Most scientists like to operate in the context of economy. If you don't need an explanatory principle, don't invoke it.
String theory has the potential to show that all of the wondrous happenings in the universe - from the frantic dance of subatomic quarks to the stately waltz of orbiting binary stars; from the primordial fireball of the big bang to the majestic swirl of heavenly galaxies - are reflections of one, grand physical principle, one master equation.
While the broad principles of democracy are universal, the fact remains that their application varies considerably ... We are at the beginning of the road, at the very beginning. We still have a long way to go.
Any positive thinker is compelled to see everything in the light of his own convictions.
Belief is a good thing in principle, but an annoying thing in human beings.
... There must then be a principle of such a kind that its substance is activity.
...The entire preoccupation of the physicist is with things that contain within themselves a principle of movement and rest.
It is clear, then, that wisdom is knowledge having to do with certain principles and causes. But now, since it is this knowledge that we are seeking, we must consider the following point: of what kind of principles and of what kind of causes is wisdom the knowledge?
...virtue is not merely a state in conformity with the right principle, but one that implies the right principle; and the right principle in moral conduct is prudence.
No science ever defends its first principles.