In science we do not actually prove theories but rather provisionally accept them if fail to reject them given data.
You can try to empirically test whether there is inflation and money supply by various time series techniques. For example, De Grauwe & Polan (2005) or Frain (2004) use Granger causality to show that lags of growth rates money supply can explain inflation rates. This would be evidence consistent with assertion that money supply growth leads to inflation.
This is not the only model that can be used. The correct model will depend on data availability & quality, and what exactly you want to test. For example, if you want to test the following hypothesis:
For example, if we have double increase in the money supply then we'll have double change in exchange rate (devaluation of the currency).
Granger causality test would not be sufficient because your statement requires that there is not just causal relationship where increase in money supply leads to drop in exchange rate. You must go extra mile to check whether the relationship is exactly proportional. This will mean on top of your prefered model you have to extract estimated coefficients and test whether the coefficient size is statistically significantly different form unity (which would be evidence against the assertion) or not. There are various tests for this, without any more details its difficult to recommend any particular test.