Why the mechanism of everything in the universe has a pattern? why everything in the universe has a pattern which can be identified and understood to determine outcomes, properties, effects of almost everything. I am saying that couldn't the universe be like patternless, non-deterministic and chaotic. For example why the gravitational force between any two objects has a pattern which always obeys universal law of gravitation and can be predetermined. Couldn't be the gravitational force between any two given objects would have no pattern and would be completely random and non-deterministic. Is this property of universe in which everything has a pattern is a complete matter of chance or it is a property of even something fundamental.
 A: As a matter of fact, we do have a quantifying parameter for chaos, which is Entropy.
In terms of entropy our universe is chaotic, but for better or for worse, this chaos seems to increase monotonically with the passage of time, which is a predictable feature, unlike what you would want. Maybe in future, its possible that someone would come up and say that everything that is predictable about this nature stems out of this peculiar feature. As of now, this is an open problem commonly called as the Arrow of time.

Coming to you question as to why Predictability -
If the universe weren't predictable, as in absolutely chaotic, that would mean that entropy has reached a maximal state, there cannot be any more chaos!! Now, unchanging parameter of a system (including entropy) is the characteristic of equilibrium state. As a matter of fact, if everything where to be in equilibrium, NO LIVING SPECIES CAN EXIST. We feed ourselves each day in a strive to maintain a NON-equilibrium state, that's what keep up alive - CONSTANT INPUT OF ENERGY.
Hence, the very existence of living species can be attributed to the fact that we are living in a non-equilibrium world.
So essentially my claim is that, although as you have imagined, we cannot eliminate the possibility of a universe with absolutely no pattern (and such a universe may exist somewhere), but for us its sufficient to know that the universe we live in is predictable and we know that through BIOLOGY, for one thing.
A: Humans like looking for patterns in nature and when we find them we show each other in books, lectures etc...
It is remarkable that so many patterns have been discovered.
However there are lots of things where patterns haven't been found, we probably don't talk about those as often, especially on 'Physics StackExchange'.
Even within physics there are things where there doesn't seem to be a pattern, or at least not a known one.  For example the value of the fine structure constant or the masses of the particles, the radii of the planets etc...
A: Physics isn't very good with why questions. The business of physics is to find and describe the patterns. However at least a little can be said.
The universe if full of particles. Many of these particles are the same. For example, every electron is just like every other electron, aside from such differences as some are moving fast and some are slow. If you give two electrons the same speed and so forth, they will behave the same. So if you can figure out a property of one electron, you can use that property everywhere.
Likewise space is uniform and isotropic. Time is uniform. An electron at one spot and time has the same properties as at another. Again, except that space time is curved differently in different spots. Curvature is determined by nearby matter and energy. Give any two times and places with the same curvature and any other properties, they will behave the same.
So if the force between a given pair of electrons is $$F = 4 \pi \epsilon_0 \frac{q_e q_e}{r^2}$$
this is a pattern that works everywhere.
