my bad, perhaps i should say it is not guaranteed unless conditions are met. 

conditionality, karma and rebirth are inter-related, they cannot exist independently.

there is element of predictability. read sutta MN136. the buddha clearly expounded the teachings in the sutta whereby there are different states of rebirth one can take place in, given when certain conditions are there. only when certain conditions are met then only outcome can be guaranteed.

karma is a natural phenomena/process, which is not to be philosophized nor debate on whether it is true or untrue. it is experiential, and you can experience this phenomena from moment to moment if your mind is clear enough to see, then you'll understand.

the thought experiment (container with ants) you created does not even have any relation at all in proving/disproving the phenomena.
maybe you are wondering, how do i know i am guaranteed not to be reborn as an insect or other misery states? according to early scriptures, there are 31 planes of existence (https://www.accesstoinsight.org/ptf/dhamma/sagga/loka.html)
ant belongs to the animal realm, which is a woeful state of existence. you are only guaranteed not to be reborn in the 4 woeful realms only when you have the right causes and conditions. they can be found here: sota­patti­phala sutta (SN 55.55) , dutiyasariputta Sutta (SN 55.5), and https://www.accesstoinsight.org/lib/study/i...the_stream.html

In this post I want to explain the experiment to disprove karmic action.

The experiment is pretty simple.

Just collect 50 samples of living things. To avoid human morality issue, do it on ants.

Randomly split 50 ants of the sample into 25,25 and put them in two different containers.

Container A you spray insecticide on it. Container B you do not.

The outcome is pretty predictable. No matter how you choose to split the sample, ants in container A always ended up dead. That means irrespective of whatever their past lives, they are made to die. Those in container A are guaranteed to die, it does not matter what their past lives were.

Therefore karmic action cannot be guaranteed. The real cause of their death is actually the spray of insecticides on them. Their past lives have no part to play.

Just do the same thought experiment using human. Then you will see that karma is either untrue or useless.

yup, whether or not you subscribe to the believes of 'karma' & "rebirth', they are merely religious ideology. you will find your own version of Truth when you experience them personally. 

That means the believers are saying the ants were chosen were the resultant (re)action of their past deeds and this karma chain cannot be broken.

My question will be, when can a new karma chain be created ?

What is stopping one to say "I killed somebody because of my past deeds" and that's my karma ?

Isn't that renders karma a useless piece of explanation ?

I am just explaining the karma point. Only you're touching about ideology, religious war, and terror. You can continue to hurt people if you think karma is untrue. No one can stop you.

Only ignorant will claim certain thing is untrue. The universe is so huge. Anything is possible unless you visited the whole universe.

At least I won't become ignorant like you to claim certain things as untrue.

All the stars, planets and galaxies that can be seen today make up just 4 percent of the universe. The other 96 percent is made of stuff astronomers can't see, detect or even comprehend.

That's why it's silly to claim certain things to be untrue. The size of the universe is beyond imagination. How can you be sure no other human/Aliens on the other side?

I will only say based on my past experience, karma is likely to be true. I won't claim anything to be 100% true or proven to be a fact. Unlike TS already concluded it' to be untrue.

Based on a thought experiment is also very tiny compared to the universe. At least I said it's likely.

But ignorant like you like to make a conclusion without evidence to prove karma is untrue.

Actually we won't know the speed. It might just depend on Buddha to decide or he got to set how the system will do automatically. Karma can come quickly or slowly or carry to your next life. But what I noticed is those who bad to me really got karma only. Although the time could be different to receive it.

Just give a little example of my karma experience only. No force you to believe. Primary school got one gangster always beat and bullies me, a few months later his mother passed away.

I took gula2 from somewhere, went back home, accidentally canned food fall down and cut my legs much blood.

Gov fitnah n charged me and malicious prosecution. Then barang naik fallen and bijan and his gang all got charged and those involved got sued in court now by pastor wife.

Got 1 ktard silent stalker defamed me many years ago, straightaway his kids admitted hospital.

This is based on what I remember and important only. Karma is definitely real. Not happens yet does not mean it's not real. It's just a matter of time.

Think about deeply since you open this thread.

You are ignorant if you think your karma will only affect yourself alone.

I have heard people those guillotine executioner, their next life will suffer some kind of neck pain. I know you won't believe it. Just nerve problem rite...

He invited the whole class for her mother's funeral. The teacher arranged bus to his house. After the incident, his personality totally changed. No longer being a bully. You cannot imagine the sadness he had suffered for him to change completely. If you think it's fun, continue it.

The bully experienced the saddest moment of his life. Something precious which he lost it permanently.

Plant to bear fruits (effect) need all the natural conditions (causes) to be met, lack one of it, it won't bear. Everythings exist because of conditions are met at the right time, right place, right space...etc.

We do learn in each life but it is stored in our subconscious so that the next life, if we do learn it again, it will be very fast. 

Ever heard of  people who can speak foreign languages even though they never studied there?

Ever heard of child prodigy? I can give one million other examples.

LOL. I have been bitten by mosquitos a billion times in my life and I never have dengue or malaria.

You're just like saying that driving a car will kill you but I have driven my car for decades and I am still alive and never involved in a bad accident.

Okay. So
Causesation case 1;
You died because you did something bad and karma comes knocking.

Causesation case 2
You died because it was your time. Karma had 0 effect.

So, in the 2 cases  the cause was different, yes? You're still dead though.

If karma is true, then irrelevant whether a person believes it or not, it will still take effect.

Granted, if only relevant to a person if he believes it, and for those who don't, they can choose to live their own life accordingly