“They are more than just fleeting flights of subjectivity that pass through our minds and are gone.  Thought forms are ideas on steroids.” -  Gus diZerega

In occult and mystical writings, it is often asserted that “thoughts are things.” The Western occult tradition views the cosmos as multitude of levels or “planes” of  reality. The physical level that constitutes the world of our ordinary experience is the densest and “lowest” plane of this hierarchy. The other levels are normally invisible to human perception.

The so-called mental plane, which is several levels above the physical, consists of a highly refined spirit/matter/energy substance. When we think, and particularly when we hold a concentrated thought, we create, even if only temporarily a mental “object” that takes on an existence outside our mind. These mental creations, emerging out of mental plane substance, are thoughtforms. The effective agents constructing and maintaining such forms are devas (angels).

In the occult view, the thoughtforms become subtle but nevertheless powerful agents that, at least potentially, affect events on the physical level.  For instance, if one persistently visualizes a certain desired state of affairs, thoughtforms are created that exert a subtle, “magnetic” influence in that direction similar to visualization.

A thoughtform is the equivalent concept to a tulpa  (Indian Buddhist texts for  any unreal, illusory or mind created apparition) but within the Western occult tradition. The Western understanding is believed by some to have originated as an interpretation of the Tibetan concept. Its concept is related to the Western philosophy and practice of magic.

"A thought-form is the result of two types of energy:

• That emanating in the first instance from the Ego on abstract levels.
• That originating in a secondary sense from the man on the physical plane through the medium of the brain." (A Treatise on Cosmic Fire, p. 958)

 "All activity of every kind is the result:

a. Of thought-forms built consciously or unconsciously.
b. Of self-initiated thought-forms or of the effect of the thought-forms of others.
c. Of responsiveness to one's own inner impulses, or of responsiveness to the impulses of others, and therefore to group thought-forms." (A Treatise on Cosmic Fire, p. 977)

Creation of a Thought-form is easy. Many do it every day without even realizing it. A Thought-form can be an individual entity, even semi-self-aware, or it can be very short lived and dependent upon its creator for sustenance. If you perform daily positive affirmations, you are creating a limited Thought-form which attempts to bring about your will.

A thought form is a structured energy form created to carry out the specific task for which it has been programmed. A Thought-form may leave your person to achieve its assigned task before returning to nothingness, while another may remain with you, drawing energy from you until its task is complete.

Thought-forms can be put to any use you have the imagination to devise. The more complex the task, the more “intelligence” the thought-form may need to complete it. A complex Thought-form is more likely to develop self-awareness as par for course as it meets the challenges you set for it. You may create one Thought-form to be a personal protector, and another to “fetch” you things.

There are positive and negative Thought-forms. Depending upon your intent and emotional state of mind when you create a Thought-form, it may be negative and destructive or positive and helpful. Obviously, negative Thought-forms are more likely to get out of control and possible come back to haunt you, literally. A negative Thought-form or “Vampiric” Thought-form may return to you after you set its task, to feed on your energies and cause you harm.

A Thought-form can be created in any image you wish. Use creative visualization to form one that best suits your intention or purpose for it. You may feel most comfortable with angels or fairies, dragons or unicorns, robots or aliens. Or you may design something completely unique for some specific task. Design your Thought-forms in accord with your aesthetics as well as their usage.

Once you have visualized your Thought-form as completely as you feel you are capable, it is time to assign it its task. First tell it precisely and as specifically as you can what you want it to do. You can also make use of your spirit guides, asking them to help you relay your will to the entity you have created. In relaying your instructions to your Thought-form, also set parameters and limitations. Without limits, a Thought-form will not know when to stop working. This can become dangerous - as in the story of the Sorcerer’s Apprentice when the construct did not know when to stop bringing water and created a flood. You can tell your Thought-form both how to go about accomplishing its task and create tools for it to use as well. Though you may think something is obvious, don’t assume a Thought-form will have the same moral framework or common sense that you possess. If you want to prevent it from doing unintentional harm, tell it to complete its task without harming anyone or anything. Tell it to go back to nothingness when it has finished its task to prevent it from becoming a Vampiric entity afterward. – Angelfire.com

References:

Angels A-Z by Evelyn Dorothy Oliver and James R. Lewis  (Page 360)

A Treatise on Cosmic Fire – Alice A. Bailey

Wikipedia – Tulpa

http://www.angelfire.com/de/poetry/BOS/ThoughtForms.html