Document Type : Research Paper


1 Ph.D. student of philosophy) logic( at Tarbiat Modares University, Tehran, Iran.(Corresponding author)

2 Associate Professor of philosophy at Tarbiat Modares University, Tehran, Iran.


Future Contingency has been an old debate between philosophers throughout history. On one hand, Aristotle thinks events of the future happen contingently. On the other hand, Diodorus believes what happens in the future is now determined. Diodorus has presented an argument for determinism based on a few premises. Logicians and philosophers try to avoid determinism by denying the first premise of Diodorus, which is the necessity of the past. However, they only regard a qualified version of this premise based on the medieval argument for determinism while some other philosophers consider this premise in a general way. A new argument shall be presented in this paper for determinism similar to the medieval one based on the general version of the premise which is not rejected by systems which reject the medieval argument. This flaw originates in a few properties of the branching model for time. We shall show what this property is and how it would be possible to resolve the problem this property creates.


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