Full Idea
Augustine answers that for us to be aware of time it must exist only in the mind, …and the difference between past and future is just the difference between memory and anticipation.
Gist of Idea
To be aware of time it can only exist in the mind, as memory or anticipation
Source
report of Augustine (Confessions [c.398]) by Adrian Bardon - Brief History of the Philosophy of Time 1 'Augustine's'
Book Reference
Bardon,Adrian: 'Brief History of the Philosophy of Time' [OUP 2013], p.25
A Reaction
This is an extreme idealist view. Are we to say that the past consists only of what can be remembered, and the future only of what is anticipated? Absurd anti-realism, in my view. Where do his concepts come from, asks Le Poidevin.