  Arguments of a far more empirical sort have challenged the causal status of meta-mental consciousness, at least in so far as its presence can be measured by the ability to report on one's mental state. Scientific evidence is claimed to show that consciousness of that sort is neither necessary for any type of mental ability nor does it occur early enough to act as a cause of the acts or processes typically thought to be its effects (Velmans 1991). According to those who make such arguments, the sorts of mental abilities that are typically thought to require consciousness can all be realized unconsciously in the absence of the supposedly required self-awareness.