Stithaprajna  (Man of Steadfast  wisdom) is  the one who has acquired Spiritual Intelligence or Jnaana.  It is the one thing that makes you who are. This Intelligence is not acquired by pursuing studies through secular education but by personal efforts called Sadhana. Bhagavad Gita says “Sraddhaavaan labhate Jnaanam”—one who has faith attains Spiritual Intelligence or Knowledge. This Knowledge is not about the world we live in or the worlds we are trying to explore but that of Supreme Spirit called Brahman in Sanskrit.

But what is Sraddha translated often as faith and repeated at several places in different contexts in Gita and Upanishads?

Śraddha is a broad concept which has no direct English relative or equivalent. Besides faith, it could also mean confidence, and loyalty.  The teacher Ammachi describes it as the "constant alertness arising from Love", and when choosing a single word to translate it into English, has used "awareness".  Other writers have also described the concept with emphasis on the intersection of faith and mindfulness, and it has been translated in this vein with words such as "diligence”. Sri Aurobindo describes Śraddhā as "the soul's belief in the Divine's existence, wisdom, power, love and grace."  
Mr. Braunstein, a writer and his girl-friend photographer Sam Wriggles have decided to quit their jobs and explore what Sraddha means to different people around the country. The pair has conducted 62 interviews around the country meeting teachers, writers, Hindu Yogis, orthodox Jews, Buddhist Monks, Inter-faith priests, activists Lawyers, as well as people they have randomly encountered on the streets. Their search for the project “Searching for Sraddha” continues. How many of the Hindu Americans are so serious to study our scriptures, digest and propagate them for world benefit? It is much easier to build temples and run them efficiently with attractive festival celebrations and rituals! You can very well imagine how much more effort is needed to search for Stithaprajna? Yet I have made an honest attempt in this discourse.

It is very difficult to answer the question on Sraddha if one refuses to turn inwards and realize the Self within which is the basic thinking in Upanishads (Sraddha in the Self).   Sraddha cannot be dismissed by the simple translation of faith or devotion. It is conviction, determination, devotion, dedication and submission of the will all combined.  I believe this applies to all religions! My understanding of Sraddha in Bhagavad Gita appearing in several contexts is as follows:

Lord Krishna says in Gita the individual who holds firm faith, ardent devotion and determination attains Jnaana (knowledge of Supreme Spirit)--Sraddhaavaan labhate Jnaanam.  The meaning of the word Sraddha has been pronounced and revealed in many ways by Bhagawan.  Sraddha is indeed the basis of spiritual life. Revelation of the Supreme is really difficult without ardent faith, love and reverence. This knowledge is the mature fruit of devotional service, and when one is situated in transcendental knowledge, he does not need to search for elsewhere, for he enjoys peace within himself. Living in the essential nature of the self is indeed living in perfect peace.  Sraddha is the ardent aspiration of the embodied soul for the grace and blessing of the Supreme soul. It is the most sincere form of reverence arising from the deepest levels of the being. Sraddha is an unwavering, most sincere and ardent form of faith which enables all the inner beauties of Supreme-self to be revealed to the individual. It is like going into the most intimate and honest relationship with the Supreme-soul, which gives strength and inner integrity. Sraddha originates at the heart-centre by consciously living in the awareness of the Divine and gradually takes hold of the entire being. Sraddha is indeed the dynamic force that nourishes the spiritual ideals. It illuminates the understanding of the scriptural knowledge and changes into integral wisdom. Sraddha strengthens the love and devotion, purifies the thoughts, unfolds the inner capacities and sanctifies –the entire attitude towards life.
One should really go deep into Upanishads to find out deeper meanings of words like Sraddha, Jnaana, Stithaprajna   etc., based on the context.  Taittareeya Upanishad says a charity should be given with Sraddha--Gifts should be given with Faith, and it is not acceptable if not done so.  Pranaahuti (Offering food to God) mantras begin each mantra with the word Sraddha. In society faith is generally understood as some idea to be swallowed without questioning or inquiry.  Shankara says that to judge and understand rightly the full import of the advice of the teachers and the depth of the declarations in the sacred text-books and, thereafter, to struggle in our thoughts and activities constantly to attune ourselves to these intellectual judgements, is called Faith. This is not a simple faith but religious resolve faith.

Sankara defines Sraddha in his hymn in Viveka Choodaamani as follows:

Saastrasya guruvaakyasyasatya-buddhya-avadhaaranaa |
Saa Sraddhaa kathitaa sadbhiryaya vastu upalabhyate  || 25 ||

That by which one understands the exact import of scriptures as well as the pregnant words of advice of the preceptor is called Sraddha by the wise. By this alone Reality becomes manifestly clear.
Sraddha is a qualification found necessary in a spiritual aspirant. “Perhaps no other spiritual term has been so badly mauled by the priest class and so profitably polluted by the laity in Hinduism” says swami Chinmayananda. This is an essential prerequisite for anyone trying to master the truth of the scriptures. We all need certain amount of Sraddha even in our daily life.

Sanathan Dharma makes it possible for everyone to pursue their faith and achieve the same benefit regardless of what they believe. The ability to respect such devotion and validate their efforts in pursuit is unique in Hindu society. It will always be enigmatic for the western materialistic framework of reference who will find it lunatic to pursue something based on faith. For person dealing with demoralized people, I know how hard it is to develop faith in anything.

Daniel Gilbert shows that a wandering mind is not a happy mind. People spend 46.9 percent of their waking hours thinking about something other than what they’re doing, and this mind-wandering typically makes them unhappy… “Mind-wandering is an excellent predictor of people’s happiness,” Killings Worth says. “In fact, how often our minds leave the present and where they tend to go is a better predictor of our happiness than the activities in which we are engaged.”… Time-lag analyses conducted by the researchers suggested that their subjects’ mind-wandering was generally the cause, not the consequence, of their unhappiness.

What these Western authors are talking about is physical happiness necessary for healthy living Ayurveda also suggests “Laughing Exercise” as a pre-requisite to Yoga and Meditation to balance Kapha, Vaata and Pitthaa contributing to healthy and long living. But Vedanta describes two kinds of happiness Sreyas and Preyas.  Sreyas is inward happiness and leads to Eternal bliss making human spiritual life good leading to liberation while Preyas makes our living pleasant to lead a healthy physical life. Bhagavad Gita which reflects the Upanishadic thoughts of Kathopanishad often mentions about Sreyas and Preyas.  Its real difference and deeper meaning can be better understood by the following mantras in Kathopanishad:

Sreyascha preyascha manushyametah  tau sam -pareetya vivinakti dheerah |
Sreyo hi dheero abhi preyasoe vrineete preyo mando yogakshemaad vrineete ||

Both the good and the pleasant approach the mortal man; the wise examines them thoroughly and discriminates between the two; the wise man prefers the good to the pleasant, but the ignorant man chooses the pleasant for the sake of this physical body through avarice and attachment.

Sthithaprajnya   is translated in English as man of steadfast wisdom.  Arjuna inquires   Lord Krishna about the characteristic of such a person who becomes enlightened and who is firmly established in the consciousness of the transcendental awareness in Chapter two, Sankhya Yoga, A Way of Discrimination in Bhagavad Gita.  Our scripture considers one who has gained spiritual wisdom and gained wealth of spiritual education as Stithaprajna. Stithaprajna remains undisturbed with his mind focused on Brahman called Brahma-jnaanaam.

Sthitaprajnasya Kaa bhaashaa  samaadhi stasya Kesava |
 Sthitadheeh kim prabhaasheta  kimaaseeta vrajeta Kim || 2-54||

What is the definition, O Kesava (Krishna or Vishnu) of a man of steady wisdom absorbed in contemplation?  How does a steady man of steady wisdom talk, how does he sit, and how does he walk?

Bhagawaan says:

Prajahaati yadaa kaamaan sarvaan paartha manogataan |
Aatmanyevaatmanaa tushtah sthitaprajnyastadochyate || 2-55 ||

When a man gives up all desires of the mind, O Partha, and himself delights in his Self then he is said to be a man of steady wisdom.

Dhukeshu anidvignamanaah sukheshu  vigatasprihah |
veetaraagabhayakrodhah sthitadheer muniruchyate || 2-56 ||

He, who is unperturbed in misery and free from desires amidst pleasures, who is devoid of all attachments, fear and anger—that sage is said to be “Sthitadheeh”.  

Yah sarvatraan abhisnehastat praapya  subhaasubham  | 
Naabhi nandati  na dveshti tasya prajnyaa pratishthitaa  || 2-57 ||

He who is free from affection everywhere, and who is not elated by getting whatever good or troubled by whatever bad neither welcomes nor hates them, has a steady mind.

Yadaa samharate chaayam koormo -angaaneeva sarvasah |
Indriyaaneen –indriyaarthebhyah tasya prajnyaa pratishthitaa || 2-58 ||

When a person completely withdraws his senses from the sense-objects, even as a tortoise its limbs, then his wisdom is steady.

Vishayaa vinivartante niraahaarasya dehinah |
Rasavarjam raso-apyasya param drishtvaa nivartate || 2-59 ||

From an abstemious embodied being (man) sense objects fall-off, but not the relish for them; but even this relish of the man of steady wisdom ceases when that Supreme Being is realized.

Yatatoe hyaapi Kaunteya purushasya vipaschitah |
Indriyaani  pramaatheeni  haranti prasabham  manah || 2-60 ||

The turbulent senses, O son of Kunti, forcibly lead astray the mind of even the struggling wise person
.
Dhyaayato vishayaan pumsah sangas teshu upajaayate |
Sangaat  sanjaayate kaamah kaamaat krodho abhijaayate || 2-62 ||

Krodaad bhavati sammohah sammohaat smriti-vibhramah |
Smriti-bhramsaad buddhinaaso buddhinaasaat pranasyati || 2-64|| 

For a person thinking of the sense-objects there grows an attachment for them; from attachment arises desire, from desire results anger, from anger results delusion, from delusion results confusion of memory, from confusion of memory results destruction of intelligence and from destruction of intelligence he perishes.

Taani sarvaani samyamya  yukta aaseeta matparah |
Vase hi yasyendriyaani tasya prajnyaa pratishthitaa || 2-61||

Controlling all the senses, the self-controlled person should sit to meditate on the Lord. Verily, his wisdom is steady, whose senses are under control.

Sthithaprajnya is one who is firmly established in the prajnaana--the knowledge of Supreme Self. Jnaana means knowledge, prajnaana means the knowledge of the transcendental Self. The word intelligence and wisdom may appear synonymous but the two words differ in their meanings.  According to scriptures wisdom stands for Dhee and intelligence for Buddhi.  Dhee means cultured intelligence. When Buddhi stays connected with the transcendental Self it transforms into dhee and progressively Medha and Prajnaana.  It is the faculty of intuition.  It is the purest manifestation of the Self. The indwelling consciousness evolves and expresses itself at various levels. These are known by different names as the different states of inner awareness. The individual who is firmly grounded in the knowledge of the Transcendental Self is called Sthithaprajnya.  

“When a person learns to withdraw the senses from sense objects as a tortoise retracts its limbs inside the shell in times of danger and it cannot be forced to put its limbs out again except when the trouble is over, then the lamp of knowledge becomes lighted and one perceives the self-effulgent Supreme Being within. Mind can never be fully trusted. The wise always keep vigilance over the mind. It can even mislead a Self-realized person” says Mahabharata. The human mind is ever ready to deceive and play tricks. Therefore, discipline, constant vigilance and sincere practices are needed.  It is the very nature of mind to go to lower objects of enjoyment as it is the nature of water to flow downwards. The grace of God can make the mind go towards higher objects as Sun’s rays lift the water.

Our Gaayatri mantra says dheemahi ,  which means let us meditate on dhee—the steadfast wisdom, the indwelling Transcendental Consciousness. Let us live in the awareness of the Supreme Lord in order to be blessed with Prajnaana-the knowledge of transcendental Self. Transcendental Self is Brahman says Mahavakya of Upanishad “Prajnaanam Brahma”— Self is Brahman.  

We may sometimes have doubt what about desire for knowledge itself? The desire for knowledge, devotion and Moksha cannot be classed as desires, because they are higher or noble desires.  One should first replace the lower desires with higher desires and then renounce the highest desire also and become absolutely free. It is said that the highest freedom is the freedom from becoming free as explained by Sharada Devi.  Bhagawaan says in another context one should attain the status of Gunaateetaa  state where one should even get rid of Sattva Guna  even, a state of Nirvana or nothingness to reach Supreme Brahman. Gunaateeta and Sthitaprajnya are the states in which one attains prajnana which helps in the process of merging with Brahman.  Bhagavadgita says one should go beyond these states to become one with Brahman. 

Adveshtaa sarvabhootaanaam maitrah karuna eva cha |
Nirmamoe nirahankaarah samadhukhasukhaah kshamee || 12-13 ||

Santushthah satatam  yogee  yataatmaa dhridhanischayah  |
Mayyarpita manoe bhuddhir yo madbhaktah sa may priyah || 12-14 ||

Non-envious, friendly and compassionate towards all beings, free from ideas of possession and ego-awareness, sympathetic in pain and pleasure, forgiving , always contented, contemplative, self-controlled, of firm conviction with one’s mind dedicated to the Supreme--such a devotee is dear to the Lord.

Friendliness is a positive feeling of disinterested love and regard. Compassion is directed to those who are suffering and also towards those who feel enmity towards one.  Same in pain and pleasure status comes by eliminating thoughts of desire and aversion. A contented man is always peaceful. Restrained in thoughts, desires and impulses and firm in resolve are the same as Sthitaprajnya. Thoughts relate to Mind process (manas) while the resolves relate to Intelligence-process (Buddhi).  

Yasminnoedvijate lokoe lokoennoedvijate   cha yah |
Harshaamarshabhayodvegair muktoe yah sa cha may priyah  || 12- 15 ||

He by whom the people are not disturbed and whom the people do not disturb, he is indeed dear to the Supreme Being, free as he is from joy, impatience, fear and anxiety.

People are not scared, troubled or made unhappy by one who is absorbed in contemplation on the Supreme Being.  Such a person would have assured all creatures of his tender protection. That person is not scared, or troubled or made unhappy by the people around him also, for he does not care for anything as he is focused on God and is convinced that all things happen to him because of the will of the Supreme Being. Joy comes from things one likes to obtain. Fear comes from loss of life, hurt from enemies, robbers, wild animals, etc.  Anxiety is caused by an agitated state of mind.  Worry results from depression. On who is focused on Supreme is not affected by these factors.

Anapekshah sachirdaksha udaaseenoe gatavyathah |
Sarvaarambha-parityaagee yoe madbhaktah sa may priyah || 12--16 ||

Yoe na hrishyati  na dveshti na sochati na kaankshati |
Subhaasubha-parityaagee  bhaktimaan-yah sa may priyah || 12-17 ||

Samah satrau cha mitre cha tathaa maanaapamaanayoeh  |
Seetoshna-sukhaduhkehshu samah sanga-vivarjitah || 12—18 ||

ulyaanindaa-stutir-maunee santushtoe yena kenachit |
Aniketah sthiramtih-bhktimaan may priyoe narah  ||12—19||

He who has no expectations whatsoever; who is pure in body and mind; competent in his work; indifferent towards fruits of action; devoid of worries; and non-involved in all actions that are not indicated for him, that are selfish in intent, and are puerile and purposeless; who is neither overjoyed nor hateful; who neither regrets nor longs for anything; and who lays aside both auspicious and inauspicious undertakings; who is the same to friends and foes alike; whose equanimity is not disturbed by honor or infamy;  who looks upon heat and cold, happiness and misery as all the same; who is indifferent to blame or Praise; and content with whatever comes  his way,  not rooted in anything; and with a steadfast mind—such a devotee is dear to the Supreme Being.

These slokas refer to the outlook and attitudes of a Yoga practitioner while dealing with the world around him.   One, who is keen on liberation, must cultivate these qualities as effective tools for the path described as dharmyaamritam in the next sloka. Dharma here means what supports one, namely the Supreme Being and an approach to it is dharmya or Dharma sadhanaa. This in turn is Muktisaadhana or Liberation which is referred to as Amrita meaning imperishable.

Ye tu dharmyaamritam idam yathoktam paryupaaasate |
Sraddadhaanaa matparamaa bhakaas te ateeva may priyah || 12-20 ||

But those faithful devotees, who set the Supreme Being as their goal and sincerely develop above mentioned nectar of moral values become very dear to the Supreme Being (and attain Liberation.)
“We hear of an important disciple of Socrates in Aristippus (435 – 366 BC) of Cyrene, a Greek colony in present-day Libya. To him the goal of life was to seek pleasure by adapting circumstances to oneself and by maintaining proper control over both adversity and prosperity. He lived a life of equal disposition to pain and pleasure. Whether insulted wildly or praised grossly he remained equally calm. Thus he was truly a Stithaprajna (person having a steady intellect) as described in Gīta 2.56. And his life was a demonstration of the teachings in verses 2.38, 2.45, 5.20, 5.21, etc. of Gīta, which exhort us to desist from getting dejected at the face of adversities and elated too much at fortune” says Dr. Kartikeyan speaking on Ancient Western Philosophy. Ancient Western Philosophy is thus often based on Hindu Wisdom from Gita which in turn derives its philosophy from  Vedas and Upanishads though projected as a battle-field emergency document to guide the frustrated  and confused mind of Arjuna.

By the Veda Mantra Asato maa sadgamaya, Tamaso maa jyotirgamaya Mrityor maa   Amritam gamaya (Lead us from ignorance to Knowledge, from Darkness to Light and from Death to Immortality) we probably aspire for the status of Stithaprajnya for final integration with Paramaatman!
Bhagavad Gita often dwells in pairs of opposites like happiness and misery, hot and cold, hatred and love, Sattva and Rajas etc. The opposite of Sthithaprajnya is Chanchal Buddhi and Chapala Buddhi (Wavering Mind; Desire oriented Mind). Once has to over-come these negative tendencies, attain the status of Sthitaprjnya to march towards the goal of Jeevanmukta in this very life if possible or in fewer births exhausting one’s Karmaphalas.