Now lets come to the Nyaya discipline which actually gives a good classification of types of matter (Dravya / substances) and also the different qualities of the dravya.
But before we jump into that lets see some background. Gautama Maharsi who composed the Nyaya-sutra is called "Aksapada". He was always so wrapped up in thought that he was often oblivious of the outside world. We call scientists, professors and such people "absent-minded" and retail jokes about them. Gautama too was absent-minded. One day as he was walking along, brooding over some philosophical problem, he fell into a well. Lord Shiva then rescued him and fixed eyes to his feet. Thus, as he walked, he would be guided by the pair of new eyes. That is how he came to be called "Aksapada", one with eyes on his feet. Aksha means eyes and pada means legs in sanskrit. So goes the story.
The point as per my understanding is Hinduism is not all about rituals and gods and mythology. This section of philosophy called Nyaya, which actually deals with Logic or the art of right thinking claims to take your to the ultimate through Tarka and logic.
Now lets try to answer couple of questions:
1. What are basic building elements upon which this universe is built? If you are material physicist or chemist then you may take the names of 85+ elements. If you are nuclear physicist then you have a list of unknown, unseen particles like neutrino, positron, electrons, neutrons, quarks etc. If you are an eastern philosopher then you may list the 5 elements Pancha bhutas like Earth, Water, Fire, Air and Space. In Chinese its Wood and Metal instead of Air and Space.
Per Nyaya doctrine, substance or Dravya or Matter is divided into 9 categories. They are:
Each and every thing living or non-living thing we encounter in this universe (not just the earth) has to be composed of one or more of the nine items above.
Now lets look at the Quality of the matter. What is the quality of a substance?
Element Earth has smell has its quality. Element water has taste as its primary quality. Wind has touch as its primary quality. Likewise there are 24 primary qualities listed. Each matter may have one or more of the 24 qualities listed. These 24 qualities are:
While there are many websites & books which deals with each Substance and also the quality of the Dravya, i am not planning to get into those discussions.
If you have noticed Cognition or Buddhi is one of the qualities listed above and lets look at what this is all about in the next part.