What is the deal with "instant" Karma?

DukeZhou, and those interested,

Is there validity to the concept of immediate or "instant karma" in a Buddhist context?

...was asked.

On a level of materialism, outwardly appearance, that what science merely observes, it might look as reasonable, but in terms of effects on experiance level, there is neither a linear nor a instant pattern to be found.

To understand the nondeterministic law of kamma, it's useful to give it a deeper read.

• The Seeds of Karma - 21 QUESTIONS ON KARMA & REBIRTH
• Suttas and works on kamma
• Kamma and the Ending of Kamma
• "Kamma" (Study Guide)

And it is not so, as suggested in an answer here, that a deed has a share instantly, later and much later in terms of the law of kamma. It's either this or that.

Generally "be careful", since

"The [precise working out of the] results of kamma... is unconjecturable that is not to be conjectured about, that would bring madness & vexation to anyone who conjectured about them." (AN 4.77)

...

Is there a distinct term for this type of intra-life cause and effect?

...was asked: Probably materialism or cosmology would be the therm for such views.

[Note: This is a gift of Dhamma, not meant for commercial purpose or other kinds of low wordily gains by means of trade and exchange]

Buddha talked about Immediate results of karma often, for example, if remember correctly, King Pasenadi Kosala (or could be someone else) asked Buddha what were the right here right now for giving. Buddha said, givers are generally loved by others, their good reputation spread, enter congregation without fear (confidence) , etc. Another one I can remember when king Ajatashatru asked Buddha what would be the gain for someone enter a holy life. IMO, King Ajatashatru was not much of a philosopher or a scholar but a warrior. Any deep difficult answer would have flown above him. SO Buddha gave him simple here and now gains for entering a holy life such as exempt from tax, exempt from military services, etc. This is an example of how Buddha would evaluate his audience before he gave an answer.

The term you are looking for is kamma-vipaka (karma-result). It is the result of a very rare and poorly understood causal relationship (vipaka-paccaya) between past action and future result. First of all, it must be said that we suffer plenty from poor judgement, ignorance, and unfortunate circumstances that there is no need to consider this unusual caused relationship. It is important to not confuse it with usual process of learning in which we make sense of experience through an unconscious mental decision-making (that constitutes a form of mental action or karma) called sankhara (that results in a learned disposition also called sankhara). Having learned to make sense of things in a particular way, we act in a particular way, make mistakes in a particular way, and suffer in a particular way. Eventually, we learn to avoid suffering. This kind of learning is not kamma-vipaka.

Kamma-vipaka type of learning involves one’s own Bodhicitta when we happen to perform an action that is exceptionally harmful or beneficial without consciously appreciating its extreme nature. The classical example is that of Moggallāna, a major disciple of the Buddha, who had killed his parents in a previous lifetime and suffered an extremely painful death (he was killed by robbers), even though he had the psychic power (siddhi) to escape that death. He (unconsciously) allowed himself the painful death in order to unlearn his belief that killing his parents was justified (at the time). Even though he undoubtedly had understandable reasons at the time, his Bodhicitta realized how profoundly harmful it was to his parents. According to Theravadin psychology, he could have mitigated the harm to his parents by sincerely apologizing to them for his mistake, but, of course, had no opportunity to do so. (On another level of awareness, he apologized to his parents by allowing himself the pain. Hence, the act of allowing himself to experience such pain was a profound act of compassion.) Conversely, a person who performed exceptionally beneficial action in a previous lifetime may be exceptionally “lucky” or happy in this lifetime.

The scriptures (AN 6.63) say there are three results of kamma: (i) instant; (ii) at a later time; (iii) at a further later time.

For example, a person drinks a lot of alcohol. The three results of this kamma are: (i) immediate pleasure; (ii) a headache or feeling sick the next day; (iii) craving for alcohol in the future.