Hello:
It took me some time to verify the following information for myself.
On 8 December 1939, the Sacred Congregation for the Propagation of the Faith promulgated the Instruction
Plane compertum est (A. A. S., vol. xxxii. pp. 24-26), signed by the Prefect of the same Roman Congregation His Eminence Pietro Cardinal Fumasoni Biondi, after having obtained the express approval of Pope Pius XII in an audience granted on 7 December, regarding certain ceremonies and oaths in Chinese rites,
circa quasdam caeremonias et juramentum super ritibus sinensibus.
As Rev. Fr. Henry Davis explains in his work,
Moral and Pastoral Theology (vol. I., treatise V., ch. viii., p. 352; London and New York: Sheed and Ward, 1958):
Chinese Rites
The ceremonies in honour of Confucius are not religious. Catholics are not forbidden to be present at them. Pictures of Confucius may be placed in Catholic schools and saluted with a bow of the head. The presence of Catholic officials and students at public ceremonies which have the appearance of being superstitious is tolerated, provided their presence is passive and their marks of respect can be regarded as merely secular, otherwise they should make their intention known in order to preclude a wrong interpretation. Bowing the head and showing other marks of civil respect before images or a plaque of the dead is permissible.
The same Instruction declared superfluous the oath mandated by the Apostolic Constitution of Pope Benedict XIV
Ex quo singulari (11 July 1742) whereby Missionaries in the Chinese Empire and its adjacent kingdoms and provinces pledged themselves to forbid the faithful to partake in these rites.
As the Instruction says, the Chinese government had expressly declared that such ceremonies are not inherently religious, nor was there a religious intention when it formulated and promulgated the edicts that prescribed these civic ceremonies. The ceremonies were meant as expressions of civic solidarity and honor of cultural heritage, commemorating the most celebrated ethicist of Chinese history (
caeremonias, quae in honorem Confucii a publicis Auctoritatibus sive peraguntur sive iubentur, non fieri animo tribuendi religiosum cultum, sed hunc solum in finem ut foveatur et expromatur in virum clarissimum dignus honor et in traditiones patrum debitus cultus).
If there is danger of scandal when officials and students are obliged to partake in ostensibly superstitious ceremonies, the correct intention according to the profession and practice of the holy faith is to be expressly stated by the individuals in question (
Si quando timeatur scandalum, declaretur recta catholicorum intentio).
It should be considered that Confucius was an ethicist who lived some four centuries or so before the preaching of the Sacred Gospel unto the heathen nations. As far as I know, his ethical teachings in themselves were not contrary to natural law.
I do not know how apt the analogy is, but there is a difference between admiring Plato and admiring Plotinus. The former lived before the preaching of the Gospel unto Greece and influenced the early Fathers in profound ways. The latter was a Neo-Platonic philosopher who lived after the preaching of the Gospel and was taught by an apostatized Christian. Although some passages of his
Enneads are exceedingly beautiful, he cannot command the indulgence as Plato does for his purer works because Plotinus rejected the Gospel outright.