Six philosophical thoughts, most often called as   Ṣaḍ Darśanas of ancient India, are the help books to understand the different aspects of the comprehensive knowledge enshrined in the Vedas. These six Darśanas are not different from Vedas but are part and parcel of the long Vedic tradition of India. That is why these books are called Upāṅgas or Āstika (theistic) Darśanas, as they follow Vedas as authority. The philosophical thoughts developed other than these were called as Nāstika Darśanas, or those developed disregarding the guidelines of the Vedas. The terms Āstika and Nāstika denote admitting the authority of the Veda and discarding the same.

All six philosophical schools supplement each other. They deal with separate aspects of knowledge and creation. For instance, the Mīmānsā of Jaminī deals with karmakāṇḍa. Karmakāṇḍa represents creation as the karma of Brahman and karmas to be done by human beings for their pārmārthika (spiritual) elevation and laukika (material) upliftment and advancement. Thus, karmakāṇḍa of Mimānsā, on one side, deals with karmas that produce sāttvika sanskāras leading an individual towards divinity; on the other hand, it talks about the sankāras of material things for devising eco-friendly technologies for upliftment and advancement of human life at the laukika (mundane) level.

The Nyāya of Gautama deals with research methodology. It teaches all methods and techniques through which humans can attain true knowledge of material things, the cosmos, and Brahman.

The Vedānta of Vyasa deals with the supreme entity Brahman, the Nimitta Kāraṇa (efficient cause) of the whole creation and the Governor of the universe in the manifest and unmanifest state. This whole universe is governed by certain rules, which are nothing but the will of Brahman reflected as information in His cosmic mind called Prakṛti. This will of Brahman is also called a unified law or Ṛta, which is at work in the existing universe in diverse forms.   

The Vaiśeṣika of Kaṇāda deals with the physics and metaphysics of the existing universe. It divides padārthas (all entities of the visible and invisible world) into six categories: dravya (material and spiritual entity), guṇa (quality), karma (action/motion), sāmānya (generality), viśeṣa (individuality), and samavāya (inherence).

It explains and describes guṇa-dharmas (properties) of all six padārthas. When applied for beneficial use, knowledge of the properties of these padārthas (entities of the visible and invisible world) empowers us to improve the conditions of our mundane lives. The same understanding of the properties of material entities makes us realise their temporariness. It inspires us to self-realise and realise Brahman called Mokṣa, the prime objective of human life.

The Yogadarśana of Patañjali is a practical book that deals with the method of disembodiment of the soul. Its main objective is to help humans develop themselves to the extent of realising the Supreme Power/God.

The Yoga is a science of psycho-engineering. It provides all the tools and techniques to engineer the human mind so that an individual being may be elevated to divinity. It reveals the secrets of life, death and mokṣa. Just as physical sciences and technologies involve kinetic and potential energies for their operation; similarly, the science of psycho-engineering and māntrika technology developed in ancient India was based on Bhāvanā Sanskāra or psychic energy of Vaśeṣika tradition. The Yogadarśana teaches us how to pool the psychic energy and utilise it in achieving various siddhis or divine powers. Yoga enables one to command over one’s mental functions or processes and develop one's full potential.

The Sāṅkhya of Kapila 

Generally, scholars think that the Sāṅkhya Darśana deals with the creation of the universe. Nevertheless, the creation of the universe is not the primary subject of Sāṅkhya. The Sāṅkhya Darśana primarily deals with the embodiment of an individual soul. It explains the existence of Prakṛti and Puruṣa [soul] and their various characteristics. It also beautifully describes the body's production from Prakṛti. In addition, it explains the purpose of creation.

It also discusses in depth the purpose of the origin of the body, the thirteen senses and tanmātras. Two types of bodies and the soul's journey in different species have been explained remarkably. Having explained self-realisation technically [from the point of Śāstra], the means of self-realisation are described within the ambit of Śāstra through famous examples prevalent in society.

It also discusses certain other issues related to or unrelated to self-realisation that can be contrary to the fundamental principles of Sāṅkhya.

According to the Sāṅkhya, Viveka [discrimination between Soul and body] leads to apavarga [self-realisation].

However, we can indirectly infer the process of physical creation as per Sāṅkhya.

As per Sāṅkhya, ahaṅkāra from the point of sattva, rajas and tamas guṇas is of three types—Taijas Ahaṅkāra, Vaikārika Ahaṅkāra and Bhūtādi Ahaṅkāra.

(1). From Taijas ahaṅkāra proceed mind, five sensory organs. 

(2). From Vaikārika ahaṅkāra proceed motor organs.

(3). From Bhūtādi ahaṅkāra proceed five bhūta [matter] tanmātras [sensations], and from five Bhūta [matter] tanmātras proceed active matter particles [electrons, protons and neutrons] forming five gross elements [representing five states of matter].

According to Sāṅkhya prakṛi has two forms—sat and asat. However, prakṛti is the same irrespective of its two forms.

समानः प्रकृतेर्द्वयेाः ॥ ३४ ॥

samānaḥ prakṛterdvayoḥ ॥ 34॥

[Meaning 1] (dvayoḥ) Between two —soul and Prakṛti, (samānaḥ) it is proper to accept (prakṛteḥ) Prakṛti as the material cause of the bodies of souls or creation.

[Meaning 2] Prakṛti has two forms—sat and asat. In the form of sat, it is eternal, but in the form of asat, it continues to change. In its causal form, Prakṛti is sat, and in its product form, Prakṛti is asta. The sūtra says that (prakṛteḥ) Prakṛti is (samānam) the same irrespective of its (dvayoḥ) two forms.

In its sat form, the three guṇas are in a balanced state or remain inactive, but in its asat form, the three guṇas are imbalanced and become active. These three guṇas of Sāṅkhya have three different properties— sattva has the property of rāga [attraction], rajas have the property of virāga [repulson], and tamas has the property of neutrality. These three guṇas — sattva, rajas and tamas are operative in three material particles called electrons, protons, and neutrons. 

Due to the above-cited fundamental properties of sattva, rajas and tamas guṇas, particles also have the tendency of attraction-repulsion [electrons and protons] and neutrality [neutrons].  

Sāṅkhya also says that prakṛti [energy], being insentient [jaḍa], cannot be active until and unless it is activated by some external chetana [sentient] force called Brahman.