Think about the taste of coffee, the warmth of the sun on your skin, or the feeling of happiness when you see a friend. These are all experiences. Consciousness is this state of having experiences. It’s your personal, private movie of the world, complete with sensations, thoughts, and emotions. Without it, you wouldn't be 'you' in any meaningful sense.

Scientists and philosophers often break it down into a few key parts. One is wakefulness—the difference between being asleep and being awake. Another is awareness, which includes both your awareness of the world around you (sights, sounds) and your awareness of your internal world (your thoughts, feelings, and sense of self). It’s the feeling that there is a 'someone' inside who is experiencing everything.

People have been thinking about consciousness for thousands of years. Ancient Greek philosophers like Plato believed in a soul that was separate from the body. This idea of a non-physical mind or soul inhabiting a physical body has been incredibly influential.

In the 17th century, French philosopher René Descartes famously argued for a clear split between the mind (a thinking, non-physical thing) and the body (a physical machine). This created what's known as the mind-body problem: if the mind and body are fundamentally different, how do they interact? How does a feeling of sadness (mind) cause you to cry (body)?

For much of the 20th century, especially in psychology, the study of consciousness was pushed aside. Behaviorists argued that we should only study observable behavior, not the unseeable inner workings of the mind. But in the last few decades, thanks to advances in brain science and a renewed philosophical interest, consciousness has made a major comeback as a serious topic of study.

Studying consciousness presents a unique challenge. Philosopher David Chalmers split this challenge into two parts: the 'easy problems' and the 'hard problem'.

The 'easy problems' aren't actually easy, but they are solvable with the standard methods of neuroscience. They involve figuring out how the brain processes information. For instance, how do we distinguish between different colors? How does the brain control our actions? How do we focus our attention? These are questions about functions and mechanisms.

The 'hard problem' is explaining why all that information processing feels like anything at all. Why do we have subjective, qualitative experiences? There's nothing in the physics of light waves and neurons that says the color red must look the way it does. This inner, subjective quality of an experience is what philosophers call 'qualia'.

Imagine trying to describe the color red to someone who has been blind from birth. You can explain the physics of light wavelengths and how the eye's cone cells react. That’s the easy problem. But you can never convey the actual experience of seeing red. That’s the hard problem.

Today, both science and philosophy are essential for tackling the mystery of consciousness. They ask different kinds of questions but work together.

Neuroscientists hunt for the Neural Correlates of Consciousness (NCCs). The idea is to find the minimum brain activity that is required for a specific conscious experience. For example, by showing a person different images and using fMRI to watch their brain, scientists can pinpoint which areas become active when the person becomes aware of seeing a face versus a house.

Philosophers, on the other hand, explore the conceptual landscape. They craft thought experiments to test the limits of our understanding and clarify what a scientific theory of consciousness would need to explain. The hard problem itself is a philosophical contribution that has guided scientific research.

Ultimately, a full understanding of consciousness will likely require a deep integration of both scientific data and philosophical insight. It’s a journey that touches on the very core of who we are.