How to prove that thoughts exist?

Thoughts are transmitted by the spirits.  Spirits are separate elements. A human being during his/her lifetime is living with many spirits which have joined one by one since birth. They are knowledge, skills, feelings, emotions, interests and everything. These spirits are your consciousnesses and memories. Even thoughts are not your own. For example, when you want to take a decision on a subject, one after another the spirits think and you just listen, choose or reject the ideas which they transmit to your mind through your brain in the form of thoughts. These spirits always play game with each other to dominate you in a higher level. They have their own motivations. When they are same there is no problem at all but when they differ the problem starts. They expect that you must talk what they think, you must do what they ask to do and you must accept their thoughts. The interruption of word which is called as a slip of the tongue while you talk is caused by spirits.

Brain is just a media to connect the spirits to your mind. A mind is just a computer's mind. A mind is you. After the destruction of a computer completely you will not get it's mind. The same is the case with the human beings.  A human being doesn't have a spiritual body. Soul is nothing but an energy needed for the functionality of a body. It is not a spirit or anything else. A body's functionality is based on the auto mechanism.  After death all spirits which accompanied a person quit and go to different places searching new bodies. No one lives in any form after death. All human beings are just robots made of flesh and bones and toys of the spirits for their games.

A thought is like I love being a westerner or I love being Far Eastern where everything and everyone is equal because we are all Pagan unlike the opposite for Judaism Christianity and Islam.

What kind of question is this lol.

Ask someone to think of something and then have them describe it.

Suppose thoughts don't exist.

This leads to an reductio ad absurdum argument

Proof is a cognitive event. You must show something, physically or logically, that others can follow and which is compelling. It is therefore impossible to "prove" our emotions or our thoughts! They are invisible and not subject to logical inspection. That said, 500 years ago, Descartes was having the same idea, and ultimately realized that HE at least must exist because there he was thinking about existence. I THINK, he said, therefore I AM (exist).

By experiencing them, and by noting their effects. 

By inference from actions following them (except of course thoughtless reflex or instinctive actions).

Here is your proof !

Methinks you thought about your question, hence Descartes' "I think therefore I Am" (Christian version) for you may be "I think because I am," a question therefore of ontology first, epistemology second, with epistemology lifting ontology by epistemology's bootstraps; in classical physics, this is circular or infinite regress, "epistemological turtles all the way up."

The Mind is in its formations.  You might consider pursuing Dr. Henry Stapp's approach to thought as being both classical and quantum in Nature:  http://quantum-mind.co.uk/theories/henry-stapp/

Related:

The Path of the Higher Self;

Light Is a Living Spirit.