In a linear conception of time, the future is the portion of the timeline that is still to occur, i.e. the place in space-time where lie all events that still have not occurred. In this sense the future is opposed to the past (the set of moments and events that have already occurred before) and the present (the set of events that are occurring now).
The future always had a very special place in philosophy and, in general, in the humanmind because a huge part of human life needs at least a forecast of events that are to occur. It is perhaps possible to argue that the evolution of the human brain is in great part an evolution in cognitive abilities necessary to forecast the future, i.e. abstract imagination, logic and induction. Imagination permits us to “see” a plausible model of a given situation without effectively observing it in practice (therefore mitigating risks). Logical reasoning allows one to predict inevitable consequences of actions and situations, and therefore gives useful information about future events. Induction permits the association of a cause with consequences, a fundamental notion for every forecast of future time. Such abilities in getting at least glimpses about what is going to happen probably were tremendous forces in the evolution of mankind.
Despite these cognitive instruments for the comprehension of future, the stochastic nature of many natural and social processes made of the forecasting of future a long-sought aim for people of almost all historic ages and cultures. Figures pretending to see the future, like a prophet or a diviner enjoyed great consideration and even social importance in many past and even present communities. Whole pseudo-sciences, like astrology or cheiromancy originated with the aim of forecasting futures. Much of physical science too can be read as an attempt to make quantitative and objective predictions about events.