The reason for the low cutoff is to correct for multiple hypothesis testing. Any what do you mean by "opposite of how p-values work"? Obviously if P(data or m

The reason for the low cutoff is to correct for multiple hypothesis testing. Any what do you mean by "opposite of how p-values work"? Obviously if P(data or more extreme|null hypothesis) = 10^-8 it's significantly less likely to see the data if the null hypothesis was true, than if P(data or more extreme| null hypothesis) = 10^-7.