The aim of this paper is to interpret and criticize the theory of theistic natural signs, formulated by Charles S. Evans. TNS are characteristic experiences or features of the world which cause the person who encounters them to form certain basic beliefs about the existence and nature of God. I propose two interpretations of how TNS work, using the categories of perception and indirect perceptual recognition. I also present two arguments against the theory of TNS. First, I point out that (...) the theory does not explain adequately why TNS are ambiguous, i.e., can be read in different ways. Second, I observe that certain experiences may be taken to be „atheistic natural signs”. Their existence gives one a reason to suspect that God is a deceiver. (shrink)