Some of this argument is only provided for depth and clarity, though it is often blatantly obvious. I advise one to skip over the parts that already make sense to you.

Perceptions are unreliable:

• Perceptions are based on sensation and analysis. Sensation and analysis are neurological functions that are capable of being unreliable. This is easily represented by people who have neurological disorders, but ultimately a possibility for anyone. As they are neurological functions, which determine the reality we know, we can never be certain whether or not the are reliable.
• People very often perceive things differently than one another. This happens because based on where one is during a certain event, or how are brain interprets stimuli, sensations that deal with the event may vary. Also, previous experiences somewhat determine how we perceive the world, and everyone has different experiences. After the fact, there is usually one more widely accepted view of something, and one perception is usually closer to this conclusion than others. It is known to happen that someone will perceive something to have happened that didn't really happen because they had limited information. Since we cannot know everything, we can not be certain our perception is correct.

Memory is unreliable:

• Memory has three main neurological processes: recording, storing, and retrieving.
• Recording is based on perception, which is unreliable. Storage is most often incomplete, merely saving bits of information in pieces and sometimes loses or scatters important information, and is thus unreliable. Retrieval collects scattered pieces of information and (as anyone who has studied psychology of memory will remember) can be influenced to remember things differently than they actually happen, and is therefore unreliable.

For these reasons, attaining certainty is improbable.

We cannot be absolutely certain that what we perceive or what we remember is true. However, we can make assumptions of reality based on how likely something is to be true. The more likely something is to be true, the more reliable an assumption is to be.

Example: It is logical to assume that if I flip a coin and it lands somewhere flat that it will land on either one side or the other. (Based on my perceptions, every time I have executed this experiment this hypothesis has been true 100% of the time. Based on pure logic, there are two possibilities: it will either land on one of its sides or it will land on its edge; however, the theoretical probability of a coin that spins through the air to land in such a way that it will fall directly on its side after settling is incredibly small, though possible. Given that I trust my perception on this issue the combined theoretical probability that my hypothesis will be correct is approximately 99.9999999999%, making it logical to assume my hypothesis is correct)

Second Example: It is not logical to assume the same coin will land on one particular side in the same scenario. (The experimental data and the logical deduction provides an approximate probability of 49.99999999999%, which is not enough to make an assumption.)

When it comes to a theological discussion, probability can be applied directly to the origin of the universe. One can accept various explanations, but the most simple and well-founded explanations are these: either the universe came from nothingness (which is theoretically impossible), or the universe was created by a divine force. However, it is commonly overlooked that if the universe cannot come from nothing then neither can a divine force, therefore both scenarios are theoretically impossible. This means one can assume they have equal probability of being correct, and for the purposes of this discussion we can say they each have about a 50% chance.

Still overlooked is the probability that the divine force ("God" as some would refer to it) is as people view it is less likely:

• Chance of the previously mentioned divine force still existing: 0.00000000001%
• Chance of the divine force being at all cognitive: 0.000001%
• Chance of the divine force caring about humanity, or Earth at all for that matter: 0.0000000001%
• Chance of the divine force having intentions that coincide with the well being of humanity: 10%
• Chance of the divine force being omniscient: 0.0000000000000000001%
• Chance of the divine force being omnipotent: 0.0000000000000000000000001%
• Chance of the divine force being fully understood and interpretted perfectly through his "prophets": 0.00000001%

Overall chance of the divine force "God" truly being how people think "He" is: approximately one in a google. (that's really really small).

Actually, it is just as likely that "God" is a cruel bastard that just wants people to suffer.

Overall chance of the universe originated in the chaos of spontaneous combustion: approximately 49.99999999%

The point is, though it's quite possible that some divine force created reality is just as likely that it came from nothingness, but all that means is a force which we do not fully understand created our universe. Assuming that there is a "God" as people tend to view him is pure ludicrous.