Tao Te Ching, The Art of War, The Book or Five Rings and I Ching all offer excellent principles.
These are what you need in self defence.

Scour your art for underlying precepts of body use, relationship and strategy.

Provocative behaviour will draw attention to yourself.
Wearing your martial arts costume, sweatshirt or lapel badge all call attention to what you do.
Similarly, macho behaviour only demonstrates an inner weakness. An insecurity. Your fear.

Keep your skills quiet and subtle. Avoid being noticed.

Optimal range is a necessary consideration in terms of health, and combat.
It is the degree of range that enables you to use your extension most effectively.
Considerations:

1. Ease
2. Root
3. Comfort
4. Strength
5. Stability
6. Movement
7. No leaning
8. Relaxation
9. No stretching
10. Maintain balance

When operating within your optimal range, your body is far stronger and more resilient.
It can adapt, change and move with ease and comfort.

Stretching the body is good when the purpose is exercise.
When lifting a heavy object or when engaged in combat, stretching in not a good idea.

The problem with stretching at the wrong time is that it puts stress on the body, reduces stability and prevents freedom of movement.
A stretched joint cannot rotate and turn comfortably.
It is not relaxed.
It is prone to injury.

The internal arts never advocate stretching in everyday life or combat.
The joints remain free and loose, heavy and dropped.

The internal arts teach the student to move the entire body towards the opponent, rather than stretch out the limbs.
Stretching is regarded as foolish:

1. It exposes the ribcage, armpit and torso
2. It makes the joints less resilient
3. It makes it easier for your balance to be taken
4. An opponent can avoid a strike more easily
5. The further out from the centre you reach, the less power you have

Rather than stretch, you step.

If you cannot employ optimal power at your current range, do something else.

Long, narrow stances are not combat stances. They were designed for performance.

The deep, horse stance is not for combat either. It is intended to build strength in the legs.

A realistic combat stance enables you to be pushed firmly from all sides without any loss of root.
It allows freedom of movement.
It keeps the joints and spine mobile and loose.

Find the stance that allows you to use your body in a smooth, natural, spontaneous fashion.
A stance that easily facilitates walking.

Partner work, form and other drills can teach students about reach and range.
Three useful solo training methods are easy to practice at home:

1. 3 tier wallbag
2. Striking post
3. Pushing peng (against a wall)

The wallbag ensures that your strikes are powerful and have no adverse feedback into your body.

Use a tree, column or doorframe as a striking post and practice stepping and striking.
With practice, you learn how much power you possess at what range, and begin to find the different ranges instinctively.

Pushing peng is about finding optimal alignment, relaxing and cultivating groundpath.
Virtually any posture from the form can be trained this way.

Ask your training partner to:

1. tug sharply on your wrist
2. kick your thighs and calves vigorously
3. push your torso from all sides
4. be awkward against your applications

Did you lose balance?
Did you need to tense-up or perform an action in order to compensate?

If your stability is lost or you lacked power, explore your stance, reach and range.

The key to getting stronger is to master the fundamentals.
Spend a lot of time just standing.
40 minutes once a week is great.
15 minutes a day is a must.

Moving qigong in its various forms will supplement standing, training the body to move in the correct way.
Form accomplishes the same.

Partner drills build up awareness and sensitivity.
The ability to affect another person.

A striking post or wallbag ensures that your strikes possess power, rather than just being empty.

The weakest part of any new starter is the mind.
Modern minds are lazy, distracted, eager for gratification and entertainment.

The calm, detached, logical, disciplined mind of a martial artist is very different to that of a 'consumer'.
We recognise that there is more to life than shopping, celebrity, fleeting fads and fancies.
Patience, tenacity, endurance... these develop a quiet strength.

We are not interested in pitting strength against strength.
Our aim is to evade strength, re-direct power and destabilise the attacker.

Instead of force against force, we circumvent.
We break the root.
We lead into emptiness.

You do not need to be immensely strong in the upper body.
The power will be coming from the ground, so stronger legs are more important.

Most people quit within a lesson or so, others within a year.
The hype surrounding modern tai chi leads new starters to have high ambitions and low commitment.

For some inexplicable reason new starters forget that using the body for hours at a time requires strength.
Combat necessitates concentration and stamina.

It is common to see new starters gasping for breath minutes after a melee exercise commences.
Their minds are reeling in confusion.
They are not breathing properly.
They are incredibly unfit.
Unprepared.

And yet these same people wonder why they are not being shown advanced-level skills...

The journey into self...

Taoism is concerned with the nature of our existence. It is not a religion in the common sense of that term.
It asks hard questions about our values, beliefs and perceptions.
It posits the possibility that much of our knowledge is based on cultural conditioning, rather than fact.

A serious journey into taoism will challenge the most ardent student.
There are no rituals, dogmas or practices to perform.
No worship.

The insights uncovered by your study will affect your everyday life.
Taoists try to appreciate, learn from and work with whatever happens in life, rather than impose order on a chaotic world.

Taking an unflinching look at who you are and how you live your life will go a long way to tempering your ego.
Taoism is not for people seeking a new 'lifestyle region'.
It is uncompromising.

As an off-shoot of taoism, zen also warrants some serious study.

Immersion in the way...

Mastering yourself is not so easy.
Taoism counsels you to remain quiet and anonymous, to avoid attracting attention.
You must become one with the tai chi, and one with everything around you.
The process refers to the ongoing loss of self and the immersion of your mind and body in tao:

1. No ego.
2. No opinions.
3. No aggression.
4. No attitude.
5. No pride.
6. No vanity.
7. No petty behaviour.
8. No cruelty.

Lose everything that stops you from being a pure, natural person.
Only when you have surrendered every thought, memory and pre-conception can you begin to feel humble and compassionate.
These qualities must be genuine, not artifice.

It may take a lifetime but it will be time well spent.

 Taoism furnished the basis for aesthetic ideals, zen made them practical.

(Kakuzo Okakura)

Why is the tao so valuable?

 Because it is everywhere,

 and everyone can use it.

 

 This is why those who seek

 will find,

 And those who reform

 will be forgiven;

 Why the good

 will be rewarded,

 And the thief who is cunning

 will escape.

 

 (Lao Tzu)

Our tai chi movements utilise three dimensions at all times:

1. Vertical
2. Horizontal
3. Forwards & backwards

Every posture, every movement, is a combination of these three dimensions.
It has to be. It is the physics. Width, height, length.

Certain body parts enable us to use three dimensions:

1. up & down, using hand and back
2. side-to-side, using the waist, hips and legs
3. movement between the feet

 Pick any tai chi exercise or movement and consider it in light of this.

Pushing is the action of moving something using the application of force.
Force requires something to push off; this is called resistance.
Resistance is the opposing force.

Tai chi never uses force against force, so it can only be applied when there is very little resistance.
We only ever apply 4 ounces of pressure.

Mastery

After a 20 year Master/disciple relationship, Peter Southwood awarded Sifu Waller 'Master' status in the Year of the Tiger.
He said that Sifu Waller should start wearing the red sash instead of black.
Peter Southwood felt that Sifu Waller qualified as a Tai Chi Master on the basis of the following accomplishments:

1. The 1300 page website giving unparalleled insight into tai chi
2. Exceptionally good shuai jiao, chin na, jing and form applications
3. His grasp of whole-body strength, how to cultivate it, refine it and teach it
4. His study of taoism and the Tai Chi Classics and his skill in infusing the art with the requisite principles
5. The production of a professional-quality syllabus, complete with logical, comprehensive grades, belts and assessment

The samurai must maintain his faith in his beliefs, even as the social or political climate shifts and alters. He must be patient, must act in a manner that may at times seem irrational or illogical, must resist the temptations of instant gratification, and must work towards fulfilling what may seem to be an impossible idea.

As a result, the samurai is often something of an outsider, a rebellious figure because he refuses to conform to the habits of the day.

(Takahiro Kitamura)  

Consider Newton's third law of motion: For every action there is an equal and opposite reaction.

The more force you apply, the more resistance you will encounter.
This is clearly counter-productive.

Slow, smooth, soft movements are a sure indicator of skill.

We take refuge in pride because we are afraid to tell the truth to ourselves.

 

 (Kakuzo Okakura) 

In order to fully understand the ramifications of the form movements, it can be quite useful to apply the form.
When a tai chi person possesses a poor sense of application, this tends to reflect their overall limited understanding of the art.
The form was designed with combat in mind.
If you lack the ability to use the form, what are you practicing?
What mistakes might you make?

Students often find form application to be exceedingly difficult because they lack the martial background and spatial awareness to see the possibilities within the form.
People sometimes import ideas from other martial arts, but these do not sit well with the form and lead to a singularly non-Chinese approach emerging.

A useful way to get a sense of potential form application is to train 2 person sets or drills.