On Monday morning, throngs of students slowly made their way back to their weekly routines, their thoughts filled with a sense of nostalgia for the past weekend and anxieties for the upcoming last few days of classes. These thoughts, and others like them, are the daily norm. We accept them for what they are and rarely question where they come from. 
Our daily consciousness is the sole force that gives rise to what makes up everything we see and feel and think, but where does it come from? We all share the daily experience of “reality” and we accept it, yet neuroscientists today have very little idea of how it happens.
How does something inanimate and material such as the human brain give rise to subjective reality and emotions such as anxiety and nostalgia? For a while this question was strictly in the realm of philosophy, where there was a divide based on whether or not the mind is something entirely separate from the body. This mind-body dualism was most notably proposed by the French philosopher René Descartes.
Descartes posited that the mind—and thus subjective conscious experience—actually originates from an immaterial substance he called “res cogitans,” Latin for thinking thing. This substance allows for conscious thoughts and decision making, and exists somewhere outside the physical world we are so familiar with and on which all observational science is based.  
This view, however, is opposed today by many neuroscientists who identify as physicalists, believing that consciousness comes from highly organized normal matter.
This different approach turns out to be exceedingly difficult.  Explaining how subjective experience arises from normal matter is so difficult, in fact, that philosophers have dubbed it the “hard” problem. In the past decade, however, the science of consciousness is quickly gaining a legitimate scientific grounding.
This past week, hundreds of the world’s leading experts in consciousness studies gathered in Arizona for the largest conference on the subject. It is here where many scientists and philosophers hope for a significant lead in tackling the “hard” problem. That lead may finally have come to fruition.
Acclaimed MIT physicist, Max Tegmark, is widely known for his work on cosmology, but he recently released a paper that takes a completely different look at what consciousness might be. He supposes that consciousness can be modeled as a state of matter. Although this sounds quite fanciful at first, he gives an interesting and rigorous argument for his novel approach.
Tegmark contends that states of consciousness must obey a set of mathematical rules similar to the rules that govern varying states of matter. Just as ice turns to water under certain conditions, different levels of consciousness vary from one state to another. Approaching the problem in this way allows physicists and neuroscientists to start making progress towards a quantitative approach to consciousness.
For years, neuroscientists have agreed that consciousness must arise from certain parameters such as the processing of information in an integrated way. Now, Tegmark believes that this information processing can be categorized more specifically and will soon be able to be treated in a mathematically rigorous way.
Tegmark’s model, as with all models of consciousness, is still very speculative. Will there ever be a practical physical model for the nature of consciousness, or is this question outside the realm of the observational science that we know today?  
Regardless, understanding how the human brain functions is at the frontier of modern science and will push developments in neuroscience through the next century.