Learning & Memory

Introduction

Nerve Impulses

Ion Channels

Synaptic Transmission

Learning - Overview

Pavlovian Type

Hebbian Type

Holographic Memory

Comprehension

Everyone can associate rain with dark cloud, but it requires Newton's ingenuity to associate the fall of apples with moon's motion, and Einstein's imagination to relate energy with mass by the equation, E = mc². As a matter of fact, most people possess the ability similar to what Newton and Einstein had: forming a theory to associate (explain) events already experienced by the brain. This ability is not limited to researchers in physical or biological sciences. A stock market trader, after years of experiences, can also form a theory to predict the up and down of the market. Of course, not every theory is correct. When a set of events can be associated by a theory, these events will become "reasonable" or "comprehensible" to the brain. If the theory is indeed correct, it will have the power to predict future events, like weather forecast.

The goal of biophysics is to associate biological phenomena with physical laws. Although many theoretical gaps remain to be filled, there are good reasons to believe that all biological processes can eventually be explained in terms of the properties of atoms and molecules. In physical chemistry, the properties of atoms and molecules have been able to be explained by quantum mechanics. In theoretical physics, an even more fundamental theory has been developed, which can unify all four fundamental forces (gravitational, electromagnetic, strong and weak nuclear forces). This "theory of everything" is known as the string theory.

A revolutionary discovery of the string theory is that the whole universe (called the "bulk universe") should have ten dimensions of space, instead of three dimensions (length, width and height). The reason why we perceive only three dimensions of space is because our matter and electromagnetic waves (photons) are confined in a sub-universe called the "braneworld". It is impossible for us to see anything outside our braneworld by light or other electromagnetic waves (more info). Imaging that there is a creature confined on a TV screen. He thought his world was two dimensional because he cannot see anything outside the TV screen. He does not know there is a three dimensional world with humans, animals, stars and other matter. The discovery that our braneworld is embedded in a higher dimensional bulk universe poses an interesting question: does the bulk universe contains a world with lives and other matter which are invisible to us? This invisible world could be the "spirit world" that many religious people believe it must exist.

How did our braneworld come to exist? Cosmological observations have strongly suggested that it started with a Big Bang about 13.7 billion years ago, but its cause is not known. According to physical laws, the only process that can create anything from vacuum is the quantum fluctuation. The Heisenberg's uncertainty principle allows energy to be created spontaneously and then vanish within a short time. The quantum fluctuation has been confirmed experimentally, but only for tiny particles with small amount of energy. Cosmologists assumed that the Big Bang was created by the quantum fluctuation. However, the Big Bang is a gigantic event which requires creation of huge amount of energy. The possibility for quantum fluctuation to create such an enormous energy is nearly zero.

In an article entitled "The String Theory and the Origin of God", an alternative scenario was proposed:

A spirit world was first created from vacuum in the bulk universe. The highly intelligent life (God) in the spirit world then created our braneworld.

The spirit world should obey physical laws, but its matter has entirely different properties than ours. The string theory has been able to explain why they are invisible to us (more info). The physical laws do allow creation of stable matter from vacuum without violating the energy conservation law and the formation of ordered structures in consistence with the thermodynamics laws (more info). With the string theory, it is possible to comprehend not only our braneworld, but also the spirit world.

What is the origin of the physical laws? We may never have answers to this question. We know our universe has something. Since something cannot come from nothing, certain things must be self existence (the aseity). In theology, God is assumed to be the aseity while in science physical laws are the aseity. If we can explain everything in terms of physical laws, we have reached the ultimate goal of science.