On what grounds was Titchener’s approach to introspection criticized? How did he answer his critics?
Titchener defined introspection as a generic word, and said that it included an indefinitely huge group of particular methodical procedures. Titchener did not want the use of everyday words to dampen the spirit of his cleverly designed experiments.
His observers when describing anything, used their previous knowledge, this is totally against to what Titchener wanted. For example, I see a bus. Here the bus is the stimuli about which his subjects already have the information. By just saying the bus, they are not divulging their inner conscious experience about the stimuli.
Introspection met with a lot of criticism. Titcheners views on introspection were also attacked. So, to solve this problem of vocabulary, Titchener defined a language within the observers. Titchener and Wundt, both believed that external interference in the conscious experience of the observer caused error.
As all these experiments were happening in well trained positions. Hence, all these observers could be trained to understand the same language or vocabulary. The introspective language helped multiple observers. At many times it happened that observers gave different results for the same question. This gap, Titchener tried to bridge.