The Logical Leap: Induction in Physics


Recommended Posts

Suppose I claim that no human being can fly by merely flapping his or her arms with no artificial aids. How did I arrive at this generalization? By inductive reasoning, clearly, but this was not what logicians call "complete" (or "perfect") induction. That is to say, I did not observe every human being who has ever existed. Nor, even if I had, could I possibly observe every human being who will exist in the future.

My generalization rests upon "incomplete" (or what Aristotle called "material") induction. This is essentially a process of reasoning from particulars to universals. I know of my own inability to fly, and I know from my knowledge of other people that they cannot fly either. This is a very incomplete enumeration, of course. There are many billions of people that I know nothing about, so how can I generalize about them?

As your subsequent reasoning shows, you aren't arriving at your generalization by "a process of reasoning from particulars to universals" -- i.e., by reasoning from "Some a are X" to "All a are X."

There are different type of inductive reasoning, and my example illustrates one that has often been discussed, e.g., by both Aristotle and Popper.

Instead you primarily (although not entirely) reason on the basis of an at least implicit theory of physics according to which humans flying by flapping their arms is impossible:

In my example, you don't need a "theory" of why humans cannot fly by flapping their arms. You need only know that you cannot do it, you have never seen anyone do it, and that the physical attributes of humans are similar enough to conclude that no human being can do it. You have seen people with thin arms and highly muscular arms, and these variations make not the least bit of difference.

Ghs: My generalization is based on my knowledge that human beings have roughly similar physical attributes, and I know that our physical attributes determine our physical powers . And I simply cannot conceive of human arms that would enable a person to fly. [....]

[....]

In truth, we would never reach the point of testing my generalization in any fashion, because we regard its contradictory that some humans (i.e., at least one) can fly by flapping their arms as impossible and therefore as utterly lacking in credibility. And we can legitimately say this -- with certainty -- even if we don't have the necessary scientific knowledge to explain why humans cannot fly in this manner. My generalization is the result of inductive reasoning.

The generalization isn't the result of inductive reasoning in the meaning of "inductive reasoning" which you gave, to repeat, "a process of reasoning from particulars to universals."

I did reason from particulars to a universal statement, i.e., that no human being can fly by flapping his arms. But I didn't do so by running up a count on the number of particulars. Rather, I assessed the attributes of human beings and their corresponding powers. I extrapolated from a limited number of observations the relevant characteristics of humans that make them unable to fly.

It's this meaning -- reasoning from "Some a are X" to "All a are X" -- which I think was Popper's meaning of "induction" when he said that inductive reasoning is invalid.

Your observation is as old as the hills; if this is all that Popper meant, he would have merely been repeating a truism for the umpteenth time.. Even Aristotle accepted it -- he claimed that only complete enumeration could justify this kind of induction -- and this later led anti-Aristotelians, such as Francis Bacon, to show how induction plays a crucial role in science. The Scientific Revolution was in part a reaction against the Aristotelian deductive method that had dominated western thinking for centuries, in favor of induction.

But Aristotle was also concerned with how we can justify the major premise of a deductive syllogism, e.g., "All men are mortal" -- followed by, "Socrates is a man, therefore Socrates is mortal." As I recall, Aristotle doesn't call this process "induction" -- I think he calls it "dialectics" -- but Popper and many others have correctly treated it as a type of inductive reasoning. And Popper rejects it entirely in his criticism of "essentialism." This is what Popper has in mind when he rejects the "intuitive" method of Aristotle.

In its original form, roughly put, this approach claims that if we can ascertain the "essence" of a thing, i.e., those characteristics that make it the kind of thing it is, then we don't need to examine every instance of that thing in order to generalize. Indeed, we may be able to generalize on the basis of one instance, in some cases. We reason, in effect, as follows: If x is the same kind of thing as y -- i.e., if both things have the same properties -- then both things will have the same capacities and powers. (Instead of "same," we could say "relevantly similar.")

Of course, since Popper rejects metaphysical essences, he does not regard this approach as valid. But one needn't believe in essences to defend the overall approach. One can argue in the same way from any characteristic, so long as that characteristic is relevant to the generalization.

Returning to our example of Socrates: Against the deductive syllogism it was commonly argued that the reasoning is circular. For if we know that all men are mortal, then we already know that Socrates is mortal, so the conclusion tells us nothing that was not already contained in the premises.

Although this objection has had its share of critics, it is true that the conclusion of a deductive syllogism does not tell us anything that was not already implicitly contained in the premises. Even ardent defenders of the syllogism have said that it only makes the implicit explicit. So how can we know that all men are mortal? -- the major premise. Must we know every instance subsumed in the class of "man"? If so, then this complete enumeration will tell us that Socrates is mortal, and the syllogism is unnecessary. But a complete enumeration is clearly impossible, for how do we know that some people now living may not live forever?

This is where we rely on the kind of induction that I have employed. From a limited number of observations, we know that the human body grows old and dies. We may not know why, so we may not have a theory that explains why men are mortal, but we know enough from our experiences with our own bodies (aging, etc.) and the bodies of other people to generalize that any beings with the same characteristics will also die.

Note that this reasoning (which I have outlined in a very rough manner) leads to a conclusion that does not increase in probability or grow more certain as we observe more instances (past a certain point, at least.) It does not say, "I knew of 1000 people who have died, but I now know of 1001, so I am even more certain that all men are mortal." That's not the way this reasoning, which we use in countless ways in everyday life, works. Rather, we reason from a limited number of instances to the relevant characteristics, and it is from our assessment these common characteristics (e.g., their causal implications) that we generalize.

If you look at almost any book on logic that treats inductions sympathetically, you will find the argument that induction and deduction, though different, are not opposed to one another. They are complementary. Indeed, the kind of reasoning I have described can be formulated in a syllogism, though it requires a hypothetical, if-then, structure.

Is this kind of reasoning always sound? No, of course not. People can make a lot of mistakes, but these usually stem not from the reasoning itself but from a misidentification of x or y, i.e., an erroneous belief that x and y are similar in every relevant respect.

Further, as I recall, by "invalid" he meant in the formal logic sense wherein a "valid" argument means an argument in which the truth of the premises would guarantee the truth of the conclusions. ("Some a are X" doesn't guarantee the truth of the conclusion "All a are X.")

Popper's objection is far stronger than this. He doesn't believe that induction of any kind can provide even the lowest level of probability.

I wrote this very quickly. It is not as coherent as I would like, but it's the best I can do for now.

Ghs

Link to comment
Share on other sites

  • Replies 1.4k
  • Created
  • Last Reply

Top Posters In This Topic

Early this morning I watched a rerun of "Married With Children." Al Bundy, a shoe salesman, had been goofing off at work, and the owner finally confronted him. She said it was evident that he wasn't doing his job. When Al asked her how she knew this, she said, "Sales have dropped 500 percent during the last year. How do you explain this?"

Al replied, "Women are walking less?"

It struck me that Al's "conjecture" has a number of Popperian implications. The owner dismissed Al's theory out of hand, but I don't see how she could have done this if she had been a strict Popperian. Al's conjectural theory would explain the problem under consideration, and, if I understand Popper correctly, any such theory is neither more nor less probable than any other theory.

We therefore have two theories of equal(initial) merit that explain the 500 percent drop in sales. One is that Al has not been doing his job; the other is that women have been walking less. How do we decide between these two "conjectures" with the Popperian method of falsification?

Ghs

Link to comment
Share on other sites

Even if induction is not used in some of the sciences, it is used in archeology, anthropology, and other historical sciences, and it also used in many of the "social sciences." Whether the latter should be called "sciences" or not is irrelevant to Popper's contention, since his objections to induction are universal. Popper's insistence that the physical and social sciences employ the same basic methodology -- a position known as "methodological monism," in contrast to the "methodological dualism" of Hayek, Mises, and others in the Verstehen tradition -- is as wrong as it could be.

George, could you explain further methodological monism versus dualism and your reaction? I would describe the methodology of comparative linguists as identical to that of the hard sciences, especially palaeontology.

Link to comment
Share on other sites

Even if induction is not used in some of the sciences, it is used in archeology, anthropology, and other historical sciences, and it also used in many of the "social sciences." Whether the latter should be called "sciences" or not is irrelevant to Popper's contention, since his objections to induction are universal. Popper's insistence that the physical and social sciences employ the same basic methodology -- a position known as "methodological monism," in contrast to the "methodological dualism" of Hayek, Mises, and others in the Verstehen tradition -- is as wrong as it could be.

George, could you explain further methodological monism versus dualism and your reaction? I would describe the methodology of comparative linguists as identical to that of the hard sciences, especially palaeontology.

I know virtually nothing about comparative linguistics, so I cannot speak to that issue.

This is a very complicated area, one that requires some historical background to appreciate. I don't really have the time now to get into this in detail, but I did have a lot on methodology in my never-to-be finished manuscript, The Disciplines of Liberty. Unfortunately it is spread throughout nearly 400 pages. The following excerpt (minus endnotes and italics) leaves a lot out that is explained elsewhere, but it may give you some idea. This is an uncorrected preliminary draft.

III

A Unity of Method?

How do the human sciences differ from the natural sciences? Even if we grant that the study of human action differs significantly from the study of physical nature, does this necessitate a radical difference of method between the human sciences and the natural sciences? This question, which has been debated for many decades, is of fundamental importance for the methodology of the human sciences. Attempts to answer it generally fall into one of two categories, which I shall call monism and dualism .

Methodological monism, which is affiliated with a doctrine known as “the unity of science,” maintains that the scientific method is (or should be) essentially the same in both the natural and the human sciences. Methodological dualism, in contrast, maintains that there exists (or should exist) a radical difference of method between these two fields of study. Human action, according to dualism, has a subjective meaning for the acting agent, and this unique feature of human action, which is not exhibited by atoms, molecules, and other non-human entities, imposes upon the human sciences a distinctive method of inquiry that we do not find in the natural sciences. The human sciences are necessarily “subjective” in the sense that they must take into account the inner meaning of actions, as those actions are understood by the people who take them. The sociologist Alfred Schutz explained some implications of dualism as follows::

[T]here is an essential difference in the structure of the thought objects or mental constructs formed by the social sciences and those formed by the natural sciences. It is up to the natural scientist and to him alone to define, in accordance with the procedural rules of his science, his observational field, and to determine the facts, data, and events within it which are relevant for his problem or scientific purpose at hand. Neither are those facts and events pre-selected, nor is the observational field pre-interpreted. The world of nature, as explored by the natural scientist, does not ‘mean’ anything to the molecules, atoms, and electrons therein. The observational field of the social scientist, however, namely the social reality, has a specific meaning and relevance structure for the human beings living, acting, and thinking therein. By a series of common-sense constructs they have pre-selected and pre-interpreted this world which they experience as the reality of their daily lives. It is these thought objects of theirs which determine their behavior by motivating it. The thought objects constructed by the social scientist, in order to grasp this social reality, have to be founded upon the thought objects constructed by the common-sense thinking of men, living their daily lives within their social world. Thus, the construct of the social sciences are, so to speak, constructs of the second degree, namely constructs of the constructs made by the actors on the social scene, whose behavior the social scientist has to observe and to explain in accordance with the procedural rules of his science.

This stress on the subjective meaning and significance of human action (known as “the interpretive method”) was defended by Max Weber, Georg Simmel, and other members of the “German School” of sociology. It has also played a key role in the methodological arguments of “Austrian” economists, such as F.A. Hayek and Ludwig von Mises. All such theorists have defended methodological dualism in one form or another; but before examining their position in greater detail, we should clarify what is (and is not) at stake in the ongoing debate between monism and dualism.

A good deal of confusion has been caused in this ongoing debate by a failure to distinguish between epistemology and methodology. Epistemology is concerned with the fundamental features of human knowledge – with the nature of concepts and propositions, for example, and with the meaning of truth. This discipline is more fundamental than methodology, which investigates how epistemological criteria should be applied to a particular field of study.

Insufficient appreciation of this distinction has led to considerable confusion in the debate between monism and dualism. Epistemology and methodology pertain to different levels of analysis, so an epistemological monist can also be a methodological dualist. The methodological dualist needn’t uphold a similar dualism in the realm of epistemology; he needn’t argue that our knowledge of human action, qua knowledge, differs fundamentally from our knowledge of physical nature or that it should be tested by different epistemological procedures. He may argue instead that the human and natural sciences, while operating from the same epistemological foundation, require different applications of the same epistemological concepts and criteria to their respective disciplines, owing to the essential differences between human and non-human phenomena.

This is a complex issue, so an illustration may help to clarify the point. In his argument for a “unity of method” in the natural and human sciences, Karl Popper cites Carl Menger as a fellow opponent of methodological dualism. This is an intriguing claim, because it attributes to Menger, the revered father of Austrian economics, a position that differs radically from that of later Austrians, such as Hayek and Mises. If Popper is right, if Menger was indeed a methodological monist, this would mean one of two things: either modern Austrians have failed to understand Menger or, having understood him, they have repudiated a basic component of his methodology.

Contrary to Popper, however, Menger was neither a methodological monist nor an opponent of dualism. If Popper failed to understand Menger, this is largely because he failed to differentiate Menger’s general epistemology from his views on methodology. Menger was at once an epistemological monist and a methodological dualist. The former position is contained in Menger’s discussion of the conceptual methods that every science must employ when formulating general laws. From this epistemological standpoint, “no essential difference between the [human] and the natural sciences exists, but at most only one of degree.” Menger’s “empirical method,” which he applies to every kind of science, both natural and human, is based on his theory of concepts and general propositions. It is an epistemological principle, not a methodological one; and its specific application will vary according to the cognitive demands of a particular science. Thus does Menger categorically reject Popper’s “unity of method”:

[E]very method of investigation acquires its own specific character from the nature of the field of knowledge to which it is applied. It would be improper, accordingly, to attempt a natural-scientific orientation of our science [of economics]. Past attempts to carry over the peculiarities of the natural-scientific method of investigation uncritically into economics have led to most serious methodological errors….

It would be difficult to find a more concise statement of the difference between epistemology and method. The method appropriate to a particular science is determined, not by its general epistemological principles (which apply to every science), but by the proper application of those principles to the “field of knowledge,” or subject-matter, of a particular science. This, according to Menger, is true empiricism – not the uncritical application of a universal method to every science, but the careful adaptation of method to subject matter, as means to the cognitive end of knowledge.

The distinction between methodological monism and dualism has often been discussed by social theorists, so you should be able to find more info on the Net.

Ghs

Link to comment
Share on other sites

In my example, you don't need a "theory" of why humans cannot fly by flapping their arms. You need only know that you cannot do it, you have never seen anyone do it, and that the physical attributes of humans are similar enough to conclude that no human being can do it. You have seen people with thin arms and highly muscular arms, and these variations make not the least bit of difference.

I did reason from particulars to a universal statement, i.e., that no human being can fly by flapping his arms. But I didn't do so by running up a count on the number of particulars. Rather, I assessed the attributes of human beings and their corresponding powers. I extrapolated from a limited number of observations the relevant characteristics of humans that make them unable to fly.

I agree with Ellen, that a theory of some sort is implied. If not, then the only reason you have for your belief that humans cannot fly is that you have never seen one fly. If I ask you "why not?", you will have to come up with some "theory" about why this is the case. I believe the theory is hidden in this phrase "assessed the attributes of human beings and their corresponding powers".

Link to comment
Share on other sites

In my example, you don't need a "theory" of why humans cannot fly by flapping their arms. You need only know that you cannot do it, you have never seen anyone do it, and that the physical attributes of humans are similar enough to conclude that no human being can do it. You have seen people with thin arms and highly muscular arms, and these variations make not the least bit of difference.

I did reason from particulars to a universal statement, i.e., that no human being can fly by flapping his arms. But I didn't do so by running up a count on the number of particulars. Rather, I assessed the attributes of human beings and their corresponding powers. I extrapolated from a limited number of observations the relevant characteristics of humans that make them unable to fly.

I agree with Ellen, that a theory of some sort is implied. If not, then the only reason you have for your belief that humans cannot fly is that you have never seen one fly. If I ask you "why not?", you will have to come up with some "theory" about why this is the case. I believe the theory is hidden in this phrase "assessed the attributes of human beings and their corresponding powers".

Yes, there is a theory involved, but it is not a theory of physics, not even an implicit one. Rather, it is a philosophical theory of causation. As H.W.B. Joseph says in his discussion of induction ("Presuppositions of Induction," An Introduction to Logic, 2nd ed., Oxford, pp. 408-09):

[T]he causal relation has nothing to do with the number of instances, so far as its existence -- though much so far as it detection --is concerned; it is bound up altogether with the nature or character of things, and the nature of anything is not a question of the number of things that may be or have been fashioned. Yet if a thing is to have any determinate nature and character at all, there must be uniformity of action in different things of that character, or of the same thing on different like occasions. If a thing a under conditions c produces a change x in a subject s -- if, for example, light of certain wave-lengths, passing through the lens of a camera, produces a certain chemical change (which we call the taking of a photograph of Mount Everest) upon a photographic film -- the way in which it acts must be regarded as a partial expression of what it is. It could only act differently if it were different. As long therefore as it is a, and stands related under conditions c to a subject that is s, no other effect than x can be produced; and to say that the same thing acting on the same thing under the same conditions may yet produce a different effect, is to say that a thing need not be what it is.

Thus the theory involved in my example is not a theory of why humans cannot fly by flapping their arms. Rather, it is the theory that entities with the same relevant attributes will have the same capacities and powers, and therefore will (or will not) be able to do the same things.

Ghs

Link to comment
Share on other sites

People can have many reasons about why they believe something is possible, which is why you can't falsify a positive assertion. You may not like or agree with their reasons but that is not the point.

A positive assertion can be falsified. If for example person P says of person Q that Q strictly adheres to the law and it turns out Q did things which are illegal, P's positive assertion has been falsified.

The Creationists' positive assertions about how Adam and Eve were created by god can be falsified by the facts acquired through biological research.

The same applies to the existence of God. I can say God doesn't exist with certainty because to disprove me you have to produce God in a way I can see.

To quote George H: Smith from Why Atheism, p. 21: "Failure to prove the positive does not establish the negative". (Ghs)

Fancy two fish living on the dark seaground who can think and speak. Can fish A say "with certainty" that a sky does not exist just because fish B (who believes there might be something like a sky) is unable to produce evidence?

Or an example from real life: suppose John has committed a crime but left no evidence behind which would link him to the deed.

Now to say "with certainty" that John is not the perp merely on the grounds that there is no evidence avaiable implicating him would be false.

On the other hand if you say God exists and you have seen him I can't deny that because I can't be in your head.

The burden of proof falls on the one who affirms the truth of a proposition, such as "God exists". (George H. Smith, WA, p. 31.)

Since an individual who claims that God exists and that he/she has seen him can't offer proof, the statement "God exists" qualifies as mere belief, and this type of belief can indeed neither be falsified nor verified.

Which is why deriving from a mere (and unverifyable) belief claims as to what this being wants from us in the form of "god's will" can be rejected on epistemological grounds alone.

Early this morning I watched a rerun of "Married With Children." Al Bundy, a shoe salesman, had been goofing off at work, and the owner finally confronted him. She said it was evident that he wasn't doing his job. When Al asked her how she knew this, she said, "Sales have dropped 500 percent during the last year. How do you explain this?"

Al replied, "Women are walking less?"

It struck me that Al's "conjecture" has a number of Popperian implications. The owner dismissed Al's theory out of hand, but I don't see how she could have done this if she had been a strict Popperian. Al's conjectural theory would explain the problem under consideration, and, if I understand Popper correctly, any such theory is neither more nor less probable than any other theory.

We therefore have two theories of equal(initial) merit that explain the 500 percent drop in sales. One is that Al has not been doing his job; the other is that women have been walking less. How do we decide between these two "conjectures" with the Popperian method of falsification?

On what grounds do you call Al's ironic question "Women are walking less?" a theory?

Edited by Xray
Link to comment
Share on other sites

Early this morning I watched a rerun of "Married With Children." Al Bundy, a shoe salesman, had been goofing off at work, and the owner finally confronted him. She said it was evident that he wasn't doing his job. When Al asked her how she knew this, she said, "Sales have dropped 500 percent during the last year. How do you explain this?"

Al replied, "Women are walking less?"

It struck me that Al's "conjecture" has a number of Popperian implications. The owner dismissed Al's theory out of hand, but I don't see how she could have done this if she had been a strict Popperian. Al's conjectural theory would explain the problem under consideration, and, if I understand Popper correctly, any such theory is neither more nor less probable than any other theory.

We therefore have two theories of equal(initial) merit that explain the 500 percent drop in sales. One is that Al has not been doing his job; the other is that women have been walking less. How do we decide between these two "conjectures" with the Popperian method of falsification?

On what grounds do you call Al's ironic question "Women are walking less?" a theory?

"Hypothesis" (i.e., a possible but unproven explanation) might have been a better choice of words.

Ghs

Link to comment
Share on other sites

Thus the theory involved in my example is not a theory of why humans cannot fly by flapping their arms. Rather, it is the theory that entities with the same relevant attributes will have the same capacities and powers, and therefore will (or will not) be able to do the same things.

But these "relevant attributes and powers" are what? In order to explain what you mean you will necessarily be moving towards a physical explanation, ie. physics. Even if it something as simple as "humans cannot generate enough lift with their arms because they lack the wing structure that birds have".

Link to comment
Share on other sites

A positive assertion can be falsified. If for example person P says of person Q that Q strictly adheres to the law and it turns out Q did things which are illegal, P's positive assertion has been falsified.

The Creationists' positive assertions about how Adam and Eve were created by god can be falsified by the facts acquired through biological research.

Whether or not someone broke the law is decided by other people and so is a matter of opinion. Also, nothing in biological research can falsify that Adam and Eve were created - it only makes it highly unlikely. If I said God exists but he only allows certain people to see him (like me :) then how can you falsify that?

Link to comment
Share on other sites

A positive assertion can be falsified. If for example person P says of person Q that Q strictly adheres to the law and it turns out Q did things which are illegal, P's positive assertion has been falsified.

The Creationists' positive assertions about how Adam and Eve were created by god can be falsified by the facts acquired through biological research.

Whether or not someone broke the law is decided by other people and so is a matter of opinion. Also, nothing in biological research can falsify that Adam and Eve were created - it only makes it highly unlikely. If I said God exists but he only allows certain people to see him (like me :) then how can you falsify that?

I thought the basic idea is that if it cannot be falsified it is effectively false, axioms aside, but this is epistemological and only addresses the limitations of knowledge. Someday someone may adduce actual evidence for the existence of God. When I say "God is existence" I am merely making an axiomatic statement or a more complicated variation on "A is A."

--Brant

Link to comment
Share on other sites

Thus the theory involved in my example is not a theory of why humans cannot fly by flapping their arms. Rather, it is the theory that entities with the same relevant attributes will have the same capacities and powers, and therefore will (or will not) be able to do the same things.

But these "relevant attributes and powers" are what? In order to explain what you mean you will necessarily be moving towards a physical explanation, ie. physics. Even if it something as simple as "humans cannot generate enough lift with their arms because they lack the wing structure that birds have".

I do not understand in the least how digital cameras work. But if from my experience with a limited number of digital cameras, I purchase a like camera, I expect it to work in the same manner; i.e., I expect it take pictures. Why? Because I know that entities with the same characteristics will behave -- or in this case function -- in the same manner. (Knowledge of even one digital camera would be sufficient to draw this conclusion.)

Suppose I purchase a digital camera and it doesn't work. Will I conclude that my earlier inductive generalization was wrong? Will I say to myself, "Well, even if my camera is the same as other digital cameras, I was wrong to conclude that it should take pictures like other cameras, because my reasoning was based on an incomplete enumeration"? No; instead, I would conclude that there is something wrong with my camera, i.e., that it is not the same as functioning cameras in every relevant respect. If someone were to ask me why my camera doesn't work like other cameras, I would have to say, "I don't know."

I can legitimately reason in this manner with no knowledge of how digital cameras work. The same is true of concluding, based on a limited number of observations, that humans cannot fly by flapping their arms. True, a knowledge of why humans cannot fly would add to my knowledge and thereby strengthen my conclusion, but such knowledge is not essential to it.

I agree that my generalization might be "moving towards a physical explanation." But I would be unlikely to search for such an explanation unless I had first concluded that humans cannot fly and then wondered why they cannot fly.

There is some wiggle room here, of course. If by a physical explanation, you mean nothing more than observing, in effect, that the arms of humans are not like the wings of birds, then I suppose you could say that some physical explanation is implicit in my generalization. But I don't consider this an explanation, much less a theory. All it really says is that humans cannot fly because humans are not like birds.

As for the "lift" provided by wings, I doubt if this term would even make sense to a person with no knowledge of aerodynamics -- unless by "lift" you mean nothing more that the ability to "lift" off the ground. Yet such a person could still generalize about humans; indeed, such a person may have never seen a bird. (This final paragraph is off the top of my head; I wouldn't go to the wall to defend it.)

Ghs

Link to comment
Share on other sites

Suppose I purchase a digital camera and it doesn't work. Will I conclude that my earlier inductive generalization was wrong? Will I say to myself, "Well, even if my camera is the same as other digital cameras, I was wrong to conclude that it should take pictures like other cameras, because my reasoning was based on an incomplete enumeration"? No; instead, I would conclude that there is something wrong with my camera, i.e., that it is not the same as functioning cameras in every relevant respect. If someone were to ask me why my camera doesn't work like other cameras, I would have to say, "I don't know."

I don't know if it's "wrong" to make these kind of assumptions but there is always a risk. We are free to make all kinds of assumptions but they are still assumptions and often we are reminded that this is so when things don't work out as we expect. It is precisely when this happens that encourages us to have a closer look and thus our knowledge increases.

Link to comment
Share on other sites

Suppose I purchase a digital camera and it doesn't work. Will I conclude that my earlier inductive generalization was wrong? Will I say to myself, "Well, even if my camera is the same as other digital cameras, I was wrong to conclude that it should take pictures like other cameras, because my reasoning was based on an incomplete enumeration"? No; instead, I would conclude that there is something wrong with my camera, i.e., that it is not the same as functioning cameras in every relevant respect. If someone were to ask me why my camera doesn't work like other cameras, I would have to say, "I don't know."

I don't know if it's "wrong" to make these kind of assumptions but there is always a risk. We are free to make all kinds of assumptions but they are still assumptions and often we are reminded that this is so when things don't work out as we expect. It is precisely when this happens that encourages us to have a closer look and thus our knowledge increases.

My expectation that if one camera takes pictures, then an identical camera should also take pictures is far more than an assumption. The "risk" is not in my reasoning, but in my assumption that any camera I purchase will in fact be identical to other cameras.

Ghs

Link to comment
Share on other sites

My expectation that if one camera takes pictures, then an identical camera should also take pictures is far more than assumption. The "risk" is not in my reasoning, but in my assumption that any camera I purchase will in fact be identical to other cameras.

OK, it's far more than an assumption, what is it then? A very strong assumption? So there is a scale of assumptions going from very weak to very strong? I can live with that. :)

Link to comment
Share on other sites

My expectation that if one camera takes pictures, then an identical camera should also take pictures is far more than assumption. The "risk" is not in my reasoning, but in my assumption that any camera I purchase will in fact be identical to other cameras.

OK, it's far more than an assumption, what is it then? A very strong assumption? So there is a scale of assumptions going from very weak to very strong? I can live with that. :)

If this is an assumption, then all of science rests upon the same assumption. Scientists rely upon instruments, after all, and the "assumption" I made about cameras also applies to those instruments. Unless scientists "assumed" that the same instruments will work in the same way, science would be impossible.

Ghs

Link to comment
Share on other sites

A positive assertion can be falsified. If for example person P says of person Q that Q strictly adheres to the law and it turns out Q did things which are illegal, P's positive assertion has been falsified.

The Creationists' positive assertions about how Adam and Eve were created by god can be falsified by the facts acquired through biological research.

Whether or not someone broke the law is decided by other people and so is a matter of opinion. Also, nothing in biological research can falsify that Adam and Eve were created - it only makes it highly unlikely. If I said God exists but he only allows certain people to see him (like me :) then how can you falsify that?

But the discussion was about whether an assertion can be falsified.

"Assertion" (from Longman's Dictionary): 'Something that you say or write that you strongly believe'.

You said positive assertions can't be falsified.

In my example, person P says of person Q that Q strictly adheres to the law and in case it turns out Q did things which were illegal, P's positive assertion has been falsified. That is, P's strong belief in something related to Q turned out to be false. In the context of this issue, it does not matter who decides whether a law is broken or not.

Another example: "It was Suzie who took the cookies from the jar, you can bet on that, Mom!" Sarah's brother Tom tells their mother. He strongly believes it was Suzie, i. e. makes a positive assertion. In case it turns out the dog took the cookies, Tom's positive assertion has been falsified.

Also, nothing in biological research can falsify that Adam and Eve were created - it only makes it highly unlikely.

The results of biological research exclude the possibility of the female having been created from the male's rib, and the results of geological and astronomical research exclude that the world was created in seven days.

If I said God exists but he only allows certain people to see him (like me :) then how can you falsify that?

I don't know if you have read Ghs's book Why Atheism; it contains a section dealing specifically with this issue. (pages 31 - 34).

Since saying that God exists but only you can see him excludes as irrelevant any appeal to empirical evidence (see Ghs, WA, p. 32), it can't be falsified.

Nor can it be verified and therefore your proposition merely would give the other person information about what you happen to believe.

Brant Gaede When I say "God is existence" I am merely making an axiomatic statement or a more complicated variation on "A is A."

You make a statement about what your idea of a god is. Existence has a god-like status for you. Equating god with existence could also be called a pantheistic position. :)

Edited by Xray
Link to comment
Share on other sites

If this is an assumption, then all of science rests upon the same assumption. Scientists rely upon instruments, after all, and the "assumption" I made about cameras also applies to those instruments. Unless scientists "assumed" that the same instruments will work in the same way, science would be impossible.

I agree, all science relies on assumptions and as science progresses it makes less and simpler assumptions. The behaviour of instruments is not the kind of assumption I am referring to here, however, since it possible to verify if instruments are working properly. I was thinking more like, for example, Newton assumed that space and time were independent and absolute and built a system of dynamics based on that assumption.

Link to comment
Share on other sites

I agree, all science relies on assumptions and as science progresses it makes less and simpler assumptions.

I guess particle smashers are a step backward then?

Link to comment
Share on other sites

I agree, all science relies on assumptions and as science progresses it makes less and simpler assumptions.

I guess particle smashers are a step backward then?

How so?

Ba'al Chatzaf

Link to comment
Share on other sites

In my example, person P says of person Q that Q strictly adheres to the law and in case it turns out Q did things which were illegal, P's positive assertion has been falsified.

Let me rephrase.

One cannot say with certainty what something is but one can say with certainty what something is not. For example, I can say with certainty that the earth is not a sphere but I cannot say exactly what shape it is.

Link to comment
Share on other sites

If this is an assumption, then all of science rests upon the same assumption. Scientists rely upon instruments, after all, and the "assumption" I made about cameras also applies to those instruments. Unless scientists "assumed" that the same instruments will work in the same way, science would be impossible.

I agree, all science relies on assumptions and as science progresses it makes less and simpler assumptions. The behaviour of instruments is not the kind of assumption I am referring to here, however, since it possible to verify if instruments are working properly. I was thinking more like, for example, Newton assumed that space and time were independent and absolute and built a system of dynamics based on that assumption.

As indicated by my earlier quote from H.W.B. Joseph, I have been discussing not a specific theory but the general principle of causal regularity, which is a necessary presupposition of all inductive reasoning and of scientific procedures that employ instruments, not to mention a number of other things. To call this an "assumption," as if science might (or already has) disproved it, is absurd. Science could not get to first base without it.

Suppose you want to fly cross-country. I doubt if you would get into your car, turn on the ignition, and expect it to fly. Nor do I think you would go from car to car, hoping eventually to find one that will fly.

Suppose someone were to ask why you would not do this. Would you say, "I assume that cars cannot fly -- but, who knows, science may eventually prove me wrong"? I hope not. In fact, you know that (normal) cars cannot fly, and you needn't worry in the least that later discoveries will prove you wrong. (I am obviously referring to cars as they presently exist, not to possible futuristic cars of the sort seen in science fiction films.)

I agree with you about assumptions of the sort made by Newton. They are tentative presuppositions of a particular theory that might be proven wrong. Given the rapid advances in science, I wouldn't be surprised if physicists a hundred years from now look upon current theories of Quantum Mechanics in the same way that we now look upon Newton's theories.

Ghs

Link to comment
Share on other sites

I wouldn't be surprised if physicists a hundred years from now look upon current theories of Quantum Mechanics in the same way that we now look upon Newton's theories.

If they do then the'll have lost it even worse than today's cast of physicists -- the fundamental difference between Newton's theories and QM is a real respect for causality. QM is not a causal theory, so it isn't even a theory, it is merely descriptive.

Link to comment
Share on other sites

Brant Gaede When I say "God is existence" I am merely making an axiomatic statement or a more complicated variation on "A is A."

You make a statement about what your idea of a god is. Existence has a god-like status for you. Equating god with existence could also be called a pantheistic position. :)

Well, I don't have reverence for or worship nature. I respect nature--reality--as I should. This is my way of criticizing the common view of God (not "a god").

--Brant

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now