Why is God invisible?

How do we know who God is or that He even exists? John Wisdom wrote a parable about an invisible gardener to illustrate the argument over God's existence. Two people return to a long neglected garden and to their surprise find some vigorous plants growing among the weeds. The believer says, "There must be a gardener whose been coming to take care of the plants. "The skeptic disbelieves and points to the weeds. They pitch their tents and watch, but they see no gardener. The believer eventually concludes that the gardener must be invisible, leaves no scent, and makes no sound. The skeptic asks how this differs from an imaginary gardener.

A real life example of this argument over God's existence was when astronaut John Glenn responded to Soviet cosmonaut Titov. Titov said he "saw neither angels or gods" while in orbit, and that he did not believe in God. A week later, John Glenn responded, "To look out at this kind of creation and not believe in God is to me impossible. It just strengthens my faith."

The physical characteristics of the universe to permit life are evidence for a Designer or Creator. The cosmic mass density terms for the expansion of the universe must be precise values for the universe to support life. This extreme fine-tuning of the mass density
see "Most Profound Fine-Tuning" in Hugh Ross, "Why I Believe in the Miracle of Divine Creation," editors Norman L. Geisler and Paul K. Hoffman, Why I Am a Christian: Leading Thinkers Explain Why They Believe (Grand Rapids, Mich.: Baker Books, 2001). Also, see http://www.reasons.org/resources/apologetics/index.shtml#design_in_the_universe
term must be within one part in 1060 and the space energy density within one part in 10120.One part in 1060 of the known universe is about one-tenth the size of a dime. Thus, the addition of one dime to the universe would throw off this fine-tuning and not allow for life.
A naturalistic attempt to resolve how something so improbable could happen uses the finite dimensions of the Big Bang universe to propose an infinite number of parallel non-overlapping universes or a multiverse.
See Max Tegmark, "Parallel Universes" Scientific American Magazine, May 2003.
With an undefined number of non-overlapping universes, they claim that our universe hit the jackpot and happen to be in the one with the right fine-tuned parameters to support life. The wish for a naturalistic explanation of the universe motivates proposing a multiverse explanation. However, one must redefine naturalistic to classify the multiverse theory as naturalistic. How can someone verify the existence of parallel universes mutually exclusive from our own?
Just after he published a book on the multiverse
Paul Davies, Cosmic Jackpot: Why Our Universe Is Just Right for Life, Orion Productions, 2007.
, Paul Davies apparently lost enough confidence in that theory to offer a new one. He proposes '' the universe has engineering its own bio-friendliness through a sort of feedback loop that operates in both directions in time.'
Paul Davies, Arizona State University, http://cosmos.asu.edu/. Also, see "Cosmic Log: Why is the universe bio-friendly? Is it intelligent design, or blind chance, or none of the above?" in http://cosmiclog.msnbc.msn.com/archive/2007/04/19/160480.aspx
From the naturalistic standpoint, this is a very egocentric view of the universe. From the religious standpoint, this is a pantheistic view of the universe. The naturalistic explanations for the existence of the universe without God are harder to believe than to accept that God created it.

Even when one accepts creation as the explanation for the origin of the universe, questions remain. "Why is God invisible?" What is the difference between an invisible God and an imaginary one? Can we know anything about God?

Much of our universe is also invisible. The universe is much larger than we can see. We continue to enlarge the amount of universe we see with better telescopes, and telescopes that sense the electromagnetic spectra not visible to our eyes. We haven't mapped every galaxy in our universe. Even what we have seen on other planets in our solar system is limited, much less planets in other solar systems.

Not only is the full extent of the macroscopic universe beyond our vision, but also the microscopic. We developed techniques such as electron microscopes and atomic force microscopes to view what is too small to see with visible light. We developed techniques for detecting subatomic particles, but have evidence that even smaller particles make up electrons, protons, and neutrons. Even an end to the microscopic world isn't in sight.

Besides the macroscopic and microscopic, the visible is insufficient to explain the physics of the Big Bang.
See "Extra-Dimensional Creation" in Hugh Ross, "Why I Believe in the Miracle of Divine Creation," editors Norman L. Geisler and Paul K. Hoffman, Why I Am a Christian : Leading Thinkers Explain Why They Believe (Grand Rapids, Mich.: Baker Books, 2001). 129. Also see Raphael Bousso and Joseph Polchinski, "Unified Field Theory: The String Theory Landscape," Scientific American, September 2004.
With the limitation of three spatial dimensions and time, gravity and quantum mechanics contradict each other. Ten dimensional string theory makes the two consistent. This theory adds six more dimensions to the familiar four dimensions. The Big Bang starts with ten rapidly expanding space-time dimensions, but after 10‑43 seconds, six of the ten dimensions stop expanding and remain at a radius of 10‑33 centimeters. This radius is much smaller than any known particle, and the time much shorter than any we measure. In fact, any known particle is closer in order of magnitude to the size of a visible particle than this radius. The highest known frequency of electromagnetic radiation (highest frequency gamma radiation) is near 1030 Hz or a period of 10-30 seconds. This corresponds to a wavelength of about 3 x 10-20 cm. Thus, the other six dimensions stopped expanding 10-13 times faster and within a radius 10-13 times smaller. While any physicist expects physics to expand and continue to become more refined, this does point to more than what appears to the senses.
The cause for the fine-tuning of cosmic density terms of the universe is at least 1097 more intelligent and powerful than humanity.
See "Most Profound Fine-Tuning in Hugh Ross, "Why I Believe in the Miracle of Divine Creation," editors Norman L. Geisler and Paul K. Hoffman, Why I Am a Christian : Leading Thinkers Explain Why They Believe (Grand Rapids, Mich.: Baker Books, 2001), p 133.
The estimated number of atoms in the know universe is about 1080. Such knowledge exceeds anything conceivable within the known universe and is independent of time and the dimensions of this universe to exist before it began. The dimension of time as we know it started with the Big Bang. The Entity responsible for creating our universe is beyond our understanding. Because He is separate from the dimensions of our universe, He is invisible to us. Since God's existence is independent of our physical world and He is too great for us to understand, how can we know anything about Him? Although God is beyond our reach, it doesn't mean God cannot make accommodations to communicate with us or that He doesn't interact with our world.
The characteristics of the universe point to a Creator, who exists outside the dimensions of our universe. While this gives us evidence of a Creator, this general revelation of God leaves Him as invisible and unreachable. However, since He had the ability to create the universe, He also has the ability to interact with it. While God is invisible to us, has He ever expressed who He is through particular people and historic events? While God is incomprehensible through the general, has He accommodated our understanding to express what He wants us to know about Himself? Has He given us special revelation, expressing Himself in the particular? This is the claim in the Biblical revelation.
Gary R. Habermas, Walter Bradley, and Winfried Corduan defend this claim in "Part 4: Why I Believe the Bible Is the Word of God," in Norman L. Geisler and Paul K. Hoffman, Why I Am a Christian : Leading Thinkers Explain Why They Believe (Grand Rapids, Mich.: Baker Books, 2001).

What is the best way for God to reveal Himself in terms we can understand? If God were to become human and live with us, then we could understand Him by how He lived. That is what God did as Jesus Christ.

Not only is much within our universe invisible. Much of who we are is invisible to the rest of humanity. Not only do we need to ask, "How can I know God?" but also, "How can I know who I am?" We cannot completely explain ourselves in terms of the physical world. While we continue to progress in neurology and explain more of the mind in terms of the brain, much of the mind eludes explaining and is the subject of debate. An inexplicable aspect of the mind is the ability to choose. One attempt to explain choice in terms of probability is parallel universes for each possible decision one can make. In another universe, the person makes the different decision and lives accordingly. While this parallel universe theory isn't as widely considered possible as the one explaining the fine-tuning of cosmic mass density, it points the same way to the problem with choice.

A practical aspect of the mind being invisible is the distinction between how a person appears to other people and the mind. It's easy to consider outward appearance as most important. This thinking disconnects actions from the mind, from thoughts, motives, and emotions. It leads to one acting out a part that may not reflect what one thinks or feels and doesn't reveal one's motives. The Scriptures reveal that God sees the inner person not just the external (1 Samuel 16:7). If a person wants to do wrong, but is forced to do right, is that person good? For a person to be good, he must want to be good. The book of Job deals with whether Job will do good for the sake of being good without receiving a reward for doing so. Even when it appears Job is about to die, while his wife and closest friends fail to encourage him, Job maintains his integrity (Job 2:6-10). Of his family and friends, Job alone passes the test and passes without even knowing he was tested (Job 42:7-10).

Learning self-motivation to do right, rather than needing external motivation, is an important purpose for our life. People are born with the instincts for self-preservation and reproduction, but those desires don't stop with self-preservation or reproduction. The desire remains to amass wealth beyond necessities. The desire remains to eat beyond the point of being healthy. Sexual attraction isn't restricted to husband and wife, and reproduction is seldom its primary motive. Violence far exceeds self-defense. People struggle with many desires, which have a purpose in their proper place, but motivate them to actions that neither satisfy their desires nor meet their purpose.

Rules and laws can help establish a standard for right, but they don't give someone the desire to do right. They don't even necessarily get someone to act in line with the purpose of the law. People may seek to evade the law without breaking it, or even break it in such a way to avoid the penalty.

While rewards and punishment are important methods for teaching small children, good parents desire for their children to be self-motivated. The most effective way for children to learn includes setting a good example. Similarly, God's most complete revelation of Himself is His becoming the man, Jesus Christ. As Jesus, God experienced all the same human desires we do, but lived as God wants us to live. He is the ultimate example of how to live.

However, Jesus' most important accomplishment was to pay the penalty for our sin (our falling short of good). God highly values this accomplishment, but we don't understand it well. As with goodness, God doesn't force this atoning gift upon us, we must accept it. God's atoning gift transforms our lifestyle from opposing God to cooperating with Him. God adopts us similar to how people adopt children. Just as a good parent seeks to direct a child towards moral goodness, God does the same with us. The goal is more than getting us to behave properly. It's to build good character. It's for us to behave properly because we want to behave that way.God has freed us from the penalty of sin to follow Him out of love rather than fear of punishment.

When we receive Christ's atonement, we also receive Christ, living within us through the Holy Spirit. The Spirit desires good and opposes our inborn selfish desires. The Spirit doesn't override our desires, but gives us ability to desire good. It's up to us to follow the desires of the Spirit and put aside selfish desires. Because selfishness can cloud our thinking, an external written source, the Bible, gives us a standard to test the spirits and distinguish which desires are consistent with God's will.

While God has communicated to us through the Bible, our primary means of communicating with God is prayer. Prayer is for our benefit because God already knows our thoughts, but prayer is more than meditation. God knows what we need better than we do, but often He wants us to ask. Prayer gives Him the opportunity to show Himself though His working in our lives. We must ask to recognize that work is His.

The sign God gave Moses so he would know God sent him was that he would bring Israel out of Egypt to worship God on the same mountain where God spoke to him (Exodus 3:12). Later when Moses was there with the people, he asked God to let him see Him (Exodus 33:17-18). God only allowed Moses to see His back (Exodus 33:19-23). We cannot see God's face, what He will do in the future. We seldom recognize what He is doing now. We best recognize God when we look back and see what He has done.

Note: I took this approach to answer the philosophical question, "Why is God invisible?" This is not how I would approach a systematic theology.