvarious meanings.

suggesting an alternative or policy for the better present and future

Medical prescription - written by a health care professional to a pharmacist

Eyeglass prescription - written by an ophthalmologist or an optometrist

Linguistic prescription - the laying down of normative language rules

Presciription drug - a drug available only by a medical prescription

Prescriptive period - similar to statute of limitations, •applied to periods during which rights and obligations are legally enforceable

Prescription (law) - a doctrine in international law analogous to adverse possession where sovereignty over a territory is transferred from one state to another through prolonged acquiescence by the original sovereign of the recipient state's actions.

Period of Prescription, a civil law system analoge to the common law institute of a statute of limitations