Science acknowledges that it cannot explain everything.

Will there still be scientists if science eventually explains all it can?

This is one of ScienceOrNot’s Hallmarks of science. See them all here.

In short…

There are aspects of the natural world that science cannot hope to understand, and within those that science can investigate, there remains much to be discovered.

Science lives at its frontiers, looking to the future, aware of the enormous scope of our ignorance.

Dudley Herschbach, American chemist, 1997

What are the limitations of science?

Science investigates natural phenomena that can be modelled and tested in the real world. It can’t deal with phenomena that can’t be modelled and it can’t deal with models that can’t be tested. Some models can’t be tested because they are not falsifiable. Others can’t be tested because the instruments or techniques necessary to make the required tests don’t yet exist.

This means that there are many questions that are beyond the scope of science. For instance, most people are convinced that science can play no part in deciding questions of morality. And science can’t contribute to  aesthetic judgements.

Are there any scientific models that are complete?

All scientific models are tentative, so none can be regarded as complete. However, many models have been tested and refined to such an extent that scientists have great confidence in them. These models explain parts of the real world very well. The chances that they will need significant further revision are very small.

In other scientific fields, the models are less reliable and scientists expect investigations and refinements to continue for a long time.

Will science ever be able to explain everything within its scope?

At various times in history, people have judged that scientists had discovered everything to be known in particular fields. They have always been wrong. Still, some scientists believe that a time will come when all scientific knowledge will be reduced to a few fundamental principles. Others believe that science won’t get this far because of the limitations of the human mental processes. Even if everything is reduced to a few fundamental laws, using them to explain particular events or phenomena would depend on knowing all the relevant conditions and having awesome computing power. Is that ever likely to happen?

Examples

• The Scottish philosopher and historian David Hume is credited with raising the is-ought problem – that factual knowledge (what ‘is’) cannot be used to make value statements (what ‘ought to be’).
• American neuroscientist and philosopher Sam Harris reasons that science can be used to make moral decisions.
• In 1900, the British physicist William Thomson (Lord Kelvin) addressed the British Association for the Advancement of Science and reputedly said “There is nothing new to be discovered in physics now. All that remains is more and more precise measurement.”  Three years later, the American physicist Albert Michelson wrote “The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote.” Within the next few years, the remarkable developments of the theory of relativity and quantum mechanics had changed the face of physics.
• The 2011 Nobel Prize for Physics was awarded to Saul Perlmutter, Brian Schmidt and Adam Riess for their discovery in 1998 that the expansion of the universe is accelerating. The only way this acceleration can be explained is that some form of ‘dark energy‘, previously undreamed of, is responsible. Dark energy makes up 73% of the universe’s mass-energy, and scientists know almost nothing about how it works. The quest for a greater understanding of this phenomenon is one of the most pressing tasks in science.

Other relevant articles

From NPR: Can Science Explain Everything?

Dudley Herschbach’s quote is from ‘Imaginary Gardens’ in The Flight from Science and Reason, p14
Albert Michelson’s quote is from Light Waves and Their Uses (1903), p 23-4

This is one of ScienceOrNot’s Hallmarks of science. See them all here.