From a Kantian perspective, our cognition is limited to phenomena, the way things appear to us, shaped by the categories and structures of the mind (such as space, time, and causality). Kant held that we can speculate about the ding an sich, but we can never know it directly because our knowledge is always mediated by our senses and conceptual frameworks. So while it may exist independently, its nature is fundamentally inaccessible to us as human beings.