Any Greek student is familiar with the basic idea of the perfect tense:  completed action.  The tense is used to describe (1) an action or process that has been completed and (2) has produced results that are still in effect at the time of writing.

When you try to analyze the meaning of a perfect tense more precisely, you should begin by asking, "Which aspect of the meaning is being emphasized here:  the completed action or the existing results?"

Sometimes the perfect tense is used primarily to emphasize the fact that some results are still in effect.  It is an especially strong way to stress the fact that something is.  This use is called an Intensive Perfect.  Whenever you look at the context of a perfect verb and find that you have a strong urge to translate it like a present tense, you are probably looking at an Intensive Perfect.  And you'll find that many versions of the New Testament will translate it as a present tense.

    Example:  Romans 14:23 -- "He who doubts is condemned" (perfect tense).

In other cases, the context will make it clear that the writer is using a perfect tense verb primarily to emphasize the completed action, rather than the existing results.  This doesn't mean that the results do not exist; it simply means that they are not highlighted.  This use is called a Consummative Perfect.  It is normally translated using the word "has" or "have."

    Example:  Acts 5:28 -- "You have filled Jerusalem with your teachings."

These two uses are mainly a difference of emphasis, and it is quite possible to find perfect verbs that put roughly equal emphasis on both the completed action and the enduring results.

Beyond these two primary uses, it is possible to find a few other shades of meaning in the use of perfect tense verbs.  For instance, the Dramatic Perfect is used to describe a fact in a vivid manner, even though smooth English demands that we render the verb as a simple past tense.

    Example:  Matthew 13:46 -- "He went and sold (perfect)all he had."

One grammarian describes the aorist tense in Greek as one that presents an event in summary, "viewed as a whole from the outside, without regard for the internal make-up of the occurrence" (Fanning, Verbal Aspect, quoted in Daniel Wallace, Greek Grammar Beyond the Basics). 

What does that mean in normal English?  Simply that a verb in the aorist tense describes an action without analyzing it further.  When John 3:16 says God loved the world, the aorist tense merely reports what God did.  It doesn't tell us when he started or when he finished (or whether he ever stopped).  It reports the bare fact.

You might compare it to the way I would describe a piece of fruit:  "This is an orange."  That's about all I can tell from an outside view.  If I peeled the orange and pulled the section apart, I could tell you a lot more about it.  I might be able to tell whether it was starting to get moldy, and make a guess about how long it had been sitting in the refrigerator.  

It's in this way that the aorist tense gives an "outside," unanalyzed view of an action.  It happened, and that's all you can prove, based merely on the aorist tense.

However, even though the aorist tense doesn't tear apart an action and analyze the details, Greek professors are perfectly to analyze the aorist verb!  By looking at the context of the word and thinking logically about the meaning, you can fine-tune your understanding and come to some more detailed conclusions about the action.

Here are some of the kinds of actions that might lie under the surface of an aorist verb.

1.    Constative Aorist -- the official description for an aorist that describes an action in its entirety.  This is the most foundational meaning of the aorist.

        Example:  John 2:20 -- "This temple was built in forty-six years."  The verb takes a 46-year process and wraps it up in a single package.  The emphasis is on the fact that it happened, not on how long it took.

2.    Ingressive Aorist -- an aorist that focuses on the beginning of an action. 

       Something similar happens in the imperfect tense as well (the inceptive imperfect).  What's the difference in meaning?  Usually the ingressive aorist describes the start of a new status (something that you are), while the inceptive imperfect is used to describe the start of a new action (something that you do).

      Example:  2 Corinthians 8:9 -- "For you he became poor."  Jesus entered into a state of poverty.

3.    Culminative Aorist -- an aorist that emphasizes the completion of an action, especially the results that flow from it.

     Example:  Philippians 4:11 -- "I have learned to be content."  Paul had gone through a learning process and had come to the point where he could claim to have learned the lesson.  A culminative aorist is often translated like a perfect tense (has learned instead of the more typical learned).

4.    Epistolary Aorist -- Sometimes the writer of a letter would put himself in the place of those who would eventually read his letter, and he would use the aorist tense to described something that had not yet happened.  At least it hadn't happened when he was writing the letter.  By the time the letter arrived at its destination, however, the act would be an accomplished fact -- so he uses aorist to describe it.

     Example:  Philippians 2:28 -- "I sent him then more quickly."  Paul was talking about Epaphroditus, whom he was sending back home to Philippi.  When Paul wrote the letter, Epaphroditus was still with him in Rome; he hadn't sent him anywhere.  But by the time the Philippians got the epistle, Epaphroditus would be there among them.  In fact, he probably carried the letter!

5.    Dramatic Aorist -- an aorist used to describe an action happening in the present, usually to emphasize its certainty.

     Example:  John 13:31 -- "Now is the Son of Man glorified."  Jesus makes this statement at the Last Supper, the night before His arrest and crucifixion.  The events culminating in His death were just beginning, yet John uses the aorist tense to describe the idea.  Most translations render "is glorified" in the present tense because the rules of English grammar demand that rendering.

6.    Prophetic Aorist -- an aorist used to describe a future event, usually to show that it is so certain that you can view it as already completed.

     Example:  Romans 8:30 -- "Them he also glorified."  This phrase occurs in a series of verbs describing the steps in salvation, from predestination to calling to justification.  These first three have already been accomplished in the life of a believer; the glorification is yet in the future.  But once God has begun the process, he will certainly finish it.  Thus the aorist tense is appropriate.