In everyday language, a theory is something that hasn’t been proven. We use it to mean ‘hypothesis’.

I don’t know why socks go missing but I have a  theory.

MARK COLVIN: Do you think that to a degree [the theory of evolution is] a communication failure by science? Do you think that just the very word, “theory”, in the “theory of evolution” has misled people?

RICHARD DAWKINS: Yes, I think that’s not the only communication failure. I think that simply not bothering to go out there and talk in the public square is part of the problem.

– from this interview.

Here’s how the word ‘theory’ works in scientific literature, compared to some similar words:

  • Hypothesis–>An educated (or uneducated) guess
  • Science Method–>The 7 step process to test said guess
  • Theory–>The “why” of something works
  • Law–>The “what” of something that works

courtesy of Freethought Blogs.


In common usage, ‘natural’ = ‘good’.

The Incredible Arrogance of Thinking ‘Natural’ Means ‘Good’

This one is a marketing difference and it pays to remind oneself regularly: brown packaging and ‘natural’ on the box doesn’t mean jack. Cancer. That, too, is ‘natural’.


A college professor taught me the word “casuistry” when it came up in office hours during a conversation we were having about a presentation I was slated to give on John Donne. It has two definitions: the first more technical definition has something to do with applying abstract rules to concrete instances. The second, in more common usage, is something like “specious, sophistic reasoning.” It’s especially associated with the Jesuits, who (allegedly) used it to rationalize light punishments for aristocratic sinners. It’s a great word. I especially like to use it when I’m losing an argument, because even if, say, my husband is being perfectly logical, nothing undermines a debate by calling him a casuist.



In science, symbiosis means ‘a close relationship’. There are four main kinds of symbiosis, one of which is mutualism.

In everyday English, when people talk about ‘a symbiotic relationship’ we are most often talking about mutualism, or ‘a mutual relationship’, which would be technically more accurate.

Apart from mutualism,  three other types of symbiosis are:

  1. Commensalism, in which one species benefits while the other remains unaffected
  2. Parasitism, in which one species benefits while the other is harmed
  3. Neutralism, in which both species are unaffected


Common Usage: Man-made chemicals

Scientific Usage: Biologically produced poisons.

(Toxoid: A toxin which has been rendered no longer toxic eg. a vaccination is ‘toxoid’, which doesn’t exactly help the vaccination cause.)




from A Comprehensible Universe: The interplay of Science and Theology


Scientists generally use the term “epidemic” to refer to a disease that occurs suddenly in a discrete population, an outbreak. An epidemic is not declared on the basis of high numbers but on the speed or rate that new cases pop up. In the nineteenth century, the word was used almost exclusively to describe a wave of infectious disease. In the typical graph of an epidemic, the number of cases is plotted against a measurement of time, such as days or weeks, to show how quickly the disease is spreading.

With the notable exception of AIDS, in modern times we’ve had less experience than previous generations with fast-moving infectious diseases, like polio or smallpox, that can affect entire populations. As a result, the time component of the definition of an epidemic has become less crucial. As one consequence, the definition of ‘epidemic’ has broadened. Now, we use the word with little reference to the speed at which new cases are occurring, which puts us one step away from the original usage. And when we talk about epidemics of conditions that are not contagious — such as skin cancer, autism, anorexia nervosa, and teen pregnancy — or conditions and situations that are not even real diseases — like alien abduction, or satanic child abuse — we’re two steps away.

Unstrange Minds: Remapping the World of Autism by Roy Richard Grinker

Related Link

What scientists say in research papers vs. What they actually mean, from io9