Plotinus (205-270), a neo-platonician philosopher, raised the issue of self-reference in a definition of time based on time, and said that this was a confusion between what is numbered (measured) and what numbers (measures). In contrast to Aristotle, he argued that time existed before Selleckchem SB939 number was applied to it.12 One should remember that, at the time of Plotinus, Christianity strongly influenced philosophy and science: Adam had committed Inhibitors,research,lifescience,medical a sin, and since then the soul of man was separated from God and thrown

out of eternity into temporality. Saint Augustine (354-430) says that there is no time outside of the soul. Here is the quotation that follows the epigraph: But, then, how is it that there are the two times, past and future, when Inhibitors,research,lifescience,medical even the past is now no longer and the future is now not yet? But if the present were always present, and did not pass into past time, it obviously would not be time but eternity. If, then, time present—if it be time—comes into existence only because it passes into time past, how can we say that even this is, since

the cause of its being is that it will cease to be? Thus, can we not truly say that, time is only as it tends toward nonbeing?13 This quotation follows the idealistic philosophy that, from Inhibitors,research,lifescience,medical Parmenides (~520—~455 BC) to Plato (~428—~348 BC), stands in opposition to the empiricism of Aristotle. As another illustration, Plato wrote that time is a moving image of eternity.14 If time only exists by and for the

soul, then what does one measure when speaking of time? Saint Augustine gives a clear answer: “I measure something in my memory which remains fixed.”15 He was the first to relate time to memory; much later, Dali did the same when he entitled his 1931 painting of soft watches, Inhibitors,research,lifescience,medical mentioned above, The Persistence of Memory; currently, the Inhibitors,research,lifescience,medical role of memory functions in relation to time is the theme of much research in neuroscience. The opposition between the phenomenological description of time using memory by Saint Augustine and the mechanistic explanation of Aristotle of time being the number of movement has never fully been solved in Western philosophy. The beginning of modern physics The materialist tradition also favors eternity in relation to time: atoms and the emptiness of the universe are infinite, uncreated, and imperishable. Time represents an illusion due to the appearance in consciousness of events that, in themselves, are accidental, according to Lucretius (~98—~55 Endocrine Reviews BC).16 Until the 17th century, one did not make the distinctions between three versions of time: time as an abstract number, time as it is measured in physics, and duration (a version of time as felt in our consciousness). Galileo (1564-1642), the founder of modern physics, considered the universe to be written in the language of mathematics—an idealistic idea opposite to Aristotle’s empirism—and saw the world as expressing an eternal order of things, that we can conceive, although we cannot feel them.