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Okay, so astrology to me sounds extremely unscientific. But I haven't read anything on the subject, and other than knowing that it's something a lot of scientists thing is.. unscientific. To be perfectly fair, I can't just dismiss it because other people dismiss it.
I'd like to be able to dismiss it for scientific reasons. Because I was reading my horoscope, and I was like, "Hmm, well these are extremely vague statements that could apply to anyone and I don't particularly identify with." But then I was reading a friends, and I majorly freaked out because of how accurate it was.
So because of that, I now want to know the truth. Either astrology works or it doesn't. Does anyone know how I could go about determining this? I mean, does anyone have any books or online articles that they would recommend? I'd really appreciate it. I just want to understand.
Arguments from authority are invalid, but they are often inductively strong. If a community has a good track record for having good judgement within a given domain, then any particular judgement they make within that domain is evidence (sometimes weak, but sometimes strong) for the truth of their judgement. Arguably, scientists have relevant expertise in recognising what is and isn't science.
No they aren't. Incorrectly applied arguments from authority are often invalid but the form of argument is not itself intrinsically invalid. You do acknowledge this in your reasoning but I'd like to emphasize that the initial conclusion "Arguments from authority are invalid" isn't actually correct and that the 'inductive strength' makes the arguments valid when used correctly.
An argument is valid if and only if the truth of its premises entails the truth of its conclusion.
The truth of the premises of an argument from authority does not entail the truth of its conclusion.
Therefore, arguments from authority are not valid.
Note: This argument is valid in the sense I am using the term.
If your use of the term valid is such that arguments from authority are (necessarily) invalid then your use of the term is simply wrong. The very wikipedia link that you provide explains it as one of the many forms of potentially valid argument that is often used fallaciously. The following is an example of a valid argument form:
If you wish to trace the error in conclusion back to a specific false premise then it may be the (false) assumption "All valid arguments are deductive arguments".
That argument is not valid. Valid arguments don't become invalid with the introduction of additional information, but the argument you provided does. For instance, compare these two arguments:
1.)
All men are mortal.
Socrates is a man.
Therefore, Socrates is mortal.
2.)
All men are mortal.
Socrates is a man.
Socrates is in extremely good health for his age.
Therefore, Socrates is mortal.
This argument will stay valid no matter how many additional premises we add (provided the premises do not contradict each other). Here is a variation of the argument you provided with additional information:
Person X has reputation for being an expert on Y.
Things said about Y by a person who has a reputation for being an expert on Y are likely to be correct.
Person X said Z about Y.
Person X said Z because he was paid $1,000,000 by person A.
Person X doesn't really believe Z.
Z is likely to be correct.
There is no contradiction between an argument having arbitrarily high inductive strength (like the very best arguments from authority) and still being invalid.
Not only is it valid it is trivially so. It does not even rely on the possibility of there being valid inductive arguments. I made it the most simple of deductions from supplied premises.
Your problem here seems to be that you object to deducing a conclusion of 'likely to be' from a premise of 'likely to be'. By very nature of uncertain information things that are merely likely do not always occur and yet this does not make reasoning about likely things invalid so long as uncertainty is preserved correctly. (The premise could possibly be neatened up such that it includes a perfect technical explanation with ceritus paribus clauses, etc but the meaning seems to be clear as it stands.)
If the argument was in the form of a deduction when only an induction is possible from the information then the appeal to authority is invalid. If the argument is a carefully presented inductive claim then it most certainly can be valid.
Not all arguments are deductions. Not all arguments that are not deductions are invalid.
Jayson_Virissimo is talking about logical validity. The argument is not logically valid, because it is possible for "Z is likely to be correct" to be false, even if the other statements are true (for instance, add the premise "Z is incorrect"). Induction is not (in general) logically valid. It's valid in other senses, but not that one.
Yes, we both are. We have gone as far as to accept a shared definition of logical validity and trace the dispute from there.
This is simply false. The following premise:
... becomes invalid the moment there is in fact a "thing said <etc, etc>" that is not likely to be correct. That's why I put it there! It is an instance of the class of premise "ALL G ARE W" and so just like all other premises in that class it is false if there is a G that is NOT W. it just so happens that 'likelyhood' is the subject matter here.
The above serves to make the premise in question rather brittle. While it does means that the whole argument can be treated as deductive reasoning (about the subject of likelyhoods) it is also means that there are very few worlds for which that premise is true and meaningful.
I interpreted your premise as: (Things said about Y by a person who has a reputation for being an expert on Y) are likely to be (correct.) as opposed to (Things said about Y by a person who has a reputation for being an expert on Y) are (likely to be correct.)
If, as you seem to be agreeing, a thing cannot be "likely to be correct" and "incorrect" (as known by the same reasoner), then the premise reduces to "Things said about Y by a person who has a reputation for being an expert on Y are correct".
Is this really what you intended?
No it cannot.
That which is said to be invalid in the text that you link to (things such as generalizing from anecdotes to make mathematically certain claims about a set) is not the same kind of reasoning as that which we are talking about here. Here we are talking about probabilistic arguments, about which you say:
That leaves us at an impasse. There is not really much more I can say if you pit yourself against what is a foundational premise of this site: That the correct way to reason from evidence is to use Bayesian updating. You have essentially dismissed the vast majority of all useful reasoning as invalid. I disagree strongly.
The terms "valid" and "invalid" have a precise logical meaning; that is the meaning Jayson_Virissimo intends, as they have said many times now.
As you are using them, you seem to mean "well-grounded, justifiable, effective, appropriate, and etc."
Really this all could have been avoided if you all had just taboo'd the offending terms.
You are correctly restating my claim. The vast majority of all useful reasoning is invalid. And by "invalid" I mean that it would not be self-contradictory to affirm the premises and deny the conclusion.
What? Of course it's valid (logically). The first three statements are premises and the final statement is the conclusion, which is entailed by the premises. If things said about Y by person X are likely to be correct and person X says Z about Y then Z is likely to be correct. That's a trivial deduction.
The argument is however not necessarily sound, because the premise "Things said about Y by a person who has a reputation for being an expert on Y are likely to be correct" is not universally true, for example if the person is saying stuff which blatantly contradicts other far stronger evidence.
Edit: Okay, enough silliness. Here is a formalised version of the above argument. You could run it through a proof checker, probably.
This argument is valid. It is not sound, because premise 2 is false. This is basic logic.
Probabilistic arguments are not the same as logical arguments. A Logical argument contains all information pertinent to the argument within itself. A probabilistic argument, by including words such as likely or probably, explicitly states that there is information to be had outside the argument. Probabilistic arguments are necessarily changed with the inclusion of more information.
Agreed. Probabilistic arguments are necessarily invalid (except when the probability of every relevant premise is equal to 1).
Is this an example of the persuasion tactic advocated (or described) recently? That is, you open with 'agreed' and then clearly say something that would undermine drethelin's whole comment.
No. I affirm all 4 sentences in drethelin's comment. Also, I maintain that nothing in drethelin's comment contradicts anything I have said in this discussion.
Really I just think he's using a stupidly strict definition of "Valid"
The link I provided (here) does not contain the string "valid" as of 01:43 1/22/2012 Phoenix, Arizona time. What is does say is:
Inductively Strong != Valid
That is more than a tad disingenuous. You seem to be trying to claim that because the string 'valid' is not present in the text the clear meaning of the text cannot be that arguments from authority can be valid. I hope you agree that this sounds silly if made explicit. Things that are present in article are the phrase 'statistical syllogism' and the inclusion of "Fallacious appeals to authority" as a whole seperate subsection. That section opens by explaining:
... This is an explanation of how fallacious arguments from authority differ from valid ones.
Yes, this is exactly my position.
That is indeed a valid argument-form, in basic classical logic. To illustrate this we can just change the labels to ones less likely to cause confusion:
The problem arises when instead of sticking a label on the set like "Snarfly" or "bulbous" or whatever you use a label such as "likely to be correct", and people start trying to pull meaning out of that label and apply it to the argument they've just heard. Classical logic, barring specific elaborations, just doesn't let you do that. Classical logic just wants you to treat each label as a meaningless and potentially interchangeable label.
In classical logic if you make up a set called "statements which are likely to be correct" then a statement is either a member of that set or it isn't. (Barring paradoxical scenarios). If it's a member of that set then it is always and forever a member of that set no matter what happens, and if it's not a member then it is always and forever not a member. This is totally counterintuitive because that label makes you want to think that objects should be able to pop in and out of that set as the evidence changes. This is why you have to be incredibly careful in parsing classical-logic arguments that use such labels because it's very easy to get confused about what is actually being claimed.
What's actually being claimed by that argument in classical logical terms is "Z is 'likely to be correct', and Z always will be 'likely to be correct', and this is an eternal feature of the universe". The argument for that conclusion is indeed valid, but once the conclusion is properly explicated it immediately becomes patently obvious that the second premise isn't true and hence the argument is unsound.
Where the parent is simply mistaken in my view is in presenting the above as an instance of the argument from authority. It's not, simply because the argument from authority as it's usually construed contains the second premise only in implicit form and reaches a more definite conclusion. The argument from authority in the sense that it's usually referred to just goes:
That is indeed an invalid argument.
You can turn it in to a valid argument by adding something like:
2a. Everything Person X says about Y is true.
...but then it wouldn't be the canonical appeal to authority any more.
Here's a link:
http://rationalwiki.org/wiki/Astrology
In brief, there is no evidence from properly conducted trials that astrology can predict future events at a rate better than chance. In addition physics as we currently understand it precludes any possible effect on us from objects so far away.
Astrology can appear to work through a variety of cognitive biases or can be made to appear to work through various forms of trickery. For example when someone is majorly freaked out by the accuracy of a guess (and with a large enough population reading a guess it's bound to be accurate for some of them) that is much more memorable and much more likely to be shared with others than times when the prediction is obviously wrong. As such the availability heuristic might make you think that such instances are far more common than they actually are, while the actual frequency is entirely explicable by chance alone.
So our world would look exactly the same without astronomy? (I'm kidding of course but that statement should require further qualification)
Here's a really neat chart from OkTrends (a blog discussing data from the dating website OkCupid) showing match percentages between people of various astrological signs, based on similarity between the users' answers to a wide range of questions:
http://cdn.okcimg.com/blog/races_and_religions/Match-By-Zodiac-Title.png
The data there implies pretty strongly that astrological sign has no predictive ability when it comes to a person's self-description.
Unless they had several thousand couples for each one of the 144 cells, I'm very surprised there weren't bigger fluctuations due to chance alone. (And that single “59” shows that they didn't round all numbers to the nearest ten.)
Indeed they did -- about 868 million couples per cell by my reckoning, or about half that if they're only pairing based on preferred gender:
Sorry, I should have linked the article earlier instead of just the chart.
On sample size: Keep in mind that it isn't couples that are being looked at here, just comparisons between users' self-reports. Specifically, each question has two answers: The user's self-report, and what they would want a potential date to answer. The compatibility percentage is based on matching from A's wants to B's reports and vice-versa.
For the article, data was collected from a randomly selected pool of 500,000 straight users. The gender balance among straight users is about 60% men, 40% women, so that's about 25,000 men in each row and 17,000 women in each column. So each cell has about 400 million comparisons.
As OtherDave said, all you need is a blind-test. You need to read the horoscopes WITHOUT KNOWING WHICH ONE IS WHICH; then grade them on "accuracy" still without knowing which one is which. Only after you've written the grades down, you should check whether they correspond better than chance would allow.
A simple exercise to see whether further theoretical research is justified might be to have a friend print out the horoscopes for all the Zodiac signs or whatever, remove identifying characteristics from each one, and have you rank all of them every day for a month in terms of how accurate they are. Then see whether the horoscope accuracy correlates better with the ones for your sign than the ones for other signs.
More doable than my idea. Upvoted.
How'd it go?
EDIT: My bad, I thought this was posted on 22 January 2013, not 22 January 2012. I'll leave this up just in case though.
You should read the essay "Science: Conjectures and Refutations" by Karl Popper. In short, although astrology may use things like observation, it is not scientific. Why? Well you answered your own question, it's made up of extremely vague statements that will always be true. The virtue of a scientific theory is not in its ability to be proven true, but its ability to be proven untrue.
Let me use a simple analogy:
Let's say I tell you that I have a theory about why people commit murder. I say the sole reason why people are killers is because they had poor relationships with their parents, or if they were orphans with the major adult figures in their lives.
Now, say we look at some samplings of convicted murderers, there are no cases where you can not interpret their childhood as satisfying my criteria above.
I'm anticipating some disagreement with what I've said, so let me find some random examples and I'll try to show how each can be interpreted to agree with my hypothesis no matter the case.
I'm simply going to go through a few of the people on this list: http://en.wikipedia.org/wiki/List_of_serial_killers_by_number_of_victims
First one "Luis Alfredo Garavito Cubillos": Here is a short blurb about him,
"Garavito's victims were poor children, peasant children, or street children, between the ages of 8 and 16. Garavito approached them on the street or countryside and offered them gifts or small amounts of money. After gaining their trust, he took the children for a walk and when they got tired, he would take advantage of them. He then raped them, cut their throats, and usually dismembered their corpses. Most corpses showed signs of torture."
This fits my original hypothesis because the victims were all children. Clearly he had a poor childhood as a result of the upbringing his parents gave him, which resulted in his neuroses and violent thoughts towards children. The fact that he gave them gifts also shows that his parents most likely had a poor relationship with him, and he is expressing negative behavior towards typical parent-child actions such as giving a child candy or gifts.
Let's look at another one.
"Daniel Camargo Barbosa" : According to wikipedia "Camargo's mother died when he was a little boy and his father was overbearing and emotionally distant. He was raised by an abusive stepmother, who punished him and sometimes dressed him in girls clothing, making him a victim of ridicule in front of his peers"
This obviously fits the hypothesis as well, his mother was abusive, so it fits the hypothesis. We're doing pretty good with this idea right?
And another one: "Ahmad Suradji"
"He told police that he had a dream in 1988 in which his father's ghost told him to kill 70 women and drink their saliva, so that he could become a mystic healer"
The reason why he committed his crimes is because of his relationship with his father, which is evident by the "ghost of his father" telling him to kill the women.
And yet another one: "John Wayne Gacy"
"Throughout his childhood, Gacy strove to make his father proud of him, but seldom received his approval: One of Gacy's earliest childhood memories was of being beaten with a leather belt by his father at the age of 4"
This also fits my hypothesis, he had a poor relationship which lead to him becoming a killer.
That's enough, I think my point has been made. In any situation the evidence could be interpreted as confirming the original hypothesis even if there was no clear evidence that it was their relationship that caused them to become serial killers
This is what's known as post hoc ergo propter hoc reasoning: http://en.wikipedia.org/wiki/Post_hoc_ergo_propter_hoc and it also falls under confirmation bias: http://en.wikipedia.org/wiki/Confirmation_bias
If my original hypothesis had been more specific, such as "all people who have poor relationships with their parents or parental figures will become killers" then it would be much easier to disprove, and thus a much more useful hypothesis.
One of the things that most believers in astrology will do when presented with refuting evidence is to use interpret the evidence in such a way that it either does not refute astrology or confirms it. If you look at any scientific theory you will see that it's possible for it to be wrong if there is evidence that refutes it, and in fact there are many cases where scientific theories have been proven wrong by observations made after formulating the hypothesis.
The key idea to show why astrology doesn't work in my opinion is its lack of riskiness, you may feel that the statements are very accurate, but this is only due to the fact that they are meant to be overly generic.
The stuff you find in newspapers aren't really horoscopes.
Anyway... I seem to remember that some organisation in India drew up a bunch of horoscopes of normal kids, mixed in a bunch of horoscopes of disabled kids, and challenged astrologers to figure out which were which.
You could do something like that, if you had the inclination to study the subject... Have a lot of LWers drop in their horoscopes (there's gotta be a horoscope creation tool somewhere on the internet) and see if you can deduce their major life events. Or pay an astrologer to do it.