Moments in time
Accordingly, distinct and duration-less present moments of experience have to be connected to create phenomenal continuity over time, this conception of time essentially being a cinematographic metaphor. A present moment, in this line of thought, is like a mathematical point on a continuum, an isolated and duration-less instant in time. This puzzle is based on the assumption that an observer perceives static snapshots of the world that somehow have to be integrated to form unified experiences over time (Kelly, 2005). If perception is really limited to a present moment then we cannot perceive motion, change, the passage of time (Le Poidevin, 2007). Taken together, phenomenal consciousness consists of an island of presence in the continuous flow of time related to what is happening right now (Metzinger, 2004).Ī debate exists in the philosophical literature surrounding a presumed puzzle of how it is possible to have a temporal experience, to perceive duration, when our experiences are confined to the present moment. The experience of the passage of time constitutes itself through an event that is first anticipated, then experienced and eventually remembered. The unity of the present is related to our sense of nowness. Phenomenological analysis has pointed to these two complementary (or seemingly paradoxical) aspects of experience: the feeling of a present moment and the passage of time (James, 1890, chapter XIV Husserl, 1928). Conscious experience is not static and unchanging the passage of time is often described by a stream or a flow. This temporal aspect of phenomenal consciousness – its nowness – is inherent in all our experiences: I see, hear, feel, and think at the present moment (Metzinger, 2004 Droege, 2009). The contents of consciousness are phenomenally present – now. On a third level of integration, continuity of experience is enabled by working memory in the range of multiple seconds allowing the maintenance of cognitive operations and emotional feelings, leading to mental presence, a temporal window of an individual’s experienced presence. It has been suggested that this segmental processing mechanism creates temporal windows that provide a logistical basis for conscious representation and the experience of nowness. On a second level, an experienced moment, which is based on temporal integration of up to a few seconds, has been reported in many qualitatively different experiments in perception and action. Below a certain threshold temporal order is not perceived, individual events are processed as co-temporal. On an elementary level, one can identify a functional moment, a basic temporal building block of perception in the range of milliseconds that defines simultaneity and succession. Therefore, empirical evidence from psychophysics and neuropsychology on these distinct temporal processing levels is presented and discussed within philosophical conceptualizations of time experience. In recent literature concerning the philosophy and neuroscience of consciousness these separate temporal processing levels are not always precisely distinguished. Successive events are fused into units forming a unitary experience or “psychological present.” Studies have identified several temporal integration levels on different time scales which are fundamental for our understanding of behavior and subjective experience. It has been suggested that perception and action can be understood as evolving in temporal epochs or sequential processing units.