Most generally, the past is a term used to indicate the totality of events which occurred before a given point in time. The past is contrasted with and defined by the present

Present

Present is a time that is neither past nor future.Present may also refer to:- Time and timing :* Present tense, the grammatical tense of a verb* Before Present, radiocarbon dates relative to AD 1950* Presenting, a medical term* Presenteeism...

 and the future

Future

The future is the indefinite time period after the present. Its arrival is considered inevitable due to the existence of time and the laws of physics. Due to the nature of the reality and the unavoidability of the future, everything that currently exists and will exist is temporary and will come...

. The concept of the past is derived from the linear fashion in which human observers experience time

Time

Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....

, and is accessed through memory

Memory

In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....

 and recollection

Recollection

Recall in memory refers to the retrieval of events or information from the past. Along with encoding and storage, it is one of the three core processes of memory. There are three main types of recall: free recall, cued recall and serial recall...

. In addition, human beings have recorded the past

Recorded history

Recorded history is the period in history of the world after prehistory. It has been written down using language, or recorded using other means of communication. It starts around the 4th millennium BC, with the invention of writing.-Historical accounts:...

 since the advent of written language.