It all began in pure harmony; an infinite number of dimensions with an infinite amount of energy oscillating between them, all contained in an infinitely small amount of space. Then, due to the probabilistic nature of the movement of energy, the oscillations quivered in a slightly different way causing the waveform to cancel out, or destroy, some dimensions. Finite amounts of energy got trapped within the still existing dimensions causing them to expand or to collapse. With finite energy in a finite amount of space the forces of nature as we know them today started to cause interactions between the different pockets of energy. Soon particles were created and the universe continued to expand and cool down to such a degree that some of these particles started to stick to one another forming atoms. All the atoms formed a large hot cloud of gas that slowly reached a critical density collapsing in on itself forming the first stars completely made up of hydrogen and helium. Inside these stars was a reaction equivalent to the reaction in a hydrogen bomb, called fusion, which slams atomic nuclei together forming new atoms and releasing a lot of energy in the form of light and a few massive particles. These stars eventually burned up all of their fuel, and by doing so reduced their mass, and therefore their gravity, and they exploded. The explosion released all of these new atoms that had been created by fusion, which dispersed among the rest of the universe over billions of years and collided into each other forming new molecules. Soon new stars started forming and around them were a cloud of gas that had the new atoms and molecules within. These heavier atoms and molecules began to clump together as smaller less dense clumps of matter than the stars and they eventually coalesced into planets. Among a few of the new elements created were carbon, nitrogen, and oxygen, and when combined in various patterns (with several other types of atoms also) these atoms created the molecules that now comprise life as we know it, these molecules are called organic molecules.
Life was quick in the making compared with the time line of the universe. As the earth cooled down water started to collect on the surface as liquid rather than just as a gas in the atmosphere. Many of the organic molecules got stuck to rocks in tide pools, especially molecules called nucleic acids that easily stuck to lime rock. Waves crashed on the shores and brought in more nucleic acids that bound strongly to the others on the rocks forming chains of these different nucleic acids. Eventually a chain formed that was capable of twisting and bending in such a way as to trap other nucleic acids very easily and link them to one another. Long strands of these started forming across the entire planet and then suddenly something miraculous happened: one of the randomly linked together sets of nucleic acids was capable of linking other nucleic acids together in almost the exact same order as itself. In other words, it could reproduce itself. After billions and billions of copies were made, many with slight mutations from the original (which then caused a massive multiplication of this new form), there was something that resembled life: a chain of nucleic acids that could reproduce itself trapped within the confines of a bubble of oil. Not only could it reproduce the chain of nucleic acids it also happened to collect more oil from its surroundings that helped maintain the bubble. As time wore on these became what we now know as bacteria.
As bacteria grew and changed over time, fighting for resources in different areas, new organisms started to develop from these founders. Due to the process of evolution, animals, plants, fungus, protozoans, and different types of bacteria formed and invaded almost all areas of the planet. The dinosaurs came and went. Saber toothed tigers, six ton sloths, and enormous birds, then dominated the planet, but most notably in the history of our planet humans also evolved.
The physical forces between energy in multi-dimensions form particles, those particles form molecules, those molecules link together to form life, but how then can the interaction of molecules of life explain human emotion? The brain is made up many cells called neurons. There are neurons throughout the body also that can take a stimulation and send a signal to the brain as to what that stimulation was. The eye is a good example, it has many specialized neurons in it that are called rods and cones that change form when light with enough energy hits it. When this happens it causes a cascade of events to unfold that end with an electrical signal being passed down the length of the neuron. When the electrical signal gets to the end of the neuron that neuron then emits millions small molecules, called neurotransmitters, that cause other neurons in the vicinity to send another electrical signal, eventually the signals end in different parts of the brain, and sometimes that part of the brain interprets the signal and sends a new one back out to the muscles throughout the rest of the body. Sometimes it takes several stimulations to activate the neuron to produce a signal. The more stimulation that the neuron gets the easier it becomes to then stimulate it again. This is why it takes around eight repetitions in order for the brain to commit something to long-term memory. To explain emotion and thought in general take for example a child at a young age who's brain may have committed the memory of a close relationship with the mother to long-term memory as being a good stimulation. This has allowed the brain to interpret close relationships with people as being a benefit for the person and therefore a good memory, and good memories are to be sought after. Of course there are many different ways in which having people other than the mother or father interact with the child, or even adult, can form lasting memories that the brain interprets as “to be sought after”. Once the object, or person, or sensation, etc. if found or achieved, the brain reinforces itself thus making it easier to signal these “feelings”. This is what is called an emotion, and, being that it is now Valentine’s Day, this is how we can explain the feeling of love.
Love it of hate it, this extremely basic introduction to the workings of life and the universe is what happens... Well, basically. I actually made up a lot of how the universe was created, and I made very poor generalizations of how life developed and especially how the brain works, but the point is clear: we are a miracle of happenstance. A chemical and physical reality that is capable of realizing itself and forming relations, emotions, and complex thought. Incredible.
Here is a little quote I found in a book on my shelf entitled, This Book Will Change Your Life:
There is 1 chance in 140 trillion that the Earth should exist.
There is 1 chance in 795 billion that life should have evolved on Earth.
There is 1 chance in 89 billion that life should have evolved into mankind.
There is 1 chance in 12 billion that mankind should have created the alphabet and thus civilization.
There is 1 chance in 6 billion that your parents should have ever met and got together.
There is 1 chance in 90 million that you should have been the lucky sperm that fertilized your mother’s egg.
Overall you’re pretty lucky to be here. Today remember that and show some cosmic humility.