An idea to deal with the problem that we can apparently only be aware of what is present, and what is present must be momentary (otherwise it would include the future or past and not be all present), yet anything real must exist for at least some time: so how can we be aware of anything real, and of things as continuing in time?
Introduced by E. R. Clay and quoted by William James (1842-1910) in The Principles of Psychology (1901).
The specious present is a short period (various claims have been made by psychologists as to its length), allegedly presented to consciousness as all present at once, though in reality never more than one moment is present at once (hence the 'specious').
Our awareness of it, however, does take place all at once, being a single momentary act, or an element of a continuous series of such acts.
Objections to this include the view that the problem of generating our awareness of the passing of time from momentary experiences (whatever they are of) is a false one since such momentary experiences are a myth.
W James, The Principle of Psychology, 1 (1902), 609;
C W K Mundle, 'How Specious is the "Specious Present"?', Mind (1954)