An answer to this Kant's question posed 240 years ago has not yet been found.
Now the answer to the question can be obtained in the framework of the New Cognitive Paradigm. See for details
Melkikh A.V., Khrennikov A., Yampolskiy. Quantum metalanguage and the new cognitive synthesis. Neuroquantology. 2019. V. 17, issue 1, 50-72.
Article Quantum Metalanguage and The New Cognitive Synthesis