How can an infallible Church approve such sciences today after bitterly opposing them in the past?

Prudential decrees against a few particular theories in the field of science cannot rightly be construed as opposition to science. Also, such decrees are outside the field to which infallibility is restricted, and consequently do not affect that aspect of the Church. 510. The Church is infallible in her moral teachings, and her opposition was on moral grounds. The Church is infallible in her official definitions of correct moral teaching. But disciplinary decrees of Roman Congregations are not definitions of doctrine, and are not infallible. It is one thing to define a doctrine concerning moral principles, but quite another to regulate conduct in accordance with such principles as one believes them to apply to particular circumstances in some given period. 511. I am surprised that you should even try to defend the obviously superstitious teachings of Catholicism, and gloss them over. I am afraid that you begin with the belief that Catholic teaching is "obviously superstitious"; and ...  more