Because

I was rigorously trained as a scientist years ago, and I am a divergent thinker. So I like to ponder, wonder, and hypothesize about all nature of things, but I am exacting in my process.

People – including reporters, writers, doctors (and even scientists themselves!) – are often confused about the principles of scientific thought and practice, and so they have difficulty understanding, interpreting, and critiquing scientific results, and explaining them to others.

Here are some basics.

The main work of science is prediction. Scientists, through hypothesis and experiment, try to establish the ‘rules of operation’ for any system, so that future events can be predicted. This traditional scientific method works well for systems that are linear¹ and have only one aspect that varies, which in the real world are few. But complicated problems can often be broken down into smaller ones that lend themselves to this type of investigation. Medical drug trials are a common example. Climate modeling is not.

Scientists start with hypotheses. Good hypotheses derive from known, previously established scientific relationships, and from new observations. Scientists may observe associations between phenomena and question, “Are these events, occurrences related?”

For example, many lung cancer patients were found to be tobacco cigarette smokers, and it was a strong association. Strong associations are called correlations. The work of science is to establish if correlated events/occurrences have a causal relationship, i.e., if one thing causes another. After many initial experiments (and many experiments that replicated the initial results) it was established to the satisfaction of scientists, if not the tobacco industry, that cigarette smoking does indeed cause (some forms of) lung cancer.

Bad science thinking comes from confusion about associations, correlations, and causal relations. And we are confused for a good reason – human beings are made to see patterns. Recognizing patterns is essential for survival, and it is a habit of mind all creatures share, predator or prey. The problem is, we often make or see patterns that are not real or meaningful. The word for this very human condition is apophenia.

Here are a few suspect associations:

– The alignment of stars, planets, and moons at birth WITH personality and fate
– Consumption of cholesterol WITH heart disease
– Any one strong storm (winter, tornado or hurricane) WITH climate change

The scientific method is a process to sort through patterns and overcome apophenia. Scientists examine associations to find those that are strongly related. Then they hypothesize about the causes of these correlations, and test their hypotheses with experiment. Successful hypotheses become theories, the tools used to predict the future. Apophenia leads us to skip over the middle steps that science rigorously takes, and draw incorrect connections. We jump to conclusions.

Let’s look more closely at the claims of astrology. Historically, associations have been made between personality and the complement of stars, planets, and moons present in the sky at birth. Scientists discount these associations as non-real patterns, because they have not found/cannot find causal relationships. Specifically, there are no ways that heavenly bodies exert a physical effect that determines genotype (our biological blueprint) or affects fetal development.

For many observers though, the correlation holds up, even as the causal relation fails. People born in March are headstrong, those in January are inventive etc. How can we think about this scientifically? Sometimes, one condition that correlates with another, though not its cause, stands in for something that may be.

To apply this reasoning to astrology, you might observe that the regular appearances of heavenly bodies also correlate with the seasons, which in turn, correlate with the calendar. A scientific question to ask is, “Might there be a seasonal effect on genotype or development that is expressed in personality?”

One biological pathway to pose for this is hormonal. There are many independent, established scientific observations and conclusions that are suggestive and consistent. Here are three: Human hormone levels are known to fluctuate, for many external reasons; humans are known to be strongly affected by environmental conditions like night and day; brain development in utero is known to be strongly affected by a mother’s testosterone levels.²

Good questions to ask and investigate come out of this deeper look into associations:
Do seasonal variations affect pregnant women’s hormone levels? How?
Do pregnant women’s hormonal variations affect fetal development? How?
If found, do any variations in fetal development affect/determine personality, psychology or intellect?

There are many, many investigative steps to take in order to establish every one of these connections, before giving astrology any due. But if they all hold, rigorously, constellations might be a stand-in for seasons,³ and as such might be a shorthand indication of seasonally determined biological traits …

Science is not fail-proof. But it is a good practice to refine our pattern-making into useful understandings. Scientific thinking has a place outside the profession too. We can all learn to be critical and cautious about the patterns we see.
Don’t jump to conclusions!

1. Linear systems are simply proportional, and are easily described mathematically and graphically. Many non-linear systems are regular too and can be described mathematically; these are also predictable.
2. High levels of testosterone strongly develop the right hemisphere of the brain, the seat of musical, spatial and mathematical thinking.
3. Although, because the Earth wobbles like a top (very very slowly), the correlation of the constellations with the seasons + calendar is changing gradually. So that astrological dates now correlate with constellations differently than they did 2000 years ago. For example, Aries now appears later, between April 18- May 13. But rather than indicating you have traits associated with Pisces if you are born at the end of March, a scientifically established relationship between seasons and traits would mean instead that Pisces are headstrong, not Aries!