Solomon wrote, “Whoso keepeth the commandment shall feel no evil thing: and a wise man’s heart discerneth both time and judgment” (Eccl. 8:5). In this article we continue our discussion of the nature of time.

One of the more interesting subjects with regard to time is speculation regarding the possibility of traveling through time. One might wonder why a page normally dedicated to religious topics would discuss something as implausible as time travel, but it will afford us an opportunity to highlight certain characteristics of time that have a bearing on our main subject, the nature of time.

Time travel is a frequent theme of science fiction novels and movies, however few believe that it might be possible to travel from one moment in time to another other than what we know to occur normally, i.e., sequential travel from one moment in time to the next in a forward direction. There are nevertheless some interesting theories regarding space and time that differ from our common conception of time.

The reason most reject notions about time travel is that time travel would involve numerous contradictions usually called “time paradoxes.” This refers to logical consequences of conflicts that could or might occur if one were to travel back or even forward through time. Whether one calls these conflicts “contradictions” or “paradoxes” I suppose depends on one’s point of view. On the one hand these conflicts contradict what we believe to be the nature of reality, but some might say that our view of the nature of reality is at fault and that therefore these conflicts are merely paradoxes deriving from our misperception of reality.

Be that as it may there are conflicts between the notion of time travel and what we believe to be facts of nature.

One conflict that has been presented many times is with reference to the time traveller who travels back in time to meet his grandfather as a young man. In the course of events the time traveller kills his grandfather before his grandfather has had any children. Obviously if the grandfather dies before he has any children, then neither does he have any grandchildren. Logically if he had no grandchildren, his grandson could not kill him.

A similar conflict can be presented with travel into the future. In this case a young time traveler travels into future. At this stage in his life he has not yet married, and he has no children, but in the future he happens to meet his son. In the course of these events the future son kills the time traveller thus preventing him to return to the present where he can marry and have children. Logically since the traveller did not live long enough to have children, he could not have met his son in the future, and he then could not have been killed by his son.

Science fiction stories struggle with “paradoxes” such as these in their efforts to present a coherent story line. For example some will put a time traveller in a “time bubble” where he cannot be influenced by changes in the past. (That would take care of the first paradox, but not the second.) Others postulate alternate time lines where not only can anything can happen, but where anything that can happen does happen with one time line going in one direction and another going in another for every possible alternative achievable. In one line for example the grandson kills his grandfather, and in another he does not. To that you would have to add a timeline in which after killing his grandfather he ceases to exist, and another in which after killing his grandfather he continues to exist. The postulate is absurd of course, but it makes for interesting mind puzzles.

The reason these contradictions exist has to do with the nature of time. We can put all moments of time from its beginning to its end in three broad categories: past, present and future. The past refers to all events which have already taken place. The future refers to events that have not yet taken place, but which will occur in their time. Finally the present refers to a moving dividing line between the past and the future constantly moving away from the past and toward the future. It is on that dividing line that events actually occur.

Now let’s consider some other differences between these categories. The events of the past are set in time meaning that the events are facts of history. We can speak of past events in propositional statements that have a truth value. For example the statement, “President John F. Kennedy was shot by a lone gunman,” is either true or false. We may not be able to say which it is, but we know it is one or the other, and nothing now can be done to change that fact.

On the other hand with the exception of preordained events the events of the future cannot be called facts, and not just because they haven’t happened, but because they may not happen. Unless we live in a fatalistic universe in which everything is fixed, the events of the future are dependent on numerous choices and possibilities. Tomorrow I plan to drive to worship with the Church of Christ at Richwood, but it would be wrong to say that it is a fact that I will do so. It would be wrong not because it would necessarily be false, but because statements of fact about the future are meaningless until those “facts” become facts. Many things could happen to prevent me from that choice, and it is even yet possible that I could change my mind and do otherwise. We even learn in scripture the foolishness of making definite statements about what will be (cf. Jas. 4:13-15).

The one exception to this is with regard to preordained events, or events that have been prophesied by God. God’s statements of events that are to be are as certain as events that have been. For example when God promised that the Lord will come in judgment against the world (1 Thess. 5:1-7), the fact of that coming is as certain as the fact of the Lord’s first advent. Peter wrote, “But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day” (2 Pet. 3:8). The passing of time makes no difference to God; his word is sure.

Other than that it is easy to see the differences between the nature of time-past and the nature of time-future. We can say that the past is fixed. Once an event has occurred, no matter how we might try, the act cannot be undone. In contrast the future is fluid. It will be what we make of it. One might have lived wickedly as a youth. As ashamed as he might be of his past, he cannot erase those acts. But it is possible for that same person to change his life so that his future becomes a life of service to God.

The time to make those changes according to God’s word is the present. Paul wrote, “We then, as workers together with him, beseech you also that ye receive not the grace of God in vain. (For he saith, I have heard thee in a time accepted, and in the day of salvation have I succoured thee: behold, now is the accepted time; behold, now is the day of salvation.) By using the word “now” Paul identified the present as the time that we have to make changes in our lives. We cannot go into the past to undo the wrongs that we have done, and the future is unavailable unto us until it becomes the present. If we ever hope to change our lives to right in God’s sight, we need to determine to make that change today! Tomorrow may never be.