Quotes About Unobservable

Tachyons at first seem to violate causality, but physicists believe that their true purpose was to set off the big bang and hence they are not observable anymore.

it is likely that even if string theory is right, no one ever will. Strings are so small that a direct observation would be tantamount to reading the text on this page from a distance of 100 light-years: it would require resolving power nearly a billion billion times finer than our current technology allows. Some scientists argue vociferously that a theory so removed from direct empirical testing lies in the realm of philosophy or theology, but not physics.

Russell's point is not to assert his right to be left alone to his personal delusions, but that devising a theory that cannot be proved or disproved by observation is pointless in the sense that it teaches you nothing, irrespective of how passionately you may believe in it. You can invent any object or idea you like, but if there is no way of observing it or its consequences, you haven't made a contribution to the scientific understanding of the universe.

There is a philosophy that says that if something is unobservable -- unobservable in principle -- it is not part of science. If there is no way to falsify or confirm a hypothesis, it belongs to the realm of metaphysical speculation, together with astrology and spiritualism. By that standard, most of the universe has no scientific reality -- it's just a figment of our imaginations.

For many philosophers, causation is a suspicious metaphysical concept that we do best to avoid when trying to understand science. This suspicion is, again, common within the empiricist tradition. It derives from the work of Hume. The suspicion is directed especially at the idea of causation as a sort of hidden connection between things, unobservable but essential to the operation of the universe.

There will always be divergence of views on the output gap, as it is unobservable in a rigorous direct sense. There are only estimates. How can there be a strong consensus on that?