Final answer:
Psychologists faced challenges in scientifically investigating consciousness, including the complexity of the subconscious and the difficulty in explaining our awareness of being aware. Empiricism also had limitations in accounting for non-sensory knowledge.
Step-by-step explanation:
One of the basic problems that many psychologists saw with attempting to scientifically investigate consciousness was the uncertainty and complexity of the human subconscious. Psychologists like Sigmund Freud and Carl Jung suggested that there were aspects of the human mind that were beyond our control or direct knowledge. Additionally, the nature of consciousness itself posed a challenge, as it was difficult to explain our awareness of being aware. Another problem stemmed from the limitations of empiricism, as it struggled to account for forms of knowledge that did not relate to the senses.