(The following is excerpted from WHY PEOPLE BELIEVE WEIRD THINGS: Pseudoscience, Superstition, and Other Confusions of Our Time (1997, W. H. Freeman) by Michael Shermer)

Sum Ergo Cogito
I Am Therefore I Think

A Skeptical Manifesto
By Michael Shermer

http://www.skeptic.com/ manifesto

The Oxford English Dictionary (OED) gives this common usage for the word skeptic: “One who, like Pyrrho and his followers in Greek antiquity, doubts the possibility of real knowledge of any kind; one who holds that there are no adequate grounds for certainty as to the truth of any proposition whatever”

It is easy, even fun to challenge others’ beliefs, when we are smug in the certainty of our own. But when ours are challenged, it takes great patience and ego strength to listen with an unjaundiced ear.

A sizable body of literature exists on the scientific method and there is little consensus among the authors. This does not mean that scientists do not know what they are doing. Doing and explaining may be two different things. For the purpose of outlining a methodology for the rational skeptic to apply to questionable claims, the following four step process may represent, on the simplest of levels, something that might be called the “scientific method”:

1. Observation: Gathering data through the senses or sensory enhancing technologies.
2. Induction: Drawing general conclusions from the data. Forming hypothesis.
3. Deduction: Making specific predictions from the general conclusions.
4. Verification: Checking the predictions against further observations.

Science leads us toward rationalism: the basing of conclusions on the scientific method. For example, how do we know the Earth is round?:

1. The shadow on the moon is round.
2. The mast of a ship is the last thing seen as it sails off the horizon.
3. The horizon is curved.
4. Photographs from space.

And science helps us avoid dogmatism: the basing of conclusions on authority rather than science. For example, how do we know the Earth is round?:

1. Our parents told us.
2. Our teachers told us.
3. Our minister told us.
4. Our textbook told us.

Dogmatic conclusions are not necessarily invalid, but they do pose another question: how did the authorities come by their conclusions? Did they use science or some other means?

The Tool of the Mind Science is the best method humankind has devised for understanding causality. Therefore the scientific method is our most effective tool for understanding the causes of the effects we are confronted with in our personal lives as well as in nature. There are few human traits that most observers would call truly universal.
Most would consent, however, that survival of the species as a whole, and the achievement of greater happiness of individuals in particular, are universals that most humans seek.
We have seen the interrelationship between science, rationality, and rational skepticism. Thus, we may go so far as to say that the survival of the human species and the attainment of greater happiness for individuals depend on the ability to think scientifically, rationally, and skeptically.

One of the characteristics that sets man apart from all the other animals (and animal he undubitably is) is a need for knowledge for its own sake. Many animals are curious, but in them curiosity is a facet of adaptation. Man has a hunger to know. And to many a man, being endowed with the capacity to know, he has a duty to know. All knowledge, however small, however irrelevant to progress and well-being, is a part of the whole. It is of this the scientist partakes. To know the fly is to share a bit in the sublimity of Knowledge. That is the challenge and the joy of science.