What Is the Assumption of the Scientific Approach to Research

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Introduction to the Scientific Method

Robert Stufflebeam: Author

Empirical claims

An epistemology is a theory of knowledge. Mod science is predicated on the epistemological view called empiricism. Co-ordinate to this view, we are non born knowing anything about "the earth." Empiricists acknowledge that we are born knowing how to do sure things due to our instincts and reflexes (eastward.yard., to cry, to eat, to perceive, etc.). But insofar as knowing that anything is true, empiricists believe that the mind is a "bare slate" -- or "tabla rasa" -- echoing the view championed by the empiricist philosopher John Locke in his An Essay Apropos Man Agreement(1690).

Then, if we are non built-in with knowledge about the world, how is it acquired? In a give-and-take, feel -- from our observations and perceptions, too as those of others. Knowledge gained through experience is chosen empirical knowledge. Science contributes to our empirical knowledge past providing the theoretical frameworks and enquiry methods within which nosotros are able to depict, to explain, and to predict the nature of "the world" successfully. And make no error nigh it. Science has been very successful.

Yet despite the deep agreement of the world that nosotros take gained through science, there is an important feature of empirical knowledge that is worth noting at the outset. It is expressed as the claim in the following statement:

So, what should we conclude from this? That we exercise non know anything nigh the world? That science is unreliable? That we should not believe what science textbooks teach u.s.? It may be comforting to hear that none of these things follow. But to see why this is so, you need to understand something about empirical claims -- assertions virtually how the globe was, is, or will exist. And the beginning thing to annotation is that every empirical claim is a contingent statement -- an exclamation that is neither necessarily true nor necessarily false. Then, for any contingent argument, information technology COULD be truthful, it COULD exist false. And whether a contingent statement is true depends on (or is "contingent" upon) whether what it asserts accords with the way the "the earth" is. To put it baldly, if what a contingent statement asserts corresponds to "the world" in terms of either significant (for words) or reference (for objects), then the statement is true. If this correspondence is not present, then the statement is false.

While this accounts for whether a contingent statement (or empirical claim) is truthful, information technology does not business relationship for how nosotros know it. Since our knowledge about the world (empirical noesis) depends on our ability to tell whether a contingent statement is true, a dandy deal hinges upon the reply to this question: How practice we know whether an empirical merits is truthful or false? Unsurprisingly, experience . Experience provides us with the evidence (justification) for believing that certain statements about the earth are true while others are imitation. For example, consider the following empirical claim:

If someone's brain leaves his trunk, he will die.

Is this claim true? Yes, we believe then. How exercise nosotros know? Well, for starters, there has not been a unmarried documented case in human history where an individual lost her encephalon and continued to live. And since experience has also taught the states that brains regulate the respiratory and other bodily systems that are necessary for life, the prove for the truth of this merits is overwhelming.

Notwithstanding, does all our "overwhelming" evidence guarantee that this claim will remain true in the futurity? No. After all, in much the same way that we can now supplant a "real" heart with an artificial one, is information technology not possible that we could one day supercede a "real" encephalon with an artificial one? The betoken is non whether such a procedure is probable, but whether information technology is possible. And it is. Hence, the in a higher place claim is neither necessarily true nor guaranteed to be true. Given what nosotros know most homo history and the nowadays state of brain transplant applied science, the above claim is true. But it could one day turn out to exist simulated. Here is the rub: The same can exist said for EVERY empirical merits. The reason for this is that no accumulation of empirical evidence (experience) will EVER guarantee that events in the future will occur as they have in the past. Consequently, non one empirical claim (or "fact" about anything in the world) is guaranteed to be true. This lack of a guarantee is called the problem of consecration. And with respect to knowledge about the future based on past experience every bit bear witness, it is insurmountable.

But this problem is non limited to empirical claims most the future alone. Rather, it likewise applies to empirical claims near both the present and the past. For case, the best empirical evidence currently bachelor leads us to believe that the post-obit empirical claim is true:

Neil Armstrong was the kickoff human to walk on the moon.

While the evidence for the truth of this merits is overwhelming, even "overwhelming" evidence can pb us to believe that a claim is true when it is in fact fake. Such was the instance with this claim:

Earth is the eye of the universe.

Although the best prove for centuries led people to believe otherwise, they were mistaken nevertheless. And equally there are many fields of science that are littered with bodies of testify that misled people to believe claims that were in fact false, there is every reason to believe that some of what we at present believe to be truthful will be proven simulated as well. The to a higher place merits about Neil Armstrong is a candidate for this. Granted. It would take a cracking deal of evidence to convince u.s.a. that this conventionalities is false. Nevertheless, as it is possible that NASA perpetrated an elaborate hoax, it is possible to abnegate the "fact" that Neil Armstrong was the first man to walk on the moon. Indeed! In that location is not a unmarried empirical claim that is immune from being proven simulated. Not one! Then, fifty-fifty though information technology is very, very improbable that certain empirical claims will ever be proven false, it is possible that they could exist proven false. And in principle, this is possible for EVERY empirical merits.

Thus, in social club to justify our claims about the mode "the world" was, is, or volition be, we must rely upon empirical evidence. Just since our empirical evidence is no more guaranteed to be true than the claims our evidence is offered to testify, nosotros are left with the inescapable conclusion that our noesis about the world volition never be perfect, sure, and unrevisible. Empirical knowledge simply does not work that manner. As such, here is the fundamental message to accept home from this discussion: There are limits to what scientists can detect, sympathize, explain, and predict based on experience and observation as evidence. Hither is another: It is NOT a weakness of science that no empirical claim is immune from possible refutation. Afterward all, the reason that so many empirical claims (and theories) deserve to be believed is that they have (thus far) survived the scrutiny of researchers who consistently try to abnegate them through the scientific method. Let u.s. plough our attending to how this occurs.

How do scientists reason?

It is non actually the example that scientists reason differently than nonscientists. Reasoning is reasoning. Still, our focus is on scientific reasoning, specifically, on how empirical evidence bears upon the truth of scientific hypotheses. Toward this stop, y'all need to understand a bit more than about the nature of arguments and the role they play in the scientific method.

Arguments

As noted in the previous section, every empirical claim is either true or simulated (but not both). And making an empirical claim is easy. After all, doing so requires merely asserting something about the manner the world was, is, or will be. Here are two examples:

World is apartment.

It is fake that Earth is apartment.

Tin can both of these empirical claims exist truthful? No. As they are contradictory, exactly one is true and exactly one of false. Just which is which? Most of united states believe that the 2nd argument is the true ane. Not everyone agrees, particularly members of the Flat Earth Society. At present is not the time to evaluate the reasonableness of the evidence that "justifies" their belief, for the point is this: In that location volition e'er exist an audience for whom a merits is obvious. Again, making claims is like shooting fish in a barrel, especially in the presence of an audience who is predisposed to accept your claim is true. The hard role about making claims is convincing an audience who sees the earth differently. In that location are innumerable occasions in scientific discipline when a researcher must try to show, to persuade, to convince, or to prove to an audience that a particular merits is true. To succeed, the researcher must do more than merely assert her claim. Rather, she must argue for it.

But what are arguments? Well, "good" ones are the medium through which we programme, explain, persuade, convince, and show things successfully through linguistic communication. And not but does every argument in the universe consist of a set of statements, every argument, no thing how complicated, consists of just 2 functional parts. I is the merits, the statement asserted to be true. The other is the evidence, the statement(s) purporting to show that the claim is true. It really is that simple.

But while arguments are used for many purposes in science -- to explicate, to persuade, to convince, to predict, to demonstrate, and to prove things through linguistic communication -- it is not the case that the hallmark of scientific discipline is offering arguments. Instead, the authentication of science is conducting tests. Scientific tests are a kind of statement that requires performing an experiment, investigation, or research for the sake of resolving an empirical question. As you lot might expect, what makes a question an empirical ane is the need for feel and observation to answer information technology. Consider this one:

How many planets are at that place in our solar system?

Is it possible to answer questions of this sort correctly without relying upon evidence from experience and observation? No (fifty-fifty "guessing" qualifies equally experience). Yet neither is it possible to do so reliably without looking in the right place. Suppose that y'all were a researcher attempting to resolve how bats perceive the world through echolocation (a kind of "sonar"). Would you stand any chance of success by observing weather patterns in Antarctica, writing a pattern recognition reckoner plan, or investigating the effects of vodka upon feline perceptual abilities? Of course not. Successfully resolving an empirical question requires conducting non just whatsoever scientific test, only 1 that results in prove that is relevant to the question. Not all experiences and observations are relevant to all questions. Neither are all research methods and techniques.

So, when attempting to settle an empirical question, how does a researcher decide where to observe, which experiences to tape, and what evidence is relevant? The answer has two parts.

First, since it is impossible to conduct a scientific exam without the employ of a detail experimental technique or method, the method chosen by a researcher volition decide which experiences to discover and tape. For instance, suppose that y'all wanted to know whether you lot take a fever. Because y'all presume that your old-fashioned thermometer is in good working social club, you accept your temperature. What exercise you look for? The mercury level against the temperature scale? Of course. While you may also detect the manufacturer of the thermometer, the colour of its numbers, and a host other things nigh the musical instrument, your having chosen an one-time-fashioned thermometer makes the observations that are relevant to this test different from the observations that are relevant to a exam using an electronic thermometer. Obviously.

2nd, even when a researcher does non do so consciously, she decides where to observe, which experiences to tape, and what evidence is relevant by making inferences. Every inference is the conclusion of a "mini" statement. Therein lies the relation between arguments and tests: It is through arguments that researchers identify the empirical consequences of their assumptions. Because scientific tests are impossible without the show-claim relation nowadays in every argument, arguments are an inseparable part of the scientific method.

The scientific method

Although empirical questions engender scientific tests, strictly speaking, scientific tests are not tests of empirical questions. Later on all, questions are neither true nor imitation. Empirical statements, yes, they have truth-values, simply empirical questions do not. And so, because scientific tests are conducted in order to broaden our cognition about the world, and knowledge about the world is expressed via true contingent statements, a scientific test is a test of a contingent statement. What that statement is will be an reply to an empirical question. Regardless of whether that respond is tentative, "unproven," or an established "fact," any statement field of study to an empirical examination is an hypothesis. Hypothesis testing lies at the heart of the scientific method. What follows is an outline of the procedure. And to make things more than physical, suppose that you are a medical doctor. A patient arrives who you have never earlier seen and the patient claims to be pregnant.

Stride ane: Cull AN EMPIRICAL QUESTION

Considering scientific tests touch on resolving empirical questions, simply not necessarily philosophical ones, conducting scientific enquiry requires dealing with a question that can be settled past feel and observation.

For our test, the empirical question (Q) is this: Is the patient pregnant?

Step 2: CHOOSE A HYPOTHESIS

The fundamental to a scientific examination is the hypothesis (H). Unremarkably, the hypothesis is the argument asserting what a researcher assumes is the correct reply to whatever empirical question is motivating the research. But since scientists sometimes examination competing hypotheses or those of their colleagues, from a logical indicate of view, it makes no difference whether a scientist "actually" believes in the truth of the hypothesis beingness tested. The simply thing that matters is that something is causeless to account for, to explain, or to otherwise be the correct reply to the question, even if only for the sake of argument.

For our test,

H = The patient is pregnant.

And H is the first empirical testify statement inside the argument of the test:

i. Let'due south presume that H.

STEP 3: Cull AN EXPERIMENTAL TECHNIQUE/METHOD

No empirical question can be settled without reports of experience. That is, the test must produce something that we tin detect with our five senses (something nosotros can encounter, hear, affect, smell, or taste). Thus, testing an hypothesis requires choosing a method that produces observable data. The information may be directly observable by the researcher, every bit is the case when a medico examines a patient and relies solely upon what she sees, hears, and feels without the help of any instruments. Indirectly observable data is obtained through the employ of an instrument. For example, you can indirectly observe (a) someone's temperature via a thermometer, (b) a cell'due south membrane via a microscope, (c) a distant galaxy via a telescope, etc.

And so, what technique/method should we choose for our examination? Let'due south opt for a blood exam -- a test measuring the amount of HCG (human chorionic gonadotropin) in the blood. HCG is the hormone made within a woman'south body later an egg is fertilized and starts to grow into an embryo. Incidentally, HCG is also detected in urine pregnancy tests.

Pace four: IDENTIFY THE ASSUMPTIONS

While the hypothesis is an assumption (A), the hypothesis will NEVER be the merely assumption fabricated when the scientific method is used. The reason for this is that EVERY evidence statement within an argument is an assumption -- a statement whose truth is being presupposed only non proven. Afterward all, you lot can't do everything at the same fourth dimension. You lot bear the brunt of showing that your merits is true when you argue, not for showing that your evidence is truthful. Granted, if someone challenges your evidence, you may then be required to give another argument to support your evidence. Merely that would exist a different argument. Y'all tin simply practise ane thing at a time. Thus, assumptions are a necessary office of every statement.

The boosted assumptions may be either explicit or implicit. The explicit assumptions volition exist the additional stated show statements within the statement. Ane most common show statements of this sort are scientific laws -- statements to the effect that in such-and-such part of the universe, whenever conditions of a detail kind occur, F, then, all things being equal, weather condition of another kind, G, volition besides occur. Scientific theories are another kind of explicit assumption commonly found amid the stated evidence statements in arguments of this sort. A scientific theory is a testable set of full general principles that explain a range of observed phenomena.

Implicit assumptions, while not stated evidence statements, are evidence statements still. And EVERY statement (and question) carries implicit assumptions. For example, consider our hypothesis. If you every bit the physician assume that the patient is pregnant, then you are implicitly bold that each of the following statements is also true:

• The patient exists.
• The patient is a female.
• Some patients tin can exist pregnant.
• Only females can be pregnant.
• It is possible for the patient to be pregnant.

Moreover, every research method carries implicit assumptions too. Thus, to the list of implicit assumptions just identified, nosotros can add the post-obit:

• Blood exists and then do sex hormones.
• It is possible to extract a patient'south blood.
• Information technology is possible to test claret for hormone levels.
• HCG is a hormone.
• HCG is made when and but when a adult female is pregnant.
• The presence of HCG is a reliable indicator of pregnancy.

At present, are any of these implicit assumptions unreasonable? No. Consequently, practise not consider assumptions to be "bad" prove. By all means, consider dubious assumptions to be "bad," merely 'dubious supposition' and 'assumption' do non mean the same thing.

Of course, every theory carries implicit assumptions likewise, just I suspect yous get the idea.

Although I want yous to empathize the logical structure of the scientific method, it makes no sense to complicate things unnecessarily. Hence, rather than identify each explicit assumption as a separate evidence statement, let'southward stand for the prepare of auxillary assumption every bit '{A}'. Here is the argument and so far:

i. Let's assume that H is true.
2. Let'southward assume that {A} is true.

And if the hypothesis and our gear up of other assumptions is each truthful, we may infer that the following conjunction must be true too:

3. H and {A}.

STEP 5: INFER THE LOGICAL CONSEQUENCES OF THE ASSUMPTIONS

Whether the scientist does so consciously or non, it is at this point when she asks herself the post-obit question:

If my hypothesis and other assumptions are true, then what outcome must I discover in the globe?

Later on all, if the assumptions are truthful, and so certain observable events must occur under the specific circumstances determined by the option of method. The logical consequences of the assumptions are those appreciable events (O).

Annotation that the researcher is not interested in what she may observe, but what she must discover. For case, if our hypothesis AND our other assumptions are true, does it follow that the patient must take a distended belly? No. The patient may be only i month pregnant or also large for her pregnancy to be seen. Does it follow that the patient volition have experienced morning sickness or cravings? No. It is possible to be significant and feel neither of those common symptoms.

And then, if the truth of our hypothesis AND our auxiliary assumptions does not entail either of these observations, what exercise they entail? What must nosotros observe? While there are several obvious candidates, the observable event (O) most relevant for our purposes is this: HCG should be detected in the patient's claret.

Here is the logical structure of the examination so far:

ane. Let's presume that H.
ii. Let's assume that {A}.
three. H and {A}.
4. If H and {A}, then O.

Step v: PERFORM THE TEST AND RECORD THE DATA

Having set up the exam (in the grade of an argument) to place what should be observed if the hypothesis and other assumptions are truthful, it is at this point when the test is completed and the observations ("data") are recorded. There are two possibilities. Either what was observed was what should take been observed, or, what should have been observed was not observed. Either mode, having recorded what was observed, the testify is at present consummate. The concluding step in a scientific examination is to evaluate the hypothesis in relation to that testify.

But an empirical argument consists not just of bear witness. An empirical claim is supposed to follow from that evidence. Because a keen deal of emphasis has been placed on how scientists cull their evidence (assumptions), you lot may be wondering why no attention has been directed at the claim itself. The reason for this is that a scientist uses the scientific method to decide whether his hypothesis is true. While this may audio obvious, there is a significant difference between making a claim and so assuming certain show in order to show that the claim is truthful, on the 1 hand, and assuming the truth of an hypothesis (and other assumptions) in social club to see what follows. The former characterizes the use of virtually all argumentative reasoning exterior the context of a scientific test. The latter characterizes one of the defining features of existence a "proficient" scientist; namely, being willing to abandon an hypothesis if the evidence does not support it. Contrary to popular conventionalities, it is not the purpose of the scientific method "to prove" an hypothesis, but to brand certain assumptions and observations (evidence) explicit in gild to maximize the chances of evaluating an hypothesis accurately.

STEP 6: EVALUATE THE HYPOTHESIS

Empirically speaking, whether what should have been observed was observed is the crucial piece of evidence that bears upon whether the hypothesis is true. As noted above, there are two possibilities. One is positive (because what was observed was what should accept been observed). The other is negative (because what should have been observed was not observed). Logically speaking, things are non quite so unproblematic. Let'south deal with the easiest example first.

Negative case

It is oft said that negative data (non seeing what should have been observed) falsifies the hypothesis. Only that is not necessarily true. What does logically follow from negative data is H and {A} are not both true. In other words, either the hypothesis is false or at least one member of the set of auxiliary assumptions is faux. A test with negative data (evidence statement 5) results in the following argument:

Equally this argument is valid, the merits follows necessarily from the show. And considering information technology is impossible for a valid argument to take true evidence and a fake claim, if prove statements 1-5 are true, then necessarily the claim must be true too. Therein lies the value of validity: If an statement is valid AND all its evidence is true, then the claim MUST be true as well (non on its own necessarily, just simply in relation to the show).

Then, if our test results were negative, it follows that either the patient is not significant or one of our other assumptions is faux ("dubious"). Which is more than reasonable to believe? As is the case with most empirical research, it is unremarkably the hypothesis that is less well accepted than the methodological, theoretical, and other auxillary assumptions. Thus, a negative test usually results in a hypothesis being abandoned or revised. And since the empirical question motivating the enquiry has not been resolved, negative tests lead to farther research. For that reason, negative data is non a "bad" thing. Also, it is the scientist's task to discover truths about the world, not to defend a pet hypothesis confronting unfavorable evidence. Indeed! Where it is not possible to examination an hypothesis (or theory), it is not possible to falsify information technology. Hypotheses (or theories) that are "true" no matter what can be observed in the globe are non scientific (east.g., star divination). Rather, such hypotheses (or theories) are pseudoscientific. Pseudoscience is always "bad" science.

Positive case

It is often said that positive information (seeing what should have been observed) verifies the hypothesis, showing that it is true. Hence, a test with positive information (evidence statement 5) results in this argument:

Merely accept a closer look at this argument. Does annihilation strike you as suspicious? Hopefully so, namely, that the beginning bear witness argument and the merits are ane and the same statement. Do you run into this? It may aid to note that while the expression 'let's assume that' make the beginning and last statements unlike sentences, what each of those sentences asserts is 1 and the same statement -- H. Whenever something like this occurs, the argument is said to be circular (or beg the question). Because it is logically impermissible to presuppose the truth of your claim amongst your evidence when y'all are trying to show that your claim is true, every circular argument is a bad argument. Only since it is impossible for the evidence to be true and for the merits to be fake, owing to its circularity, every circular argument is a valid argument. Notwithstanding, we know this before we fifty-fifty perform the test. We can simply ignore statements 4 and v because the merits follows directly from argument i (as well as statement 3). And as the observed "data" is logically irrelevant to the truth of the merits, information technology makes no sense to say that the ascertainment verifies the hypothesis.

If in that location is a good statement to exist constructed hither, how are we to practise it? Showtime we have to recognize that there are unlike types of arguments. Some arguments are so structured that the truth of the premises (the assumptions) guarantees the truth of the claim being defended. In such deductive arguments, the claim necessarily follows from the assumptions. But there are many good arguments that do not accept this feature. In fact, most of the arguments given to support scientific claims -- even the really good arguments -- exercise not take this holding. This is because about scientists offer arguments in which the claim being considered is supported by bear witness that makes the claim probable (often highly probable) just that does non logically guarantee the merits. Nosotros call arguments of this kind inductive arguments. Because science is concerned with learning contingent facts about the world that tin can never be guaranteed to exist true, the strongest back up that can always be offered for these claims is the anterior back up that comes from anterior arguments. If nosotros eliminate show statements 1-3, the resulting argument no longer begs the question. Moreover, it captures the rationale for believing that the positive information (show statement 2) verifies the hypothesis:

For example, consider the empirical claim that the lord's day volition rise tomorrow. Nonetheless 5 billion or so years of prove for the truth of this claim, due to the problem of induction, there is no guarantee that the sunday will ascent tomorrow. It is possible that aliens from some other galaxy volition blow the sun out of the sky tomorrow. If they do, the sun won't rise. Simply that isn't likely. Does the lack of a guarantee mean that the claim is not very very likely to be true? No. And clearly it is very very likely to be truthful. Therein lies the value of induction.

Hence, inductively, it does make sense to say that the "observed" data verifies the hypothesis. While it does not follow that the hypothesis is true, information technology does follow that the evidence justifies our belief that information technology may be truthful. In our test, would a positive claret test guarantee that the patient is pregnant? No. The patient may have a hormonal imbalance, the exam results may have been switched with some other patient, etc. Nevertheless, unless there are reasons for assertive that i of these possibilities occurred, we would exist justified to believe that our hypothesis is truthful. All things being equal, the same holds for other "verified" hypothesis. But since no empirical claim is necessarily truthful, remember, no verified hypothesis, "fact," or any other statement well-nigh the earth is immune from possible refutation.

Here ends your introduction to the scientific method and how scientific tests contribute to our knowledge about "the globe." The principle benefit of having explored the general nature of scientific research is that y'all should be sensitive non just to the limits of scientific research, merely to the part of assumptions (theoretical, methodological, etc.) within both arguments and scientific tests.

FUNDING:

This module was supported by National Scientific discipline Foundation Grants #9981217 and #0127561.

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Source: https://mind.ilstu.edu/curriculum/scientific_method/scientific_method.html

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