Final answer:
Locke's view that our awareness is limited to sense data might lead to skepticism about the knowledge of an external world, as supported by Hume's empiricism, while responses by Kant and Moore offer different perspectives on overcoming skepticism.
Step-by-step explanation:
Supposing Locke is right that we are only ever directly aware of sense data, it could be argued that this does pose a challenge to knowing about external objects. Locke's view might lend itself to skepticism because if all knowledge is based on sense data, then how can one be sure that there is an external world beyond these perceptions? David Hume, a skeptic, further explored this notion by arguing that sense impressions, our most immediate form of perception, do not prove the existence of an external, independent reality. This viewpoint starkly contrasts with direct realism, which contends that one can have an unmediated perception of the external world, notwithstanding the possibility of deception via illusions or hallucinations.
Philosophers such as Kant attempted to address skepticism by arguing that while we can't know things in themselves, we do have knowledge structured by the categories of understanding, implying that knowledge is tied to the empirical world that we can experience. G. E. Moore challenged skepticism by asserting a common-sense approach, where the immediate recognition of hands, for instance, offers assurance of an external world without the need for further skepticism or proof.