My major in university was biology, with a minor in chemistry. Initially I had been interested in going on to medical school, but for various reasons decided against that. As it turns out, my various jobs and career development meant that while I never direclty worked in either field, training in the scientific method has always been a benefit. Through various stints in information technology areas, being able to create hypotheses, valid test plans and being able to analyze results has been an enormous advantage. For example, my current gig as a sales engineer supporting sales reps seeling Voice-over-IP (VoIP) systems requires that I quickly evaluate assumptions, proposed "solutions" (both as conceived by sales reps and prospective customers,) based on my company's system architecture and the true capabilities of network protocols, etc. (Note: Most of the time both sales reps and prospects are wrong.)
The nature of scientific rigor is that experimentation where variables are controlled are at the vary heart of fact-finding and the development of accepted scientific theory. Experiments, hypotheses and formulae are open to peer review, that is, repetition and testing by other parties.
All this seems very simple, yet it is subject to complexities in the "real world".
A vocal group who either deny global warming is a real phenomenon or who at the very least dismiss the human contribution to climate change invariably declare (normally in breathless, apoplectic language) that nothing is "proven", that there has been no definitive scientific proof of global warming as a trend attributable to human activity.
The problem with this, of course, is how do you conduct a controlled experiment with planet Earth as the subject? Since there is only one Earth available for observation, and we obviously cannot control all variables so as to change only one and observe the results, we can never "prove", to the satisfaction of those who deny global warming that it truly exists or is a human-influcenced/induced problem.
The proper response to this, of course, is that the question, while in the scientific realm, is not one that can be subjected to controlled observation and experimentation. In other words, it is a different, if not special, case of scientific study, just as there are special cases in all realms of study.
This is a long way of introducing a brilliant article by Showey Yazdanian, a Torontonian who is currently a PhD student at Cornell University. If I were like Bill O'Reilly and the other neo-con know-it-alls, I would tell them to "shut up". But I'm not, and I believe in open discussion, so recommend the article to you to provoke thoughtful dialogue.
No one can deny we only have one home .... one planet ... and that how we handle this issue is of enormous import.