Question: "What is fatalism? What is determinism?"
Let’s begin with some general definitions:
Determinism: The view that every event has a cause and that everything in the universe is absolutely dependent on and governed by causal laws. Since determinists believe that all events, including human actions, are predetermined, determinism is typically thought to be incompatible with free will.
Fatalism: The belief that "what will be will be," since all past, present, and future events have already been predetermined by God or another all-powerful force. In religion, this view may be called predestination; it holds that whether our souls go to heaven or hell is determined before we are born and is independent of our choices.
Free will: The theory that human beings have freedom of choice or self-determination; that is, given a situation, a person could have done other than what he did. Philosophers have argued that free will is incompatible with determinism.
Indeterminism: The view that there are events that do not have any cause; many proponents of free will believe that acts of choice are capable of not being determined by any physiological or psychological cause.
Theological fatalism is an attempt to demonstrate a logical contradiction between an omniscient God and free will, where free will is defined as the ability to choose between alternatives. In this it is similar in purpose to the conundrum "Can an omnipotent God make a rock so heavy that even he is not able to lift it?"
Theological fatalism’s premises are stated as follows: God is omniscient. Since God is omniscient, God has infallible foreknowledge. If God has infallible foreknowledge that tomorrow you will engage in an event (mow the lawn), then you must invariably engage in that event (mowing the lawn).
Therefore, free-will is not possible, since you have no alternative except to engage in the event (mow the lawn). In the event that you do not fulfill event, then God is not omniscient. Alternatively, if you engage in event, then you don't have free will, on account of your inability to choose an alternative.
An opposing argument can state that God is omniscient. Since God is omniscient, He is also infallible. If God has infallible foreknowledge that tomorrow you will engage in an event, then you will freely choose this based on your free will, not out of obligation or lack of choice about the event. You still have free will to engage in the event; God merely knows your choice before you make it. You are not obliged to make choice 'A' (mowing the lawn) any more than choice 'B' (playing tennis). If you were going to change your mind, God would have seen that also, so you still have full free will in all matters. Also, you will still make the same choices (with free will), even if God chose to not see the future. God’s seeing or not seeing the future does not alter your free will.
Passive foreknowledge, if it were kept hidden, would not invalidate free will in any logical or rational way. The individual choosing event 'A' would be making the same choices regardless of whether or not God knew the choices beforehand. God knowing or not knowing the future (passively) would not alter the free will of individuals at all. Free will would only be destroyed if God made His knowledge public in regard to the freewill choice of individuals; this would alter future free will and make it an obligation. A simple illustration is a psychic person foreseeing someone on the other side of the world tripping and breaking his leg when he runs to catch a bus. The psychic would not be altering reality by foreseeing this event, as this event would still happen regardless of whether someone had seen it or not. The same applies to God's omniscience: as long as it is passive and not interfering with reality or another's knowledge of it, then it is not contravening the free will of humans.
However, if God created all that is, then that poses a problem for any passive knowledge on God's part. An understanding of omniscience must be joined with an understanding of God's omnipresence in time. If God knows all events—past, future, and present—then He would know all events and decisions an individual would make, though from the individual’s perspective those events and decisions have not yet occurred. This might imply a nullification of free will for any individual, although no mechanism for God's apparent foreknowledge restraining the freedom to act is posited by the principle of theological fatalism. Since, according the Christian theology, God is atemporal (existing outside of time), God knows from creation the entire course of one's life and even whether or not that individual will accept His divine authority. With these preconditions, only a starkly fatalistic theological position seems imaginable to some.
To go one step further, here are some other implications: there is a vast difference between Predestination, Fatalism and Chance (or Fortune).
Fatalists teach that there is a blind, impersonal force, over which no one has control—not even God—and that events are swept along by this blind, purposeless power. This is Fatalism.
Chance (or Fortune) is a capricious force that supposedly causes things to happen “luckily,” without any control or direction by God. In a world ruled by Chance, God can foresee what will happen, but that is all. Everything depends on mere luck. And if the advocate of Chance is asked why or how things come to pass, he has no reply except to say that "it just happened."
Predestination, the doctrine of the Bible, says that God has a purpose and He is working all things out according to His own will and purpose (Ephesians 1:11; Daniel 4:35; Isaiah 14:24; and 46:10). Predestination teaches that God neither does nor permits anything except what serves His purpose (Psalm 33:11). This means that GOD IS the SOVEREIGN of the world, the One who does all things as He wills.
Those who blindly believe "whatever will be, will be" are as wrong as the advocates of chance. It is true that events are certain, but only so because of the sovereign God who fulfills His own decrees.
Serious students of the Bible do not believe that things “just happen." They understand that a wise, holy, good and sovereign God has control of every detail of life (Matthew 10:29-30). The man who does not really want God to have this control, or who despises the truth of God’s sovereignty, is the person who does not love God and does not want God in his life. He wants his own way. He, like the devils of old, would say, "Leave us alone" (Mark 1:24). But not so; God is sovereign, and He cannot deny Himself.