Gradgrind's attitude towards human experience, and towards life, can be seen in three details: his name, his insistence on facts, and his repeated discussions of himself.
The name indicates that life is hard: humanity can expect to be ground down.
His insistence on facts indicates that he thinks the world is a known place (rather than an adventure or source of mystery), that he knows it, and that externally verifiable data are superior to the soul, the spirit, imagination, etc. Again, this would make the human experience cold and fairly hard.
His repeated discussions of himself show that he expects human experience to be, well, self-centered. People will defer to power; it is better to have power than not.