Jitter lines in ggplot - code works without "position =" argument

tidyverse
1

I have tried many ways to jitter my lines (vertically) in ggplot and have had no success. Different error messages for different attempts, but here's one of them:

CODE:

ggplot(cont_surv, 
       aes(
          x=Day,
          y=percent_surv,
          group = treatment,
          xlab = "Days since drought treatment start",
          ylab = "Percent surviving"
        )
 )+
   geom_line(aes(linetype=treatment,
                 color = treatment,
                 position=position_dodge(width=0.2), #removing this line => code works
   )) +
   
   scale_linetype_manual(values= c(5,5,1,1,4,4,3,3)
 )+
   scale_color_manual(values=c(
     "chartreuse3", 
     "brown", 
     "chartreuse3",
     "brown",
     "chartreuse3",
     "brown",
     "chartreuse3",
     "brown"
   ))+
   scale_size_manual(values=c(1,1.5))

### ERROR MESSAGE:

#Warning: Ignoring unknown aesthetics: position
#Don't know how to automatically pick scale for object of type PositionDodge/Position/ggproto/gg. #Defaulting to continuous.
#Error: Aesthetics must be valid data columns. Problematic aesthetic(s): position = position_dodge(width #= 0.2). 
#Did you mistype the name of a data column or forget to add stat()?