What is the basis of belief in G-d? How do you know that G-d exists?

We know of G'd's existence. Rambam (Moses Maimonides - 13th century scolar) defines G'd as the first cause. So, regardless of how one might believe we got here: big bang, evolution, entropy theory etc, one would need the cause that began the system.

 

Since this first cause always existed, it will always exist (you can't stop the car if you never started it). Based on the space/time continuum, something that takes no time - takes no space.

 

We believe that G'd is actively involved with the creation each and every second. Take, for example, a rock. Rocks do nothing - they just sit and will continue to sit until a force greater than gravity is exerted upon the rock. Then the rock moves. The rock will continue to move until that force is exhausted.

Likewise, there was nothing before creation. Nothing does nothing. The Almighty exerted a creative force upon the nothing making it a something. That something is a something for as long as Hashem keeps that force enclothed into the nothing.

Aristotle would maintain that G'd exerted that force a long time ago and stepped back. Jews believe that Hashem is Almighty. Hashem cannot step back as that would limit Hashem.

All the surveys seem to show that belief in God is high among Americans of all ethnic groups and religions except for Jews. Perhaps it is because we Jews historically have been trained to be sceptical and questioning. The same scepticism that Abraham had for idolatry, according to our legends, we – ironically – now have for belief in God. Perhaps Jewish belief is a function of higher education. The same surveys indicate that belief in God declines in direct proportion to educational achievement. That is to say, those with advanced degrees tend to characterize themselves as those with weaker beliefs than those without. Since Jews tend to be high academic achievers, we can see the results.

 

A few observations are in order. First, some people have almost in innate religious capacity. Some neuroscientists today have argued that human beings are hard-wired for belief, although it is not uniformly manifested across the population. Even those people who deny any strong belief in God will, in times of stress, call on divine assistance. (Thus the old saw: there are no atheists in fox-holes.”) Second, people are hardly ever convinced by argument to believe in God. Since the Middle Ages many European thinkers believed that God’s existence could be demonstrated by logical argument and, once presented with the evidence, doubters would have no choice but to believe. Even the Midrash (cf. Louis Ginzberg, Legends of the Jews, Vol. 1, p.193) asserts that Abraham engaged in these kinds of polemics. But today, the idea of using reason to convince the head to accept God when the heart refuses has all but been abandoned. Third, the single greatest obstacle to monotheistic belief is the problem of evil.  That the God we claim to exist is good and all powerful and yet evil is real and persists is a dilemma requiring either the denial that God is all good or that God is all powerful. In either case, the God that remains is lessened and allegiance to that God is questionable. After the Sho’ah – unimaginable evil - the dilemma is even sharper. Fourth, Judaism has maintained that practice trumps belief. That is to say, what counts is how we behave, not what we believe. Thus, the rabbis imagined God saying; “Would that they [meaning Israel] had forsaken Me and observed My Torah…” (Lamentations Rabbah, Introduction). On this view, belief in Judaism remains an open question. But practice is essential and necessary. Consequently, many more books are published today on Jewish practice than on Jewish belief. Lastly, some authorities have simply made belief in God a command rather than an option. Nahmanides, for example, in his commentary to Deuteronomy 6:4, sees no need to explain how to come to belief but only demand that one believes.

 

With these observations, I would suggest a heavy dose of Heschel. Rabbi Abraham Joshua Heschel (d. 1972) has written the single most important book on the subject in the modern period: Man’s Quest for God. It would be an injustice for me to even try to capture the stylistic beauty of his prose. But his main idea is easily captured: belief in God is a consequence of standing in awe at the world in which we live. When one feels exposed to a power greater than oneself, one is on the way to God. When one feels a longing for meaning, one begins a search for God. When one’s soul aspires to greater heights, one is living under the influence of God. Ultimately, these are the aspects of belief.