A twelve-tone lullaby by Arnold Schoenberg, if there were such an anomaly, would be more likely to induce nightmares than sweet dreams. Similarly, only a tin ear would ever confuse Messiaen with Mozart or Stockhausen with Schubert. Notes blending in harmony are, or should be, easy to distiguish from dissonance or atonality. It might be worth considering how often the inharmonies we experience are a result of the clash in our minds of disparate thoughts, speech, or actions which do not blend in concord.
No matter how many pure thoughts we may entertain, a single devilish or even "innocent" impish one can result in a discordant emulsion of sickness, disease, or discord. We should not forget or ignore the treachery of mortal mind, false belief, which would ever attempt to confine (Mrs. Eddy's word) or hedge us about with its unreality as a means of marring and molesting (Mrs. Eddy's words) the pure idea which is God's man, His reflection. The slightest impurity renders the whole impure. It is written that "whosoever shall keep the whole law, and yet offend in one point, he is guilty of all." (James 2: 10)
Dura lex sed lex. Hard words. Yet we can be grateful that Christ Jesus has shown us the Way, that Mary Baker Eddy has given us the means in Christian Science, and that our dear Father-Mother God has endowed each of us with the necessary ability to work out his own salvation. "The work to be performed is ours,/The strength is all His own." (Hymn 354)