Philosophers like Gottfried Leibniz and Immanuel Kant hold that space and time "do not exist in and of themselves, but ... are the product of the way we represent things", because we can know objects only as they appear to us.
St. Augustine of Hippo called time a “distention” of the mind (Confessions 11.26) in which the past is based on memory, the present based on attention, and the future based on expectation. A similar view was expressed by Henri Bergson who said that time was neither a thing, nor a mental construct, but was Duration, that comprised creativity and memory that lead to reality.
Greek philosopher, Antiphon, in his chief work, On Truth wrote: "Time is not a reality (hypostasis), but a concept (noêma) or a measure (metron)." Parmenides maintained that time, motion, and change was illusionary. The Buddhist thought also considers time to be an illusion.