Sir Charles Lyell - a geologist who was the first to propose that the earth was much, much older than a few thousand years. The concept of “deep time” spurred cascades of other scientific theories in a wide variety of fields, including all of biology, geology, astronomy, etc.
No one even bothered to suggest some of the more easy-to-spot discoveries and inventions:
[ul]
[li]The theory of gravity (Thanks Galileo and Newton)[/li]
[li]Speaking of that crazy guy, how about Newton’s laws of motion? Every physicist and engineer lives their whole lives praising all that is Newtonian.[/li]
[li]It’s more of an invention than a discovery, but the printing press is arguably the most influetntial piece of human creation ever. It has single-handedly allowed the proliferation of all subsequent human knowledge.[/li]
[li]Bernoulli’s principle. If we didn’t know about fluid dynamics, airplanes would still be wishful thinking.[/li][/ul]
But my vote for all-time greatest invention goes to…(drumroll please)…
[ul]
[li]Modern atomic theory. Knowing the internal structure of the atom has contributed to most of our modern advances in technology–from new soures of power (e.g. nuclear, fusion, even solar…) to electronics to quantum physics (which will be the next great life-changing field). Without knowing what’s going on inside those little bastards, we wouldn’t have any of those technologies.[/li][/ul]
If i think of anything better, i’ll make it known.
I’m too lame to have a real signature.
I don’t know if this qualifies as a scientific discovery, but what about the development of understanding of algebra and calculus? …what about the assembly line? …nuclear fission and fusion (and the theory of relativity).
Overall, my vote goes to the Harley-Davidson motorcycle.
The great and wonderful concept of zero.
Before that, the taxman knew you had something!
heh…looks like i forgot to close a bold tag in that last one
pardon my inadequacy 
Ahhh…phlogiston. I remember I wrote my SAT II Writing essay on the phlogiston theory. I forget the actual question, but it was something about how people misunderstand things. They must have liked it…I got a 740 on the test, and a 77 rating (of 80) on the essay.
Jman
I’d go with electricity.
I don’t know if you consider this to be a <i>scientific</i> discovery, but how about America, or the New World, generally? At least in Columbus’ case, reaching America was an experiment, an attempt to prove the roundness of the Earth. (Okay, so he was looking for India…)
but I also like phlogiston.
Top of mind is scientific theory. The scientific method has probably had the most effect on the world.
I may have missed it, but I don’t see DNA on the list so far.
Top of mind is scientific theory. The scientific method has probably had the most effect on the world.
What about Ohm’s law? All you Electrical people know everything in electronics is derived from it.
This is 2000… I forget, have I invented Time Travel yet?
That’s a silly question! Once invented, time travel exists everywhen. It just gives people enormous headaches, so it’s always ejected from the timestream.
Hmm. On second thought, it’s got it’s own physical laws, although we don’t know how to discover them yet. H.G. Wells’ time machine was seemingly capable of going anywhen he wanted, I’m a little fuzzy on it’s power source. Quantum Leap originally theorized that a leaper could only travel within one’s own lifetime. That was just a theory, though, 'cause Sam also theorized that a leaper would be an Observer only, unable to interact outside his own time. Then on a later leap, (which ended up being the earliest leap(see point one about headaches)) he leaped into his own grandfather, before he was born.
Seven Days, on the other hand, utilized a fixed length wormhole, that allowed the capsule to emerge 7 days before it entered, so it couldn’t travel forward (except at the usual second per second rate we’re used to), but it could take a traveler back, incrementally, to seven days before the project was created, and if the traveller had the knowledge and equipment to create the project, then they could travel back and create, back and create until the resources needed to make the project hadn’t been discovered yet. (again, see point one)
Justin Hiltscher
I was going to say fire, which allows us to smelt metal, cook food, and generate STEAM (which will, as all good disciples of Prof. Steamhead know, SAVE THE WORLD).
Or, I could just say the TAO, and tick people off.
What about man’s (and woman’s) ability to procreate freely whenever? What about the Pill, and the condom? (Incidentally, I’ve heard that in the ancient times, people used a lot of things as contraceptives…like crodocile dung…) I still say that life would be a lot more complicated if we had to use crocodile dung. It’s just hard to come by.
Double-entry bookkeeping. If you ever take Introduction to Accounting, you’ll see just how profound this idea is. Without it, it’s doubtful you could ever have an economy beyond the “haggle in the marketplace” level.
…the greatest thing ever invented/discovered/whatever is THE DISPOSABLE SANITAY NAPKIN! Before that, women used leaves or reusable cloths! Ick.
Patty
P.S. What if you accidently grabbed a poison ivy leaf?!?!?!?!
I’d have to say gravity. Where would we be without it? 