Introduction

Chapter 1 of your textbook includes the following:

Science is "a systematic process for learning about the world and testing our understanding of it.” A few paragraphs later it says, "Scientists examine ideas about how the world works by designing tests to determine whether these ideas are supported by evidence."

We pay attention to what is happening around us and try to understand it.  When we think we understand how two things relate to each other we design an experiment or watch a natural experiment (Read "The Nature of Science" in your textbook for more details.).

A number of people in our society put some faith in astrology, the belief that the alignment of the stars at your birth can be studied to understand your personality and predict your future.  Using your horoscope to predict events falls into the realm of “pseudoscience” because it lacks scientific support.  It is easy to design a scientific test of astrology.  In lab this week we will test the validity of horoscope predictions using the generally accepted astrological signs and we will also test a variation that some believe is an improvement.

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The Scientific Method

One important aspect of the scientific method is hypothesis testing.  A hypothesis is an idea that is based on observations.  Newton is said to have generated his ideas of gravity after observing an apple falling out of a tree.   His ideas did not become a part of the body of science until they were tested.  Some of the predictions were not correct and new hypotheses were generated, based on the results of experiments.  His ideas about gravity were not scientific because they used a complicated formula or because they were difficult for most people to understand.  What made his ideas scientific was the fact that they could be tested and potentially be shown false.  This is the key to a scientific experiment.  We must be able to show that a prediction is false.  This is called “disprovability”.  Today we will try to disprove the ability of horoscopes to predict the future. 

 

Testing Horoscopes

If astrological predictions are supposed to be accurate than all we have to do is show that they are sometimes wrong to disprove them.  This may be a little harsh because horoscopes might be of some value if they were usually right or were pretty close even if they are not quite perfect.  You probably even know someone who has told you about how perfect their horoscope matched what happened to them once.  Could this be sheer chance?  Is a prediction helpful if it is wrong 9 times out of 10?  I am going to suggest that horoscopes are completely made up and that it is only a matter of chance if they happen to say something that applies to you on a given day.

The hypothesis we will test today is, “Horoscopes are accurate more often than random chance”.

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