A major feature of science, which makes it different from other human activities, is its reliance upon shareable experiences, logical rigor, reproducibility, consensus building, and the (hopefully) cheerful acceptance that our understanding of the world is incomplete and likely to remain so.

The scientific method involves gathering information, building models, testing those models through experiment and careful observation.  In some cases, this can lead to reconsidering "the facts" on which the model was built, or revising the model, which is then tested through more accurate measurements and observations.  

A good model make sense of these facts.

"Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science."- Charles Darwin. 

Tentative scientific models, known as hypotheses, are valuable and valid only in as much as they make testable predictions about the phenomena they purport to explain or predict.  

As scientific models become more sophisticated, these predictions become more and more accurate and generalized.

An important feature of a good model is the rule of thumb, known as Occam's Razor, namely that all other things being equal, the simplest explanation is the best. 

Through their predictions, scientists are able to determine whether their models accurately describe the observable world, whether something is missing, or whether they have completely misjudged the situation. 

Models are continually being modified, expanded, or replaced to make them more accurate and to explain more phenomena. 

A model that has been repeatedly confirmed is known as a theory.   For example, there are theories of gravity that explain the observation of objects falling and planets moving.  Typically, when one theory is replaced by another, the new theory explains all that was encompassed by the older theory, and more.

For example, Newton's theory of gravity was replaced by Einstein's theory of general relativity.

"The aim of science is not to open the door to infinite wisdom, but to set the limit to infinite error."  - Bertol Brecht. 

"it is the business of history to distinguish between the miraculous and the marvelous ... to reject the first ... and doubt the second." - David Hume. 

There is a small set of well established theories that underlie modern biology:

• The Physiochemical Theory of Life 
• The Cell Theory of Life and
• The Theory of Evolution

At its heart, science works as a highly interactive community.  At the same time, it is possible for a single person to challenge and change accepted scientific understanding.  

That is not to say that it is easy to change the way scientists think; after all, most challenges to well established theories are wrong, and it is generally a waste of time to think about them seriously. 

That means that a new way of looking at a phenomena must be clearly superior, both in terms of accuracy and explanatory power, to the ideas that it wishes to displace.  

It must explain more than the old ideas, and it must resolve problems that an old idea was unable to adequately explain.

It is this tension between consensus, conflict and resolution that drives scientific understanding forward, so that, in the end, more and more phenomena become explicable. 

Through its fundamental ability to accept change, science has come to provide the practical knowledge needed to manipulate and understand the material world. 

A critical, and often overlooked aspect of the scientific process is the community and long term evaluation of observations and ideas.

Observations, hypotheses and conclusions are are presented to the public in the form of scientific papers.

Another aspect of science is the embrace of "rational skepticism", an approach described in detail in this article by Peter Skrabanek

In this view of the world, certain ideas and observations are so well established that they be reasonably accepted (e.g., The Cell Theory), whereas others are extremely unlikely to be true (e.g. the possibility of perpetual motion or "free energy" machines), and so can be safely ignored. 

In general practice, it is a waste of time and energy to doubt the former, or seriously consider the latter.  

• In the day to day world, does it matter whether science ever attains the "truth" about the world?  Is the same true of religion?
• Some people claim that the "scientific establishment" is unfairly ignoring them and their revolutionary ideas; why do you think that this occurs?
• What is the difference between rational and irrational skepticism?