 But this passage is somewhat ambiguous. Here Descartes distinguishes (1) becoming aware of something, which apparently requires only a single thought, from (2) becoming aware that we were aware of something. Apparently, first-order awareness does not require a reflective act. And, while becoming aware that we were aware of something does require a reflective act, it does not require a distinct thought (and so the threatening regress is not problematic). But it’s not at all clear from this passage how the reflection could be built in to the original thought, especially since there appears to be a shift in tenses (the second awareness is temporally posterior to the initial awareness).