Final answer:
Consciousness is described as a range of experiences regarding our awareness of internal and external stimuli, varying from full wakefulness to deep sleep. It illustrates our subjective perception of the world, influenced by biological rhythms and can be altered through various means such as sleep stages, drugs, or meditation.
Step-by-step explanation:
The author describes consciousness as our awareness of both internal and external stimuli, illustrating its multifaceted nature. Internal stimuli refer to the feelings within us such as pain or hunger, while external stimuli encompass what we perceive through our senses, like seeing sunlight or hearing voices.
Christof Koch emphasizes that consciousness is made up of our personal experiences, which are subjectively perceived and thus unique to each individual. For instance, the pain from a toothache or a tune stuck in one's head are both examples of conscious experiences that make up our reality.
Different states of consciousness vary from full awareness to deep sleep; even when fully awake, our awareness of the environment can fluctuate, as in instances of daydreaming. Biological rhythms play a critical role in our states of consciousness, particularly in regulating our sleep-wake cycle.
These various states of consciousness are further explored through the lens of biological processes and how they impact our psychological behavior.
Altered states of consciousness include changes experienced during sleep, as well as due to various physiological or pharmacological factors like drugs, hypnosis, or meditation. These states have a profound impact on our perceptions and experience of our surroundings and our inner selves, thereby modifying the continuum of consciousness.