Determinism in Physics
Possibility of Non-Determinist Mechanisms
Some phenomena in Quantum physics still lack deterministic explanations. This does not prove that there's no such mechanism; three of four assumptions also allow for a determined model:
- the origin has not been discovered so far
- the origin cannot be observed at all
- the origin cannot be observed without changing the state of the system
- the behaviour is really arbitrary
** Chaotic Systems**
Even a quite simple mechanical system like a multiple pendulum, where everything may be assumed to follow known determined physical rules runs through so many unstable states that it is not possible to predict the movement of it in the long run because even a tiny difference in the assumed properties or the initial state may result in a significant deviation.
The system that integrates human thought is by far more chaotic than a physical system. We don't even fully understand our own conscious decisions; the sum of concious, unconscious action of mankind and (appearant) accident cannot be predicted in any way by humans or artificial intelligence. That is why the assumption of a purely deterministic model of the world is not helpful.
Islam
The controversy between the teaching that God holds everything in His hand and nothing can
happen against His will, and the teaching that everyone is liable for his deeds has been a subject of discussion in Islam from the beginning. We find positions that say
that
- God has fixed all what happens right from the beginning
- God established the rules of all from the beginning but the rules contain the option to break His commandments
- God is interactive, acting in the situation
All three can be backed by the interpretation of the Quran.
The first two are deterministic, the third is not.
From the chaos theory, the first two can be both true at the same time. It is possible that God has created a fully deterministic world but no-one except Him is able to forsee its development.
The key point is that even if our lives are theoretically determined, our actions, that are influenced by our belief, are part of this system and it does matter what we say and what we do.
True and false prophecy and teaching is part of this system as well.
In this sense, it's better you assume that the world is not determined (even in case that this is not really true) and take your responsibilities and follow the advice God has given us than if you give in to a misunderstood fatalism that incites you not even to try to follow His advice and do good.
Our influence on all is indeed limited, and so are our possibilities to live an ideal life. But our choice matters.
An extant and recommendable overview on this question is published on Wikipedia
