CH 9 (Inference to the Best Explanation)

prior probability

-the plausibility of a theory -some theories have higher prior probability than others -we assess the theories to see which is ''best'' in relation to the total evidence P(H) is the prior probability of H, i.e., the probability of theory H just in relation to our background information B, prior to or independent of any evidence E that needs to be explained. --> In other words P(H/B) -that is, how antecedently probable is the theory before we conduct an investigation

A theory judged by the criteria of adequacy to be the best explanation for certain facts is worthy of our belief, and we may legitimately claim to know that such a theory is true. But the theory is not then necessarily or certainly true in the way that a sound deductive argument's conclusion is necessarily or certainly true. Inference to the best explanation, like other forms of induction, cannot guarantee the truth of the best explanation. That is, it is not truth-preserving. The best theory we have may actually be false. Nevertheless, we could have excellent reasons for supposing our best theory to be a true theory.

Although the prior probability of H1 may be greater than that of H2, the explanatory power of H2 may be great enough to overcome the low prior probability of H2. On balance, then, we can conclude that probably H2 is the better theory: it has the greatest overall balance of prior probability and explanatory power! It may have a lower prior probabolity with respect to background information B, but it has much greater explanatory power with respect to the evidence in E. LOOK FOE THE ''GREATEST OVERALL BALANCE''

Although the prior probability of H1 may be greater than that of H2, the explanatory power of H2 may be great enough to overcome the low prior probability of H2. On balance, then, we can conclude that probably H2 is the better theory: it has the greatest overall balance of prior probability and explanatory power! It may have a lower prior probabolity with respect to background information B, but it has much greater explanatory power with respect to the evidence in E. LOOK FOR THE ''GREATEST OVERALL BALANCE''

What are the following an example of? -To stop the chemical reaction, she added sulfur. -He paid his taxes online by downloading the forms then using his care number -She opened up the engine, then examined the valves, then checked the cylinders.

procedural explanations

True or False. Just weight the evidence for each theory and the theory with the most evidence wins.

False -evidence alone cannot be the sole criterion by which we assess explanations

the theories or hypothesis introduced to explain the evidence E

H1, H2, H3...Hn

What are 4 different kinds of explanations?

procedural explanations interpretive explanations teleological explanations theoretical explanations

If a theory is untestable--if there's no possible procedure for checking its truth--then it's worthless as an explanatory theory. We can assign no weight to such a claim. Another way to look at it is that: theories are explanations and explanations are designed to increase our understanding of the world. But an untestable theory doesn't and cannot explain anything. It is equivalent to saying that an unknown thing with unknown properties acts in an unknown way to cause a phenomenon, which is the same things as offering no explanation at all.

If we show that a theory contains a contradiction, we have refuted it. A theory that implies that something both is and is not the case cannot possibly be true. If a theory is externally inconsistent, we have reason to believe that it's false. Suppose you leave your car parked on the street overnight and the next morning discover that the wind shield is broken, there's blood on the steering wheel and there's a brick on the front seat. And let's say your friend offers this theory to explain the facts: Someone threw a brick through your windshield. His theory accounts for the broken windshield and the brick but not the blood on the steering wheel. You'd likely toss out his theory and look for on that was complete.

In constructive perception what we perceive (see, hear, feel, etc) is determined in part by what we expect , know, or believe. Studies have shown that when ppl expect to perceive a certain stimulus, they often do perceive it, even if there is no stimulus present. The phenomenon of constructive perception then can be used to explain many instances in which ppl seem to perceive something when it's not really there or when it's actually very different from the way ppl think it is. One kind of case that investigators sometimes explain as an instance of constructive perception is the UFO sighting. Many times ppl report seeing lights in the night sky that look to them like alien spacecraft, and they explain their perception by saying that the lights were caused by alien spacecraft. So we have 2 theories to explain the experience: constructive perception and UFOs from space. If these 2 differ only in the degree of scope provided by each one, we much conclude that the constructive perception theory is better, The constructive perception theory can explain not only UFO sightings but all kinds of ordinary/extraordinary experiences--hallucinations, feelings of an unknown presence, identification of crime suspects, etc. The UFO theory however is designed to explain just one thing: an experience of seeing strange lights in the sky.

What are the following an example of? -The wall switch is there so you can turn off the lamp from across the room -These wildflowers are here as a blessing from God -The heart circulates and oxygenates the blood

teleological explanation

refers to H having observational consequences

testability

the degree to which a hypothesis has observational consequences (predictions or expectations) other than those it was originally formulated to explain. -the theory is typically conjoined with auxiliary assumptions that are independently verifiable.

testability

whether there is some way to determine if a theory is true

testability

Modesty

(roughly) a measure of the content of the hypothesis, i.e., how much it says, -other things equal the less the hypothesis says, the more likely it is to be true and so the greater its antecedent probability.

What is a causal explanation? Are causal explanations used in inference to the best explanation?

- a kind of theoretical explanation -like all theoretical explanations, causal explanations are used in inference to the best explanation

Under what circumstances can an inference to the best explanation be deemed strong? Cogent?

-If the explanation for the existence or nature of a state of affairs really is the best (the one most likely to be true), then the argument is inductively strong. -And if the premises are also true, then the argument is cogent. If cogent, we are justified in believing that the explanations for the phenomena are in fact correct.

final probability

-P (H/E)= the probability of H given our evidence E or it can also be written as P (H/B&E) -It is equal to the prior probability of a theory times the explanatory power of the theory: P(H/E)= P(H) x P(E/H) -we assess the theories to see which is ''best'' in relation to the total evidence (B&E) -we say the final probability of one theory is greater than that of another theory iff one of the theories has the greater overall balance of prior probability and explanatory power.

What is the criterion of conservatism?

-a criterion of adequacy for judging the worth of theories. A conservative theory is one that fits best with our established beliefs -says that other things being equal, the best theory is the one that fits best with our established beliefs -everything considered, the more conservative a theory is, the more plausible it is -OTHER THINGS EQUAL, THE MORE CONSERVATIVE THE HYPOTHESIS IS, THE MORE LIKELY IT IS TO BE TRUE, I.E., THE GREATER ITS PRIOR PROBABILITY

What is the criterion of fruitfulness?

-a criterion of adequacy for judging the worth of theories. A fruitful theory is one that makes novel predictions -Other things being equal, theories that successfully predict previously unknown phenomena are more credible that those that don't. They are said to be fruitful, to yield new insights that can open up whole new areas of research and discovery. This fruitfulness suggests that the theories are more likely to be true. -OTHER THINGS EQUAL, THE MORE FRUITFUL A HYPOTHESIS/THEORY, THE GREATER ITS EXPLANATORY POWER

What is the criterion of simplicity?

-a criterion of adequacy for judging the worth of theories. A simple theory is one that makes minimal assumptions. -other things being equal, the best theory is the one that is simplest--that is, the one that makes the fewest assumptions. The theory making the fewest assumptions is less likely to be false b/c there are fewer ways for it to go wrong. Another way to look at it is that since a simpler theory is based on fewer assumptions, less evidence is required to support it. -OTHER THINGS EQUAL, THE SIMPLER THE HYPOTHESIS, THE MORE LIKELY IT IS TO BE TRUE AND SO THE GREATER ITS PRIOR PROBABILITY.

How do you determine ''greater overall balance'' of prior probability and explantory power to determine which theory has the higher final probability?

-by multiplying P(H1/E) > P(H2/E) if and only if P(H1) x P(E/H1) > P(H2) x P(E/H2) the final probability of H1 is greater than that of H2 if and only if the prior probability of H1 times the explanatory power of H1 is greater than the prior probability of H2 times the explanatory power of H2

In what context is abductive reasoning used?

-common everyday experiences -CSI/detective cases -the sciences

What is an interpretive explanation?

-concern the meaning of terms or state of affairs -these explanations seek to understand not something's purpose or cause, but rather its sense or semantic meaning

Suppose theory 1 and 2 are two equally plausible theories explain phenomenon X. Theory 1 can explain X well and so can theory 2. But theory 1 can explain or predict only X, whereas theory 2 can explain or predict X as well as phenomena Y and Z. We could conclude that theory 2 is the better theory b/c it explains more diverse phenomena. That is, it has more ____than the other theory.

scope

the amount of diverse phenomena explained

scope

the range of facts explained by the theory

scope

roughly a measure of the number of independent postulates that comprise a hypothesis

simplicity

the number of assumptions made

simplicity

the number of assumptions, parameters, postulates that the theory makes

simplicity

What are the 3 types of probability statements?

1.) probabilities that we can know a priori (you know the probability before even needing to do the experiment) ex: P (rolling a 6 on a di)=1/6 ex: P (red card/heart)=1 ex: P (heart/red)=1/2 2.) Probabilities that we can establish by frequencies (Look at lots of data to determine the probability) ex: P (iphone detective)=13/890 (do sampling to determine frequency and probability) ex: P (Bob has home fire)=1/1,150 3.) probabilities that we assign subjectively (guestamating) ex: P (Giants will win World Series)= 1/30 ex: P (Giants will win World Series) =1/9 ...your guess is as good as mine

What are risks involved in accepting a nonconservative theory?

1.) the chances of the new belief being true are not good (b/c it has no evidence in its favor, while our well established beliefs have plenty of evidence on their side) 2.) The conflict of beliefs undermines our knowledge (b/c we cannot know something that is in doubt, and the conflict would be cause for doubt) 3.) the conflict of beliefs lessens our understanding (b/c the new beliefs cannot be plausibly integrated into our other beliefs)

What is inference to the best explanation?

=a form of inductive reasoning in which we reason from premises about a state of affairs to an explanation for that state of affairs -AKA ABDUCTIVE ARGUMENT -the premises are statements about observations or other evidence to be explained -the explanation is a claim about why the state of affairs is the way it is -abductive reasoning exhibits a ''why'' and b/c'' pattern. The puzzling facts or phenomena need to be explained by an adequate theory/hypothesis. -they key issue that this type of inference tries to answer is, ''What is the best explanation for the existence or nature of this state of affairs?'' The best explanation is the one most likely to be true, even though there's no guarantee of its truth as there is in deductive inference

What is ''ad hoc''?

=for this--for this special purpose -an ad hoc explanation is introduced for the special purpose of saving a theory from disconfirming evidence (and there is no independent evidence in favor of the introduced explanation) -often make explanation untestable and less simple and thus less credible

What is probability?

=rational degree of belief between o and 1 P( ) stands for probability of ( ) P(B/A) is the conditional probability of B, given A

In what way did Einstein's theory have more scope than Newton's?

A major strength of Newton's theory of gravity and motion was that it explained more than any previous theory. Then came Einstein's theory of relativity, which could explain everything that Newton's theory could explain plus many phenomena that Newton's theory could not explain. This increased scope of Einstein's theory helped convince scientists that it was the better theory

What does it mean for a theory to be testable?

A theory is testable if it predicts something other than what it was introduced to explain.

In science, where inference to the best explanation is an essential tool, usually theories of interest are causal theories, in which events are things to be explained and the proposed causes of events are the explanations.

Assumptions about existence of unknown objects, forces, and dimensions are common in occult or paranormal theories, but they lack simplicity. Theories that posit paranormal entities (that assume the existence of unknown entities) are not simple.

the total evidence

B&E (B together with E)

Before we apply special criteria to determine whether a theory is the best explanation of a phenomenon, we have to make sure that the theory in question meets the minimum requirement for consistency.

Even though an explanation is not an argument, an explanation can be part of an argument--a powerful inductive argument known as inference to the best explanation. It can be the heart of inference to the best explanation. And in this kind of inference, the explanations we use are theoretical explanations.

In step 1 of the TEST formula, we state the theory and check for consistency. Before you can evaluate an explanatory theory, you must express it in a statement that's as clear and specific as possible. Once you do this, you can check to see if the theory meets the minimum requirement for consistency. If it fails the consistency test, you can have no good grounds for believing that it's correct. And obviously, if the theory fails step 1, there's no reason to go to step 2.

In step 2 of the TEST formula, we assess the evidence for the theory. To critically evaluate any theory, you must understand any reasons in its favors--the empirical evidence or logical arguments that may support or undermine it. Essentially, this step involves an honest assessment of the empirical evidence relevant to the truth (or falsity) of the theory. To make this assessment, you must put to use what you already know about the credibility of sources, causal reasoning, and evidence from personal and scientific observations. In this step, you may discover that the evidence in favor of a theory is strong, weak or nonexistent. You may find that there is good evidence that seems to count against the theory. Or you may learn that the phenomenon under investigation did not occur at all. Whatever the case, you must have the courage to face up to reality. You must be ready to admit that your favorite theory has little to recommend it.

In step 3 of the TEST formula, we scrutinize alternative theories. Inference to the best explanation will not help us very much if we aren't willing to consider alternative explanations. Simply examining the evidence relevant to an eligible theory is not enough. Theories can often appear stronger than they really are if we don't bother to compare them with others. This step requires us to have open mind, to think outside the box, to ask if there are other ways to explain the phenomenon in question and to consider the evidence for those theories. Specifically, in this step, we must conscientiously look for competing theories, then apply both step 1 and step 2 to each one of them. This process may leave us with many or few eligible theories to examine. In any case, it's sure to tell us something important about the strength or weakness of competing theories. (Note: many times the criteria of adequacy can help us do a preliminary assessment of a theory's plausibility w/o surveying alternative theories. For example, a theory may do so poorly regarding a particular criterion that we can conclude that, whatever the merits of alternative explanations, the theory at hand is not very credible. Such a clear lack of credibility is often apparent when a theory is obviously neither simple nor conservative).

In step 4 of the TEST formula, we test the theories with the criteria of adequacy. Simply toting up the evidence for each of the competing theories and checking to see which one gets the highest score will not do. We need to measure the plausibility of the theories using the criteria of adequacy. The criteria can help us put any applicable evidence in perspective and allow us to make a judgement about theory plausibility even when there's little or no evidence to consider. By applying the criteria to all the competing theories, we can often accomplish several feats. We may be able to eliminate some theories immediately, assign more weight to some than others, and distinguish between theories that at first glance seem equally strong.

Inference to the best explanation always ''goes beyond the evidence''--it tries to explain facts but does so by positing a theory that is not derived entirely from those facts. It tries to understand the known by putting forth--through inference/imagination--a theoretical pattern that encompasses both the known/unknown. It proposes a plausible pattern that expands our understanding.

True or False. We often run into untestable theories in daily life. Some ppl say that their misfortunes are caused by God or the Devil. Others believe that certain events in their lives happen and are inevitable b/c of fate. Many practitioners of alternative medicine claim that health problems are caused by an imbalance in ppl's chi, an unmeasurable form of mystical energy that's said to flow through everyone.

True

It is possible, of course, that a new theory that conflicts with what we know could turn out to be right and a more conservative theory wrong. But we would need good reasons to show that the new theory was correct before we would be justified in tossing out the old theory and bringing in the new. Science looks for conservative theories, but it still sometimes embraces theories that are departures (called radical departures) from the well-worn, accepted explanations. When this dramatic change happens, it's frequently b/c other criteria of adequacy outweigh conservatism

Just as we do in every day life, scientists often consider several competing theories for the same event or phenomenon. Then through scientific testing and careful thinking, they systematically eliminate inadequate theories and eventually arrive at the one that's rightly regarded as the best of the bunch. Using this form of inference, scientists discover many things that cannot be directly observed. Many ppl in so many areas of inquiry use inference to the best explanation as well. For instance, physicians use it to pinpoint the cause of multiple symptoms in patients. Police detectives use to to track down lawbreakers. Judges/juries use it to determine the guilt or innocence of accused persons. An philosophers use it to asses the worth of conceptual theories,

Just because a theory is implausible doesn't make it false. It can turn out to be true. Just because a theory is plausible doesn't make it true. It may turn out to be false.

What is Bayes' Theorem?

P(H/E)= (P(H) x P(E/H))/ ([P(H) x P(E/H)] + [p(~H) x P(E/~H)]) P(~H)= 1 - P(H)

What is the logical pattern of inference to the best explanation?

Phenomenon Q E provides the best explanation for Q Therefore, it's probable that E is true or H1 has,--of the mutually exclusive and jointy exhaustive set of hypothesis H1,H2...Hn--the greatest overall balance of PRIOR PROBABILITY and EXPLANATORY POWER. [probable] H1 is true, i.e., has a probability greater than 0.5

Scope is often a crucial factor in a jury's evaluation of theories put forth by the prosecution and defense. The prosecution will have a very powerful case against the defendant if the prosecutor's theory (that the defendant did it) explains all the evidence and many other things while the defense theory (innocence) does not. The defendant would be in big trouble if the prosecutor's theory explains the blood on the defendant's shirt, the eyewitness accounts, the defendant's fingerprints on the wall and the sudden changes in his usual routines--and the innocence theory renders these facts downright mysterious

Skipping step 3 of the TEST formula is an extremely common error in the evaluation of explanations of all kinds. It's a supreme example of many types of errors, overlooking evidence, preferring available evidence, including looking only for confirming evidence, and denying evidence. Step 3 also goes against our grain. The human tendency is to grab hold of a favorite theory and to halt any further critical thinking right there. Our built-in-bias is to seize on a theory immediately b/c we find it comforting or b/c we just ''know'' it's the right one, then ignore or resist all other possibilities. The result is a greatly increased likelihood of error and delusion and a significantly decreased opportunity to achieve true understanding. Failure to consider alternative theories is the archetypal mistake in inquiries in the paranormal or supernatural. The usual pattern is this: (1) you come across an extraordinary or impressive phenomenon. (2) You can't think of a natural explanation of the facts, and (3) you conclude that the phenomenon must not be natural but paranormal or supernatural. This conclusion, however, would be unwarranted. Just b/c you can't think of a natural explanation doesn't mean that there isn't one. Just b/c you can't think of a natural explanation doesn't mean that there isn't one. You may simply be unaware of the correct natural explanation.

Suppose your electric clock stops each time you touch it. One theory to explain this event is that there is an electrical short in the clock's wiring. Another theory is that an invisible, undetectable demon causes the clock to stop. The wiring theory predicts that if the wiring is repaired, the clock will no longer shut off when touched. So it is testable--there is something that the theory predicts other than the obvious fact that the clock will stop when you touch it. But the demon theory makes no predictions about anything, except the obvious, the very fact that the theory was introduced to explain. It predicts that the clock will stop if you touch it, but we already know that. So our understanding is not increased, and the demon theory is untestable.

When you're trying to decide between two theories, can you just rely on evidence alone to determine which theory is better?

The amount or degree of evidence that a theory has is indeed a crucial factor but it cannot be the sole criterion by which we assess explanations. -throughout the history of science, major theories have never been established by empirical evidence alone -there are reasonable criteria and reliable procedures for judging the merits of eligible theories and for arriving at a defensible judgement of which theory is the best

The criterion of simplicity has often been a major factor in the acceptance or rejection of important theories. For example, simplicity is an important advantage that the theory of evolution has over creationism, the theory that the world was created by a divine being. Creationism must assume the existence of a creator and the existence of unknown forces used by the creator. But evolution doesn't make either of these assumptions. Likewise, we accept Copernicus's theory of planetary motion over Ptolemy's b/c the former was simpler. In order to account for irregularities in the movement of certain planets, Ptolemy's theory had to assume that planets have extremely complex orbits (orbits within orbits). Copernicus's theory, however, had no need for so much extra baggage. His theory could account for the observational data without so many orbits within orbits.

The evaluation of a particular theory is not complete until alternative, or competing, theories are considered. There is an indefinite number of theories that could be offered to explain a given set of data. The main challenge is to give a fair assessment of the relevant theories in relation to each other. To fail to somehow address the alternatives is to overlook or deny the relevant evidence, to risk biased conclusion and to court error. Such error/failure is probably the most common error in the appraisal of theories.

The fact that there are BEST explanations implies that not all explanations for a state of affairs are created equal; some are better than others. Just b/c you've devised an explanation for something doesn't mean that you're justified in believing that explanation is the right one. If other explanations are just as good, your explanation is in doubt. If other explanations are better than yours, your not justified in believing it.

The following is an example of a case in which we use inference to the best explanation (often unknowingly): If we wake up and see that the streets outside are wet, we may immediately posit that it's been raining. Without much thinking about it, we may also quickly consider whether a better explanation is that a streetsweeper machine has wet the streets. Just as quickly, we may dismiss this explanation b/c we see that the houses and cars are also wet. After reasoning in this fashion, we may decide to carry an umbrella that day.

True or false. Other things being equal, fruitful theories are superiors to those that aren't fruitful. Fruitful theories are testable and then some. They not only predict something, but they predict something that no one expected.

True

The following is an example of a case in which we use inference to the best explanation: You discover that your care won't start in the morning (the phenomenon to be explained). You would like to know why it won't start (the explanation for the failure) b/c you can't repair the car unless you know what the problem is. You propose possible explanations/theories: the battery is dead, fuel tank is empty, starter has malfunctioned, a vandal has sabotages the car, and all or several of the above. So you try to figure out which theory is the most plausible. You see right away that there is snow around the car from yesterday's snowstorm but there are no tracks and no signs of tampering anywhere. So you dismiss the 4th theory. You remember you filled up the gas tank yesterday and the fuel gauge says full and there's no sign of leakage. So you ignore theory 2. You notice that the lights, heaters and radio work fine and the battery gauge indicates a fully charged batter so you discard the first theory. When you try to start the car, you hear a clicking sound like the one you head when the starter had previously failed. Among the theories you started with, theory 3 now seems the most plausible. This means theory can't be correct because it entails 2 or more theories.

The following is an example of a case in which we use inference to the best explanation: You discover that your care won't start in the morning (the phenomenon to be explained). You would like to know why it won't start (the explanation for the failure) b/c you can't repair the car unless you know what the problem is. You propose possible explanations/theories: the battery is dead, fuel tank is empty, starter has malfunctioned, a vandal has sabotages the car, and all or several of the above. So you try to figure out which theory is the most plausible. You see right away that there is snow around the car from yesterday's snowstorm but there are no tracks and no signs of tampering anywhere. So you dismiss the 4th theory. You remember you filled up the gas tank yesterday and the fuel gauge says full and there's no sign of leakage. So you ignore theory 2. You notice that the lights, heaters and radio work fine and the battery gauge indicates a fully charged batter so you discard the first theory. When you try to start the car, you hear a clicking sound like the one you head when the starter had previously failed. Among the theories you started with, theory 3 now seems the most plausible. This means theory 5 can't be correct because it entails 2 or more theories.

What is the minimum requirement of consistency?

The minimum requirement of consistency is the criterion that any theory worth considering must have both internal and external consistency--that is, be free of contradictions and be consistent with the data the theory is supposed to explain. -a theory that does not meet this minimum requirement is worthless, so there's no need to use the special criteria to evaluate the theory -a theory that meets the requirement is eligible for further consideration

True or False. A theory's strangeness is no good reason to discount it. It is implausible that every theory is equally correct

True

True or False. An antecedently implausible theory might nonetheless turn out to be true or most probable (''best'')

True

True or False. An untestable theory will be unfruitful and also lack explanatory scope.

True

True or False. Applying the criteria of adequacy to a set of theories constitutes the ultimate test of a theory's values, for the best theory is the eligible theory that meets the criteria of adequacy better than any of its competitors.

True

True or False. Despite the lack of formula in theory assessment, the process is far from subjective or arbitrary, There are many distinctions that we successfully make everyday that are not quantifiable or formulaic but they are still objective. We cannot say exactly when day turns into night, when a person with a full head of hair becomes bald, or when a puddle in the rain becomes a pond, but our distinctions between night and day or boldness or hirsuteness or puddles and ponds are clearly objective. Of course, there are cases that aren't so clear cut that give rise to reasonable disagreement among reasonable ppl. But there are also many instances that are manifestly unambiguous. Pretending that these state of affairs are unclear would be irrational. It would simply be incorrect to believe that broad daylight is nighttime or that a puddle is a pond.

True

True or False. Other things being equal, the greater the explanatory scope of a hypothesis, the greater its explanatory power.

True

True or False. Other things being equal, the simpler the hypothesis, the more likely it is to be true and so the greater its prior or antecedent probability.

True

True or False. Other things equal, the more fruitful a hypothesis, the greater its explanatory power.

True

True or False. Sometimes a theory's lack of simplicity is the result of constructing ad hoc hypothesis. If a theory is in trouble b/c it's not matching up with the observational data of the phenomenon, you might be able to rescue it by altering it--by posting additional entities or properties that can account for the data. Such tinkering is legitimate if there is an independent way of confirming the existence of these proposed entities/properties. If there's no way to verify their existence, the modifications are ad hoc hypothesis. Ad hoc hypothesis always make a theory less simple and therefore less credible.

True

True or False. Testable doesn't necessarily mean true and untestable doesn't necessarily mean false.

True

True or False. There is no strict formula or protocol for applying the criteria of adequacy. In deductive arguments, there are rules of inference that are precise and invariable. But inference to the best explanation is a different animal. There are no precise rules for applying the criteria, no way to quantify how a theory measures up according to each criterion, & no way to rank each criterion according to its importance. Sometimes we may assign more weight to the criterion of scope if the theory in question seems comparable to other theories in terms of all the remaining criteria. Other times we may weight simplicity more when considering theories that seem equally conservative or fruitful. The process of theory evaluation is not like solving a math problem--but more like diagnosing an illness or making a judicial decision. It is rational but not formulaic, and it depends on the dynamic of human judgement. The best we can do is follow some guidelines for evaluating theories generally and for applying the criteria of adequacy. Fortunately, this kind of help is usually all we need.

True

True or False. To be worthy of consideration, a theory must meet the minimum requirement for consistency.

True

True or False. We are naturally reluctant to accept explanations that conflict with what we already know and we should be. Accepting beliefs that fly in the face of our knowledge has several risks.

True

We use inference to the best explanation all the time. Often when we try to understand something in the world, we construct explanations for why this something is the way it is, and we try to determine which of these is the best. Devising explanations helps increase our understanding by fitting our experiences and background knowledge into a coherent patter. At every turn, we're confronted with phenomena that we can only fully understand by explaining them. Sometimes we're barely aware that were are using inference to the best explanation.

When comparing two theories to each other, we can say that the final probability of H1 is greater than that of H2 if and only if H1 has the greater OVERALL BALANCE of prior probability and explanatory power.

What is the TEST formula? What four steps does it comprise?

a 4-step procedure for evaluating the worth of a theory -step 1: state the theory and check for consistency -step 2: assess the evidence for the theory -step 3: scrutinize alternative theories -step 4: test the theories with the criteria of adequacy

What is the criterion of testability?

a criterion of adequacy for judging the worth of theories. A testable theory is one in which there's some way to determine whether the theory is true or false--that is, it predicts something other than what it was introduce to explain. -other things being equal, testable theories are superior to untestable ones; they may be able to increase our understanding of a phenomenon. But an untestable theory is just an oddity. -OTHER THINGS EQUAL, THE MORE TESTABLE A THEORY, THE GREATER ITS EXPLANATORY POWER.

What is the criterion of scope?

a criterion of adequacy for judging the worth of theories. A theory with scope is one that explains or predicts phenomena other than that which it was introduced to explain -a theory that does not have much scope is one that explains very little--perhaps only the phenomenon it was introduced to explain and not much else. -the more a theory explains or predicts, the more it extends our understanding and the less likely it is to be false b/c it has more evidence in its favor. -other things being equal, the best theory is the one with the greatest scope. THE GREATER THE SCOPE OF A HYPOTHESIS, THE GREATER ITS EXPLANATORY POWER. And if other things are't equal, a theory with superior scope doesn't necessarily win the day b/c it may do poorly on the other criteria, or another theory might do better.

What is an ad hoc hypothesis?

a hypothesis, or theory, that cannot be verified independently of the phenomenon it's supposed to explain. Ad hoc hypothesis always make a theory less simple and therefore less credible.

explanation

a statement (or statements) asserting why or how something is the case -intended to clarify, elucidate & increase our understanding

What does it mean to say that a theory does not have much scope?

a theory that doesn't have much scope is one that explains very little--perhaps only the phenomena it was introduced to explain and not much else

external consistency

a theory that is externally consistent is consistent with the data it's supposed to explain--it fully accounts for the phenomenon to be explained.

internal consistency

a theory that is internally consistent is consistent with itself, meaning that it is free of contractions.

What is the following the basic form of? H1 has the greatest overall balance of prior probability and explanatory power compared to rival hypothesis H2...Hn. (those hypothesis are exclusive and exhaustive) (probably) H1 is true (not merely the ''best'')

abductive reasoning=arguments to the best explanation

an attempt to rescue a theory from evidence that goes against it by coming up with excuses (''I'm not feeling strong today'') -if you keep coming up with such explanations, then you cannot test it. If you cannot test it, then it has lower explanatory power. (Note: this doesn't necessarily mean that it's false)

ad hoc explanation/hypothesis

What is a theoretical explanation?

an explanation that serves as a theory, or hypothesis, that tries to explain why something is the way it is, why something is the case or why something happened -in this category we must include all explanations intended to explain the cause of events--the causal explanations that are so important to daily life -theoretical explanations are, of course, claims. They assert that something is or is not the case. -they are the heart of inference to the best explanation

What is a procedural explanation?

an explanation that tries to explain how something is done or how an action is carried out

our stock of encyclopedic knowledge, i.e., well-confirmed beliefs, such as we have in textbooks or encyclopedias.

background knowledge (B)

how much a theory claims/says -the more a theory says, the less plausible the hypothesis -the less a theory says, the more plausible the hypothesis

modesty

If you're friend says that dogs lay eggs just as chickens do, you'd probably reject the claim about egg-laying dogs b/c it fails the criteria of ____. That is, we would reject the canine-egg theory b/c among other things, it conflicts with our well founded beliefs about mammals, evolution, canine anatomy, and much more. Humans have an enormous amount of experience with dogs and none of it suggest that dogs can lay eggs. In fact, a great deal of what we know about dogs suggests that they cannot lay eggs. To accept the canine-egg theory despite its conflicting with a mountain of solid evidence would be irrational and destructive of whatever understanding we had of the subject

conservatism

how well a theory fits with existing knowledge

conservatism

the degree to which a hypothesis fits with the background information (particularly with well-confirmed theories and models) -other things being equal, the greater the degree to which the hypothesis accords with previously acquired information, the more likely it is to be true (the greater its prior or antecedent probability.

conservatism

the degree to which the theory fits with our background information B

conservatism

Which criteria pertain to prior probability (plausibility) of a theory?

conservatism simplicity modesty

the evidence or puzzling facts that need to be explained by theories

evidence (E) -we can also use F for facts or O for observations

explanatory power

explanatory power or likelihood of a theory is the probability of the evidence E ''given'' the hypothesis H: P(E/H). Or it can also be written as P (E/B&H) -this is not the same as the final probability of H: P (H/E) -that is, how well does the theory explain the evidence; to what degree does the theory make the evidence probable. -this is just in relation to E

the number and variety of facts that a hypothesis explains, i.e., makes more or less likely, and the degree to which it makes them likely.

explanatory scope

Which criteria pertain to explanatory power (liklihood) of a theory?

explanatory scope testability fruitfulness

-the degree to which a hypothesis has novel and daring observational consequences--typically in the form of predictions--that its competitors do not have and that are verified to be true. (____is testability and then some) -The observational consequences may be entailed by the hypothesis (often with the aid of previously well-established auxiliary assumptions) or made probable to some degree by it.

fruitfulness

predictions that the theory makes that are novel, ''risky'', and true

fruitfulness

the number of novel predictions made

fruitfulness

What is the following an example of? The best explanation for Maria's absence today is that she's angry at the boss. Yep, she's mad at the boss.

inference to the best explanation

What is the following an example of? The defendant's footprints were all over the crime scene, the police found the victim's blood on his shirt, and he was in possession of the murder weapon. The only explanation for all this that makes any sense is that the defendant actually committed the crime. He's guilty

inference to the best explanation

What is the following an example of? The newest quarterback dropped the ball again. The best explanation for that screw up is that he's nervous. So he's definitely nervous

inference to the best explanation

arguments that try to show that one hypothesis is better than the others -these arguments are strong if they take into consideration the 2 factors that influence abductive strength (prior probability & explanatory power)

inference to the best explanation

What are the following an example of? -This word means ''dashing'' or ''jaunty'' -When Mary smiled, she was signaling her agreement -''Effect'' means to accomplish but ''affect'' means to influence

interpretive explanations

(roughly) a measure of the content of the hypothesis, i.e., how much it says, -other things equal the less the hypothesis says, the more likely it is to be true and so the greater its antecedent probability.

modesty

What is the ''best'' theory?

the ''best'' theory has the highest final probability of the theories considered, meaning that it has the greatest overall balance of prior probability and explanatory power, but it is not necessarily true -it's always possible for the conclusions of non-deductive arguments to be false.. Also, the best theory might have a final probability of less than 0.5 -However, if our set of theories is a mutually exclusive and jointly exhaustive set, then they will have prior probabilities that add up to 1.0. In this case, the ''best'' theory will have a final probability of greater than 0.5. This is why it's important for a detective to consider a complete set of theories that does not leave out any reasonable hypothesis.

What does it mean for a theory to be the best?

the best theory is the eligible theory that meets the criteria of adequacy better than any of its competitors (Note: eligible means that the theory has already met the minimum requirements for consistency)

What are the 2 factors that influence the abductive strength of abductive arguments?

the prior probabilities of the theories the explanatory power of the theories

What are the criteria of adequacy?

the standards used to judge the worth of explanatory theories -they include testability, fruitfulness, scope, simplicity, and conservatism, && modesty -they're essential tools of science and have been used by scientists throughout history to uncover the best explanation for all sorts of events/states of affairs -also useful and used among non-scientists. -we use the criteria of adequacy to judge the plausibility of a theory in relation to competing theories. The best theory is the one that meets the criteria of adequacy better than of its competitors.

What is a teleological explanation?

tries to explain the purpose of something, how it functions, or how it fits into a plan

What is the difference between an explanation and argument?

while an explanation tells us why or how something is the case, an argument gives use reason for believing that something is the case

CH 9 (Inference to the Best Explanation)

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