What does this sentence mean "painting of individuals with inner lives that we recognise as our own"

Solution 1:

You may grasp the meaning of individuals with inner lives from this Wiki excerpt:

Giotto's depiction of the human face and emotion sets his work apart from that of his contemporaries. When the disgraced Joachim returns sadly to the hillside, the two young shepherds look sideways at each other. The soldier who drags a baby from its screaming mother in the Massacre of the Innocents does so with his head hunched into his shoulders and a look of shame on his face. The people on the road to Egypt gossip about Mary and Joseph as they go. Of Giotto's realism, the 19th-century English critic John Ruskin said, "He painted the Madonna and St. Joseph and the Christ, yes, by all means... but essentially Mamma, Papa and Baby". Wiki

The people Giotto paints aren't "place holders" or approximations of, say, a generic Madonna and Joseph, where one male or female face might be switched with any other, but rather individual humans whose depictions capture emotions, a life of experience, and inner thoughts—humans as we see them in later realistic schools of painting and recognize in ourselves and others. Facial expressions tell the story as much as the work's other elements and composition.

You can rule out abstractionism by looking at illustrations of Giotto's works or by looking at the dates he was active and the dates of the first abstact paintings.