Yes, unchanging principles are needed. But these are some very startlingly counter-intuitive "laws of nature". For example, conservation laws in physics. Any change whatsoever cannot be caused unless some conserved abstract quantity is transferred. What the heck is energy?

EDIT:
I should tone this down a bit. Change in physics is just one of many possible types of change in nature. (I could cause a tree to grow, a bug to die, or my committee to vote no) Mechanics only involves motion. And by "caused" I might want to limit what I said to Newtonian action-reaction, where "momentum" is the conserved quantity that is passed from one system to the other. Momentum is an abstract quantity as well, but when talking about objects with mass then it could be thought of as the sum of the motion transferred.

Telos posed an insightful question on evolutionary theory here. If evolutionary traits promote survival of the species, then how is symbiosis to be explained in evolutionary theory. Else, what is missing from the theory that might help in an explanation?
Our esteemed moderator Talking Dog (td) suggested that although the theory is a method of adaptation to the environment, there is nothing in the theory about environment.

Here, I am interested in exploring the difference in interpretation of the problem between the realist and the relativist.

To the realist, the theory describes the world, and how a species got from picture A to picture B. How did a particular species come to be? How is a particular trait useful for the species? But this leads to a dilemma. Most traits are not evidently effective for survival: some are neutral, irrelevant, or even self-defeating. Symbiosis may be beneficial to the killer wasps whose larvae survive on cicadas, but not to the cicadas. Predators do not in general help the survival of their victim's species (although at times they do).

The relativist looks at evolution as a type of change, and the theory as the mechanism of that change, and nothing more. Evolution isn't going forward, nor does it help survival of any species. The key to the mechanism is in the difference in rate of change between the environment and in genetic variability. The environment is much slower! When environmental rate of change exceeds genetic variation, species die out.

This is the reason for every mass extinction in history, including the present ongoing one caused by human over-population trampling the planet. We are destroying the planetary environment faster than the natural rate of adaptation for most species.

Newton: LAW III: To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and are directed in opposite directionsEvery action has a reaction equal in magnitude and opposite in direction.

This is Newton's restatement of Galilean invariance that says that physical laws hold equally in all non-accelerated moving frames. "Invariance" is a precise, deterministic reduction of the more philosophical "relativity". While Galileo pointed out that movement is relative to the observer (Two Worlds), Newton's law specifies what happens when two systems interact. Which is that an equal amount of momentum is exchanged in opposite directions.

This implies that cause-effect are reversible in space. Each billiard ball effects the other equally. However, note that when the Sun warms the rock (Aristotle, Hume), a better explanation is that energy, a different conserved quantity is exchanged. The rock cools the Sun by an equal amount.